exclude examples from package

add license
add pre-commit
2026-05-17 23:14:53 -07:00 · 2026-05-17 23:11:32 -07:00 · 2026-05-17 22:58:14 -07:00 · 2026-05-17 22:58:00 -07:00 · 2026-05-17 22:53:33 -07:00 · 2026-05-16 16:24:57 -07:00
25 changed files with 2373 additions and 689 deletions
@@ -1 +1,3 @@
 /target
+.zed
+.gdbinit
@@ -0,0 +1,39 @@
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.5.0
+    hooks:
+      - id: fix-byte-order-marker
+      - id: check-case-conflict
+      - id: check-merge-conflict
+      - id: check-symlinks
+      - id: check-yaml
+      - id: end-of-file-fixer
+      - id: mixed-line-ending
+      - id: trailing-whitespace
+  - repo: https://github.com/pre-commit/pre-commit
+    rev: v3.6.2
+    hooks:
+      - id: validate_manifest
+  - repo: https://github.com/jorisroovers/gitlint
+    rev: v0.19.1
+    hooks:
+      - id: gitlint
+  - repo: https://github.com/FeryET/pre-commit-rust
+    rev: v1.2.1
+    hooks:
+      - id: fmt
+      - id: cargo-check
+      - id: clippy
+      - id: build
+  - repo: local
+    hooks:
+      - id: readme
+        name: readme
+        language: system
+        description: Rebuild README.md
+        types: [file]
+        files: src/lib.rs
+        stages:
+          - pre-commit
+        entry: cargo readme > README.md
+        pass_filenames: false
@@ -2,18 +2,71 @@
 # It is not intended for manual editing.
 version = 4

+[[package]]
+name = "aho-corasick"
+version = "1.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddd31a130427c27518df266943a5308ed92d4b226cc639f5a8f1002816174301"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "atomic-polyfill"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8cf2bce30dfe09ef0bfaef228b9d414faaf7e563035494d7fe092dba54b300f4"
+dependencies = [
+ "critical-section",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c08606f8c3cbf4ce6ec8e28fb0014a2c086708fe954eaa885384a6165172e7e8"

+[[package]]
+name = "bare-metal"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5deb64efa5bd81e31fcd1938615a6d98c82eafcbcd787162b6f63b91d6bac5b3"
+dependencies = [
+ "rustc_version 0.2.3",
+]
+
+[[package]]
+name = "bbqueue"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68917624e17aad88607cb5a5936f6da9b607c48c711e4e9ed101e7189aed28c2"
+dependencies = [
+ "const-init",
+ "critical-section",
+ "maitake-sync",
+]
+
+[[package]]
+name = "bitfield"
+version = "0.13.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "46afbd2983a5d5a7bd740ccb198caf5b82f45c40c09c0eed36052d91cb92e719"
+
 [[package]]
 name = "bitflags"
 version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"

+[[package]]
+name = "block-buffer"
+version = "0.10.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3078c7629b62d3f0439517fa394996acacc5cbc91c5a20d8c658e77abd503a71"
+dependencies = [
+ "generic-array 0.14.7",
+]
+
 [[package]]
 name = "byteorder"
 version = "1.5.0"
@@ -30,20 +83,111 @@ dependencies = [
 "embedded-io",
 ]

+[[package]]
+name = "cc"
+version = "1.2.62"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1dce859f0832a7d088c4f1119888ab94ef4b5d6795d1ce05afb7fe159d79f98"
+dependencies = [
+ "find-msvc-tools",
+ "shlex",
+]
+
+[[package]]
+name = "cfg-if"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
+
+[[package]]
+name = "cipher"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "773f3b9af64447d2ce9850330c473515014aa235e6a783b02db81ff39e4a3dad"
+dependencies = [
+ "crypto-common",
+ "inout",
+]
+
+[[package]]
+name = "const-init"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4bd422bfb4f24a97243f60b6a4443e63d810c925d8da4bb2d8fde26a7c1d57ec"
+
+[[package]]
+name = "cordyceps"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "688d7fbb8092b8de775ef2536f36c8c31f2bc4006ece2e8d8ad2d17d00ce0a2a"
+dependencies = [
+ "loom",
+ "tracing",
+]
+
+[[package]]
+name = "cortex-m"
+version = "0.7.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8ec610d8f49840a5b376c69663b6369e71f4b34484b9b2eb29fb918d92516cb9"
+dependencies = [
+ "bare-metal",
+ "bitfield",
+ "critical-section",
+ "embedded-hal 0.2.7",
+ "volatile-register",
+]
+
+[[package]]
+name = "cortex-m-rt"
+version = "0.7.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "801d4dec46b34c299ccf6b036717ae0fce602faa4f4fe816d9013b9a7c9f5ba6"
+dependencies = [
+ "cortex-m-rt-macros",
+]
+
+[[package]]
+name = "cortex-m-rt-macros"
+version = "0.7.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e37549a379a9e0e6e576fd208ee60394ccb8be963889eebba3ffe0980364f472"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "critical-section"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "790eea4361631c5e7d22598ecd5723ff611904e3344ce8720784c93e3d83d40b"
+
+[[package]]
+name = "crypto-common"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "78c8292055d1c1df0cce5d180393dc8cce0abec0a7102adb6c7b1eef6016d60a"
+dependencies = [
+ "generic-array 0.14.7",
+ "typenum",
+]
+
 [[package]]
 name = "defmt"
 version = "0.3.100"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f0963443817029b2024136fc4dd07a5107eb8f977eaf18fcd1fdeb11306b64ad"
 dependencies = [
- "defmt 1.0.1",
+ "defmt 1.1.0",
 ]

 [[package]]
 name = "defmt"
-version = "1.0.1"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "548d977b6da32fa1d1fda2876453da1e7df63ad0304c8b3dae4dbe7b96f39b78"
+checksum = "a6e524506490a1953d237cb87b1cfc1e46f88c18f10a22dfe0f507dc6bfc7f7f"
 dependencies = [
 "bitflags",
 "defmt-macros",
@@ -51,9 +195,9 @@ dependencies = [

 [[package]]
 name = "defmt-macros"
-version = "1.0.1"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3d4fc12a85bcf441cfe44344c4b72d58493178ce635338a3f3b78943aceb258e"
+checksum = "f0a27770e9c8f719a79d8b638281f4d828f77d8fd61e0bd94451b9b85e576a0b"
 dependencies = [
 "defmt-parser",
 "proc-macro-error2",
@@ -71,12 +215,107 @@ dependencies = [
 "thiserror",
 ]

+[[package]]
+name = "defmt-rtt"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c0f73a4a4a91609e977ae3b7bd831ffa292edfd42ad140a3244a61d805b0e05e"
+dependencies = [
+ "critical-section",
+ "defmt 1.1.0",
+]
+
+[[package]]
+name = "digest"
+version = "0.10.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9ed9a281f7bc9b7576e61468ba615a66a5c8cfdff42420a70aa82701a3b1e292"
+dependencies = [
+ "block-buffer",
+ "crypto-common",
+]
+
+[[package]]
+name = "embedded-hal"
+version = "0.2.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "35949884794ad573cf46071e41c9b60efb0cb311e3ca01f7af807af1debc66ff"
+dependencies = [
+ "nb 0.1.3",
+ "void",
+]
+
+[[package]]
+name = "embedded-hal"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "361a90feb7004eca4019fb28352a9465666b24f840f5c3cddf0ff13920590b89"
+
 [[package]]
 name = "embedded-io"
 version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9eb1aa714776b75c7e67e1da744b81a129b3ff919c8712b5e1b32252c1f07cc7"

+[[package]]
+name = "embedded-time"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d7a4b4d10ac48d08bfe3db7688c402baadb244721f30a77ce360bd24c3dffe58"
+dependencies = [
+ "num",
+]
+
+[[package]]
+name = "find-msvc-tools"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5baebc0774151f905a1a2cc41989300b1e6fbb29aff0ceffa1064fdd3088d582"
+
+[[package]]
+name = "generator"
+version = "0.8.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "52f04ae4152da20c76fe800fa48659201d5cf627c5149ca0b707b69d7eef6cf9"
+dependencies = [
+ "cc",
+ "cfg-if",
+ "libc",
+ "log",
+ "rustversion",
+ "windows-link",
+ "windows-result",
+]
+
+[[package]]
+name = "generic-array"
+version = "0.14.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85649ca51fd72272d7821adaf274ad91c288277713d9c18820d8499a7ff69e9a"
+dependencies = [
+ "typenum",
+ "version_check",
+]
+
+[[package]]
+name = "generic-array"
+version = "1.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dab9e9188e97a93276e1fe7b56401b851e2b45a46d045ca658100c1303ada649"
+dependencies = [
+ "rustversion",
+ "typenum",
+]
+
+[[package]]
+name = "hash32"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b0c35f58762feb77d74ebe43bdbc3210f09be9fe6742234d573bacc26ed92b67"
+dependencies = [
+ "byteorder",
+]
+
 [[package]]
 name = "hash32"
 version = "0.3.1"
@@ -86,16 +325,188 @@ dependencies = [
 "byteorder",
 ]

+[[package]]
+name = "heapless"
+version = "0.7.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cdc6457c0eb62c71aac4bc17216026d8410337c4126773b9c5daba343f17964f"
+dependencies = [
+ "atomic-polyfill",
+ "hash32 0.2.1",
+ "rustc_version 0.4.1",
+ "spin",
+ "stable_deref_trait",
+]
+
 [[package]]
 name = "heapless"
 version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0bfb9eb618601c89945a70e254898da93b13be0388091d42117462b265bb3fad"
 dependencies = [
- "hash32",
+ "hash32 0.3.1",
 "stable_deref_trait",
 ]

+[[package]]
+name = "inout"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "879f10e63c20629ecabbb64a8010319738c66a5cd0c29b02d63d272b03751d01"
+dependencies = [
+ "generic-array 0.14.7",
+]
+
+[[package]]
+name = "lazy_static"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
+
+[[package]]
+name = "libc"
+version = "0.2.186"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68ab91017fe16c622486840e4c83c9a37afeff978bd239b5293d61ece587de66"
+
+[[package]]
+name = "lock_api"
+version = "0.4.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "224399e74b87b5f3557511d98dff8b14089b3dadafcab6bb93eab67d3aace965"
+dependencies = [
+ "scopeguard",
+]
+
+[[package]]
+name = "log"
+version = "0.4.29"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e5032e24019045c762d3c0f28f5b6b8bbf38563a65908389bf7978758920897"
+
+[[package]]
+name = "log-to-defmt"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9454118d78a9089a15d702fbaf413da2fa23f331b8af6c5eed5784a4369173c6"
+dependencies = [
+ "defmt 0.3.100",
+ "heapless 0.7.17",
+ "log",
+]
+
+[[package]]
+name = "loom"
+version = "0.7.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "419e0dc8046cb947daa77eb95ae174acfbddb7673b4151f56d1eed8e93fbfaca"
+dependencies = [
+ "cfg-if",
+ "generator",
+ "scoped-tls",
+ "tracing",
+ "tracing-subscriber",
+]
+
+[[package]]
+name = "lpc55-hal"
+version = "0.5.0"
+source = "git+https://github.com/ktims/lpc55-hal?branch=main#8dfefd62aff4abd2de535f23107812dda68437be"
+dependencies = [
+ "block-buffer",
+ "cipher",
+ "cortex-m",
+ "digest",
+ "embedded-hal 0.2.7",
+ "embedded-time",
+ "generic-array 1.4.1",
+ "lpc55-pac",
+ "nb 1.1.0",
+ "rand_core",
+ "usb-device",
+ "vcell",
+ "void",
+]
+
+[[package]]
+name = "lpc55-pac"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3a4952baed9d9e7e82a6bbc87333f939b90eb41df3e6c0be5e35d0ec61005f91"
+dependencies = [
+ "cortex-m",
+ "cortex-m-rt",
+ "vcell",
+]
+
+[[package]]
+name = "lpc55s28-evk"
+version = "0.1.0"
+dependencies = [
+ "bbqueue",
+ "cortex-m",
+ "cortex-m-rt",
+ "defmt 1.1.0",
+ "defmt-rtt",
+ "embedded-hal 1.0.0",
+ "embedded-io",
+ "log-to-defmt",
+ "lpc55-hal",
+ "panic-probe",
+ "usb-device",
+ "usbd-uac2",
+]
+
+[[package]]
+name = "lpc55s28-evk-dma"
+version = "0.1.0"
+dependencies = [
+ "cortex-m",
+ "cortex-m-rt",
+ "defmt 1.1.0",
+ "defmt-rtt",
+ "embedded-hal 1.0.0",
+ "embedded-io",
+ "log-to-defmt",
+ "lpc55-hal",
+ "nb 1.1.0",
+ "panic-probe",
+ "static_cell",
+ "usb-device",
+ "usbd-uac2",
+]
+
+[[package]]
+name = "maitake-sync"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3d77c365d697828821727b9bc09e6bc3c518b8c63804e79e1be5a5ae091a7c5f"
+dependencies = [
+ "cordyceps",
+ "critical-section",
+ "loom",
+ "mutex-traits",
+ "mycelium-bitfield",
+ "pin-project",
+ "portable-atomic",
+ "tracing",
+]
+
+[[package]]
+name = "matchers"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d1525a2a28c7f4fa0fc98bb91ae755d1e2d1505079e05539e35bc876b5d65ae9"
+dependencies = [
+ "regex-automata",
+]
+
+[[package]]
+name = "memchr"
+version = "2.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f8ca58f447f06ed17d5fc4043ce1b10dd205e060fb3ce5b979b8ed8e59ff3f79"
+
 [[package]]
 name = "modular-bitfield"
 version = "0.13.1"
@@ -117,6 +528,95 @@ dependencies = [
 "syn",
 ]

+[[package]]
+name = "mutex-traits"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3929f2b5633d29cf7b6624992e5f3c1e9334f1193423e12d17be4faf678cde3f"
+
+[[package]]
+name = "mycelium-bitfield"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "24e0cc5e2c585acbd15c5ce911dff71e1f4d5313f43345873311c4f5efd741cc"
+
+[[package]]
+name = "nb"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "801d31da0513b6ec5214e9bf433a77966320625a37860f910be265be6e18d06f"
+dependencies = [
+ "nb 1.1.0",
+]
+
+[[package]]
+name = "nb"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8d5439c4ad607c3c23abf66de8c8bf57ba8adcd1f129e699851a6e43935d339d"
+
+[[package]]
+name = "nu-ansi-term"
+version = "0.50.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7957b9740744892f114936ab4a57b3f487491bbeafaf8083688b16841a4240e5"
+dependencies = [
+ "windows-sys",
+]
+
+[[package]]
+name = "num"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b7a8e9be5e039e2ff869df49155f1c06bd01ade2117ec783e56ab0932b67a8f"
+dependencies = [
+ "num-complex",
+ "num-integer",
+ "num-iter",
+ "num-rational",
+ "num-traits",
+]
+
+[[package]]
+name = "num-complex"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "747d632c0c558b87dbabbe6a82f3b4ae03720d0646ac5b7b4dae89394be5f2c5"
+dependencies = [
+ "num-traits",
+]
+
+[[package]]
+name = "num-integer"
+version = "0.1.46"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7969661fd2958a5cb096e56c8e1ad0444ac2bbcd0061bd28660485a44879858f"
+dependencies = [
+ "num-traits",
+]
+
+[[package]]
+name = "num-iter"
+version = "0.1.45"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1429034a0490724d0075ebb2bc9e875d6503c3cf69e235a8941aa757d83ef5bf"
+dependencies = [
+ "autocfg",
+ "num-integer",
+ "num-traits",
+]
+
+[[package]]
+name = "num-rational"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "12ac428b1cb17fce6f731001d307d351ec70a6d202fc2e60f7d4c5e42d8f4f07"
+dependencies = [
+ "autocfg",
+ "num-integer",
+ "num-traits",
+]
+
 [[package]]
 name = "num-traits"
 version = "0.2.19"
@@ -126,6 +626,48 @@ dependencies = [
 "autocfg",
 ]

+[[package]]
+name = "once_cell"
+version = "1.21.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9f7c3e4beb33f85d45ae3e3a1792185706c8e16d043238c593331cc7cd313b50"
+
+[[package]]
+name = "panic-probe"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fd402d00b0fb94c5aee000029204a46884b1262e0c443f166d86d2c0747e1a1a"
+dependencies = [
+ "cortex-m",
+ "defmt 1.1.0",
+]
+
+[[package]]
+name = "pin-project"
+version = "1.1.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2466b2336ed02bcdca6b294417127b90ec92038d1d5c4fbeac971a922e0e0924"
+dependencies = [
+ "pin-project-internal",
+]
+
+[[package]]
+name = "pin-project-internal"
+version = "1.1.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c96395f0a926bc13b1c17622aaddda1ecb55d49c8f1bf9777e4d877800a43f8b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "pin-project-lite"
+version = "0.2.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a89322df9ebe1c1578d689c92318e070967d1042b512afbe49518723f4e6d5cd"
+
 [[package]]
 name = "portable-atomic"
 version = "1.13.1"
@@ -172,6 +714,116 @@ dependencies = [
 "proc-macro2",
 ]

+[[package]]
+name = "rand_core"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
+
+[[package]]
+name = "regex-automata"
+version = "0.4.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6e1dd4122fc1595e8162618945476892eefca7b88c52820e74af6262213cae8f"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc897dd8d9e8bd1ed8cdad82b5966c3e0ecae09fb1907d58efaa013543185d0a"
+
+[[package]]
+name = "rustc_version"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
+dependencies = [
+ "semver 0.9.0",
+]
+
+[[package]]
+name = "rustc_version"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cfcb3a22ef46e85b45de6ee7e79d063319ebb6594faafcf1c225ea92ab6e9b92"
+dependencies = [
+ "semver 1.0.28",
+]
+
+[[package]]
+name = "rustversion"
+version = "1.0.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b39cdef0fa800fc44525c84ccb54a029961a8215f9619753635a9c0d2538d46d"
+
+[[package]]
+name = "scoped-tls"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e1cf6437eb19a8f4a6cc0f7dca544973b0b78843adbfeb3683d1a94a0024a294"
+
+[[package]]
+name = "scopeguard"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
+
+[[package]]
+name = "semver"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
+dependencies = [
+ "semver-parser",
+]
+
+[[package]]
+name = "semver"
+version = "1.0.28"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8a7852d02fc848982e0c167ef163aaff9cd91dc640ba85e263cb1ce46fae51cd"
+
+[[package]]
+name = "semver-parser"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
+
+[[package]]
+name = "sharded-slab"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f40ca3c46823713e0d4209592e8d6e826aa57e928f09752619fc696c499637f6"
+dependencies = [
+ "lazy_static",
+]
+
+[[package]]
+name = "shlex"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
+
+[[package]]
+name = "smallvec"
+version = "1.15.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "67b1b7a3b5fe4f1376887184045fcf45c69e92af734b7aaddc05fb777b6fbd03"
+
+[[package]]
+name = "spin"
+version = "0.9.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
+dependencies = [
+ "lock_api",
+]
+
 [[package]]
 name = "stable_deref_trait"
 version = "1.2.1"
@@ -184,6 +836,15 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"

+[[package]]
+name = "static_cell"
+version = "2.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0530892bb4fa575ee0da4b86f86c667132a94b74bb72160f58ee5a4afec74c23"
+dependencies = [
+ "portable-atomic",
+]
+
 [[package]]
 name = "syn"
 version = "2.0.117"
@@ -215,6 +876,82 @@ dependencies = [
 "syn",
 ]

+[[package]]
+name = "thread_local"
+version = "1.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f60246a4944f24f6e018aa17cdeffb7818b76356965d03b07d6a9886e8962185"
+dependencies = [
+ "cfg-if",
+]
+
+[[package]]
+name = "tracing"
+version = "0.1.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "63e71662fa4b2a2c3a26f570f037eb95bb1f85397f3cd8076caed2f026a6d100"
+dependencies = [
+ "pin-project-lite",
+ "tracing-attributes",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-attributes"
+version = "0.1.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7490cfa5ec963746568740651ac6781f701c9c5ea257c58e057f3ba8cf69e8da"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "tracing-core"
+version = "0.1.36"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "db97caf9d906fbde555dd62fa95ddba9eecfd14cb388e4f491a66d74cd5fb79a"
+dependencies = [
+ "once_cell",
+ "valuable",
+]
+
+[[package]]
+name = "tracing-log"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee855f1f400bd0e5c02d150ae5de3840039a3f54b025156404e34c23c03f47c3"
+dependencies = [
+ "log",
+ "once_cell",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-subscriber"
+version = "0.3.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cb7f578e5945fb242538965c2d0b04418d38ec25c79d160cd279bf0731c8d319"
+dependencies = [
+ "matchers",
+ "nu-ansi-term",
+ "once_cell",
+ "regex-automata",
+ "sharded-slab",
+ "smallvec",
+ "thread_local",
+ "tracing",
+ "tracing-core",
+ "tracing-log",
+]
+
+[[package]]
+name = "typenum"
+version = "1.20.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "40ce102ab67701b8526c123c1bab5cbe42d7040ccfd0f64af1a385808d2f43de"
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.24"
@@ -228,7 +965,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "98816b1accafbb09085168b90f27e93d790b4bfa19d883466b5e53315b5f06a6"
 dependencies = [
 "defmt 0.3.100",
- "heapless",
+ "heapless 0.8.0",
 "portable-atomic",
 ]

@@ -237,9 +974,66 @@ name = "usbd-uac2"
 version = "0.1.0"
 dependencies = [
 "byteorder-embedded-io",
- "defmt 1.0.1",
+ "defmt 1.1.0",
 "embedded-io",
 "modular-bitfield",
 "num-traits",
 "usb-device",
 ]
+
+[[package]]
+name = "valuable"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ba73ea9cf16a25df0c8caa16c51acb937d5712a8429db78a3ee29d5dcacd3a65"
+
+[[package]]
+name = "vcell"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77439c1b53d2303b20d9459b1ade71a83c716e3f9c34f3228c00e6f185d6c002"
+
+[[package]]
+name = "version_check"
+version = "0.9.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b928f33d975fc6ad9f86c8f283853ad26bdd5b10b7f1542aa2fa15e2289105a"
+
+[[package]]
+name = "void"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
+
+[[package]]
+name = "volatile-register"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "de437e2a6208b014ab52972a27e59b33fa2920d3e00fe05026167a1c509d19cc"
+dependencies = [
+ "vcell",
+]
+
+[[package]]
+name = "windows-link"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
+
+[[package]]
+name = "windows-result"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7781fa89eaf60850ac3d2da7af8e5242a5ea78d1a11c49bf2910bb5a73853eb5"
+dependencies = [
+ "windows-link",
+]
+
+[[package]]
+name = "windows-sys"
+version = "0.61.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
+dependencies = [
+ "windows-link",
+]
@@ -1,10 +1,27 @@
+[workspace]
+members = [
+    "examples/lpc55s28-evk",
+    "examples/lpc55s28-evk-dma"
+]
+resolver = "2"
+
+[workspace.dependencies]
+usb-device = { version = "0.3", features = ["control-buffer-256"] }
+usbd-uac2 = { path = "." }
+
 [package]
 name = "usbd-uac2"
 description = "USB Audio Class 2.0 for usb-device"
+readme = "README.md"
 authors = ["Keenan Tims <ktims@gotroot.ca>"]
+repository = "https://github.com/ktims/usbd_uac2"
 version = "0.1.0"
 edition = "2024"
-keywords = ["no-std", "usb-device"]
+license = "MIT"
+keywords = ["no-std", "usb-device", "audio"]
+exclude = [
+    "examples/**"
+]

 [features]
 defmt = ["dep:defmt", "usb-device/defmt"]
@@ -15,4 +32,10 @@ defmt = { version = "1.0.1", optional = true }
 embedded-io = "0.7.1"
 modular-bitfield = "0.13.1"
 num-traits = { version = "0.2.19", default-features = false }
-usb-device = { version = "0.3", features = ["control-buffer-256"] }
+usb-device.workspace = true
+
+[profile.release]
+opt-level = "z"
+lto = true
+debug = true
+codegen-units = 1
@@ -0,0 +1,18 @@
+Copyright 2026 Keenan Tims
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the “Software”), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
@@ -0,0 +1,45 @@
+# usbd-uac2
+
+USB Audio Class 2.0
+
+This crate provides a USB Audio Class 2.0 implementation for
+[usb-device](https://crates.io/crates/usb-device). It implements all
+required elements of the specification, however many controls are not
+implemented (e.g. mixers, effects).
+
+Device behaviour is driven by implementing the `ClockSource` and
+`AudioHandler` traits to configure the audio pipeline and source/sink data
+to/from USB.
+
+Example (creates a UAC2 device with in and out streams):
+
+```rust
+let mut audio = YourTraitImpl {...};
+
+let config = UsbAudioClassConfig::new(usb_speed, FunctionCode::IoBox, &mut audio)
+    // base_id is USB entity ID, id 1 is always taken by the clock source, and each stream builds 2 entities
+    .with_output_config(TerminalConfig::builder().base_id(2).build())
+    .with_input_config(TerminalConfig::builder().base_id(4).build());
+
+let mut uac2 = config.build(&usb_bus).unwrap();
+
+let mut usb_dev = usbd_uac2::builder(&usb_bus, UsbVidPid(0x1209, 0x0001))
+    .strings(&[StringDescriptors::default()
+        .manufacturer("usbd_uac2")
+        .product("example")])
+    .unwrap()
+    .max_packet_size_0(64) // Required to be 64 on HS
+    .unwrap()
+    .build();
+```
+
+No work needs to be done in the poll loop, the class implementation will
+call your trait callbacks as required, just call the usb poll as usual:
+
+```rust
+loop {
+    usb_dev.poll(&mut [&mut uac2]);
+}
+```
+
+See the trait documentation or examples for additional details.
@@ -0,0 +1,56 @@
+Two example backends are provided, both based on the LPCXpresso55S28 demo board, using the onboard WM8904 DAC.
+
+## LPC55S28 (LPCXpresso55S28)
+
+These examples work on the
+[LPCXpresso55S28](https://www.nxp.com/design/design-center/software/development-software/mcuxpresso-software-and-tools-/lpcxpresso-boards/lpcxpresso55s28-development-board:LPC55S28-EVK)
+development board. They use the onboard WM8904 codec, so don't require any
+additional hardware for audio I/O.
+
+They can be programmed and debugged using the CMSIS-DAP that's on the board,
+though due to the security features you may need to reset into the DFU
+bootloader first.
+
+```
+cargo embed --release
+```
+
+Enable logging with `DEFMT_LOG` when building, but beware that enabling defmt
+logs can cause timing failures, and _must_ be drained by the host, as it is
+blocking.
+
+They work on either USBFS or USBHS, but not both at the same time. The default
+is USBHS. If you would like to run the example on USBFS, disable default
+features and select USBFS:
+
+```
+cargo embed --release --no-default-features --features usbfs
+```
+
+### Interrupt-driven (`lpc55s28-evk`)
+
+Running at 32bit/48khz. Simultaneous input and output. Works on USBFS and USBHS.
+
+This is a minimal implementation intended to demonstrate the fundamental
+structure of the class driver. The architecture is not recommended for a production
+device, but it does work reliably on the happy path.
+
+This is intended primarily as a reference implementation to aid understanding of
+the class driver.
+
+### DMA-based (`lpc55s28-evk-dma`)
+
+Running at 32bit/96khz. Output only. Works on USBFS and USBHS.
+
+A more realistic and robust implementation using DMA. It fills a static ring
+buffer as data comes in from USB, while the DMA chases it around the ring,
+draining into the TX FIFO. This is efficient and decouples interrupt latency
+from data delivery. It uses the DMA interrupt to track consumed slots, but as
+long as the USB doesn't catch up to the read slot before this happens, there is
+a lot of slack for other things to be happening.
+
+This is a more useful demonstration, but is still lacking correct handling of
+edge cases, error conditions and so on you would want in a fully fleshed out
+implementation. Particularly, it behaves poorly in underrun, since the DMA will
+keep emitting from the ring regardless of whether the data is valid, which
+sounds terrible.
@@ -1,10 +1,3 @@
-[target.thumbv8m.main-none-eabi]
-rustflags = [
-  "-C", "link-arg=-Tlink.x",
-  "-C", "link-arg=-Tdefmt.x",
-  "-C", "debug-assertions",
-]
-
 [target.thumbv8m.main-none-eabihf]
 rustflags = [
  "-C", "link-arg=-Tlink.x",
@@ -313,6 +313,7 @@ dependencies = [
 [[package]]
 name = "lpc55-hal"
 version = "0.5.0"
+source = "git+https://github.com/ktims/lpc55-hal?branch=main#8dfefd62aff4abd2de535f23107812dda68437be"
 dependencies = [
 "block-buffer",
 "cipher",
@@ -353,7 +354,6 @@ dependencies = [
 "log-to-defmt",
 "lpc55-hal",
 "nb 1.1.0",
- "panic-halt",
 "panic-probe",
 "static_cell",
 "usb-device",
@@ -458,12 +458,6 @@ dependencies = [
 "autocfg",
 ]

-[[package]]
-name = "panic-halt"
-version = "1.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a513e167849a384b7f9b746e517604398518590a9142f4846a32e3c2a4de7b11"
-
 [[package]]
 name = "panic-probe"
 version = "1.0.0"
@@ -2,6 +2,7 @@
 name = "lpc55s28-evk-dma"
 version = "0.1.0"
 edition = "2024"
+publish = false

 [features]
 default = ["usbhs"]
@@ -16,16 +17,10 @@ defmt-rtt = "1.1.0"
 embedded-hal = "1.0.0"
 embedded-io = "0.7.1"
 log-to-defmt = "0.1.0"
-lpc55-hal = { version = "0.5.0", path = "../lpc55-hal" }
 nb = "1.1.0"
-panic-halt = "1.0.0"
 panic-probe = { version = "1.0.0", features = ["print-defmt"] }
 static_cell = "2.1.1"
-usb-device = "0.3"
-usbd-uac2 = { version = "0.1.0", path = "../..", features = ["defmt"]}
-
-[profile.release]
-opt-level = "z"
-lto = true
-debug = true
-codegen-units = 1
+# Includes update to usb-device 0.3, fix for isochronous and smaller critical sections
+lpc55-hal = { git = "https://github.com/ktims/lpc55-hal", branch = "main" }
+usb-device.workspace = true
+usbd-uac2 = { workspace = true, features = ["defmt"] }
@@ -0,0 +1,9 @@
+[default.general]
+chip = "LPC55S28JBD100"
+[default.rtt]
+enabled = true
+[default.gdb]
+enabled = true
+
+[debug.rtt]
+enabled = false
@@ -0,0 +1,5 @@
+// Find the actual path of memory.x and add it to link search, required for building in workspace
+fn main() {
+    let manifest_dir = std::env::var("CARGO_MANIFEST_DIR").unwrap();
+    println!("cargo:rustc-link-search={}", manifest_dir);
+}
@@ -233,13 +233,37 @@ impl<const N: usize, const MAX_SLOT_BYTES: usize> DmaRing<N, MAX_SLOT_BYTES> {
    pub fn produced(&self) -> usize {
        self.produced.load(Ordering::Acquire)
    }
-
+    pub fn produced_bytes(&self) -> usize {
+        self.produced_bytes.load(Ordering::Acquire)
+    }
    pub fn consumed(&self) -> usize {
        self.consumed.load(Ordering::Acquire)
    }
    pub fn consumed_bytes(&self) -> usize {
-        self.consumed.load(Ordering::Acquire) * self.slot_bytes
-            + (self.dma.channel19.xfercfg.read().bits() as usize >> 16 & 0x3ff)
+        loop {
+            let consumed_start = self.consumed.load(Ordering::Acquire);
+
+            let reg_1 = self.dma.channel19.xfercfg.read().bits() as usize >> 16 & 0x3ff;
+            let reg_2 = self.dma.channel19.xfercfg.read().bits() as usize >> 16 & 0x3ff;
+
+            let consumed_end = self.consumed.load(Ordering::Acquire);
+
+            if consumed_start == consumed_end && reg_1 == reg_2 {
+                // 1. Map the hardware remaining countdown into a clean byte count
+                let remaining_bytes = if reg_1 == 0x3ff {
+                    0 // 0x3FF means all transfers completed, 0 bytes remaining
+                } else {
+                    // Formula from NXP manual: (XFERCOUNT + 1) * Data Width
+                    (reg_1 + 1) * self.word_bytes
+                };
+
+                // 2. Total bytes consumed in this specific active slot
+                let active_slot_consumed = self.slot_bytes - remaining_bytes;
+
+                // 3. Combine with your software index history accumulator
+                return consumed_start * self.slot_bytes + active_slot_consumed;
+            }
+        }
    }

    pub fn fill_slots(&self) -> usize {
@@ -319,7 +343,7 @@ impl<const N: usize, const MAX_SLOT_BYTES: usize> DmaRing<N, MAX_SLOT_BYTES> {
        let slots = unsafe { &mut *self.slots.get() };
        let desc = unsafe { &mut *self.desc.get() };
        let chan_desc = unsafe { &mut *self.channel_desc.get() };
-        defmt::info!("slots base: &{:x}", self.slots.get());
+        defmt::debug!("slots base: &{:x}", self.slots.get());

        // Pre-fill with silence so underrun replays silence.
        for i in 0..N {
@@ -1,22 +1,19 @@
 //! Contains hardware setup unrelated to Usb Audio Class implementation

-use crate::hal;
-use core::cell::{OnceCell, UnsafeCell};
-use core::mem::MaybeUninit;
-use core::ptr::null_mut;
-
 use crate::Syscon;
+use crate::hal;
 use crate::{MCLK_FREQ, SAMPLE_RATE, pac};
-use defmt::debug;
+
+use core::cell::UnsafeCell;
+use core::mem::MaybeUninit;
+use defmt::{debug, info};
 use hal::{
-    Iocon, Pin,
+    Enabled, Iocon, Pin,
    drivers::pins,
-    prelude::*,
    traits::wg::digital::v2::{OutputPin, ToggleableOutputPin},
    typestates::pin::{gpio::direction::Output, state::Gpio},
 };
-use lpc55_hal::Enabled;
-use static_cell::StaticCell;
+
 pub(crate) struct PllConstants {
    pub m: u16,   // 1-65535
    pub n: u8,    // 1-255
@@ -138,67 +135,12 @@ pub(crate) fn init_audio_pll() {

    pmc.pdruncfg0
        .modify(|_, w| w.pden_pll0().poweredon().pden_pll0_sscg().poweredon());
-    debug!("pll0 wait for lock");
+    info!("pll0 wait for lock");
    let mut i = 0usize;
    while syscon.pll0stat.read().lock().bit_is_clear() {
        i += 1;
    }
-    debug!("pll0 locked after {} tries", i);
-}
-
-const SYS_PLL: PllConstants = PllConstants::new(4, 75, 1); // 150MHz
-
-pub(crate) fn init_sys_pll1() {
-    let syscon = unsafe { &*pac::SYSCON::ptr() };
-    let pmc = unsafe { &*pac::PMC::ptr() };
-    let anactrl = unsafe { &*pac::ANACTRL::ptr() };
-
-    debug!("start clk_in");
-    pmc.pdruncfg0
-        .modify(|_, w| w.pden_xtal32m().poweredon().pden_ldoxo32m().poweredon());
-    syscon.clock_ctrl.modify(|_, w| w.clkin_ena().enable());
-    anactrl
-        .xo32m_ctrl
-        .modify(|_, w| w.enable_system_clk_out().enable());
-
-    debug!("init pll1: {}", SYS_PLL);
-    pmc.pdruncfg0.modify(|_, w| w.pden_pll1().poweredoff());
-    syscon.pll1clksel.write(|w| w.sel().enum_0x1()); // clk_in
-    syscon.pll1ctrl.write(|w| unsafe {
-        w.clken()
-            .enable()
-            .seli()
-            .bits(SYS_PLL.seli)
-            .selp()
-            .bits(SYS_PLL.selp)
-    });
-
-    syscon
-        .pll1ndec
-        .write(|w| unsafe { w.ndiv().bits(SYS_PLL.n) });
-    syscon.pll1ndec.write(|w| unsafe {
-        w.ndiv().bits(SYS_PLL.n).nreq().set_bit() // latch
-    });
-    syscon
-        .pll1mdec
-        .write(|w| unsafe { w.mdiv().bits(SYS_PLL.m) });
-    syscon
-        .pll1pdec
-        .write(|w| unsafe { w.pdiv().bits(SYS_PLL.p) });
-    syscon.pll1pdec.write(|w| unsafe {
-        w.pdiv().bits(SYS_PLL.p).preq().set_bit() // latch
-    });
-
-    pmc.pdruncfg0.modify(|_, w| w.pden_pll1().poweredon());
-    debug!("pll1 wait for lock");
-    let mut i = 0usize;
-    while syscon.pll1stat.read().lock().bit_is_clear() {
-        i += 1;
-    }
-    debug!("pll1 locked after {} tries", i);
-    // switch system clock to pll1
-    syscon.fmccr.modify(|_, w| w.flashtim().flashtim11());
-    syscon.mainclkselb.modify(|_, w| w.sel().enum_0x2()); // pll1
+    info!("pll0 locked after {} loops", i);
 }

 pub struct I2sTx {
@@ -207,7 +149,6 @@ pub struct I2sTx {

 pub fn init_i2s(mut fc7: pac::FLEXCOMM7, i2s7: pac::I2S7, syscon: &mut Syscon) -> I2sTx {
    defmt::debug!("init i2s");
-    // Enable BOTH
    syscon.reset(&mut fc7);
    syscon.enable_clock(&mut fc7);

@@ -1,10 +1,15 @@
-//! Interrupt driven example for the LPCXpresso55S28 demo board
+//! DMA based audio output example for the LPCXpresso55S28 demo board
 //!
-//! Uses the onboard WM8904 DAC at 48KHz. Clock is generated by PLL0. Simple PI feedback
-//! is implemented.
+//! Uses the onboard WM8904 DAC at 96KHz. Clock is generated by PLL0. Simple proportional feedback is implemented.
 //!
-//! Packets from USB are placed a `heapless::spsc::Queue`. They are consumed
-//! by the I2S FIFO in the FLEXCOMM7 interrupt.
+//! USB walks around a static ring of slots, filling them as data comes in from
+//! the host. DMA chases it, filling the I2S FIFO as it drains to the DAC.
+//! Feedback ensures that the host doesn't overrun or underrun the ring.
+//!
+//! This implementation is more suitable for real use than the interrupt-based
+//! example, but it is still missing many niceties and behaves worse in
+//! anomalous situations since the DMA just keeps trucking over the ring
+//! regardless of the data validity.
 #![no_main]
 #![no_std]

@@ -33,14 +38,12 @@ use pac::interrupt;
 use static_cell::StaticCell;
 use usb_device::{
    bus::{self},
-    device::{StringDescriptors, UsbDeviceBuilder, UsbVidPid},
-    endpoint::IsochronousSynchronizationType,
+    device::{StringDescriptors, UsbVidPid},
 };
-use usbd_uac2::UsbIsochronousFeedback;
+use usbd_uac2::TerminalConfig;
 use usbd_uac2::{
-    self, AudioClassConfig, RangeEntry, TerminalConfig, UsbAudioClass, UsbAudioClockImpl, UsbSpeed,
-    constants::{FunctionCode, TerminalType},
-    descriptors::{ChannelConfig, ClockType, FormatType1, LockDelay},
+    self, AudioHandler, ClockSource, RangeEntry, UsbAudioClassConfig, UsbIsochronousFeedback,
+    UsbSpeed, constants::FunctionCode, descriptors::ClockType,
 };

 use crate::dma::DmaRing;
@@ -50,43 +53,35 @@ mod dma;
 mod hw;
 mod wm8904;

+// pid.codes test IDs
+const USB_VID: u16 = 0x1209;
+const USB_PID: u16 = 0x0001;
+const USB_MANUFACTURER: &str = "usbd_uac2";
+const USB_PRODUCT: &str = "DMA example device";
+
 const CODEC_I2C_ADDR: u8 = 0b0011010;
 const MCLK_FREQ: u32 = 12288000;
+
 const SAMPLE_RATE: u32 = 96000;
+const USB_FRAME_RATE: u32 = if cfg!(feature = "usbhs") { 8000 } else { 1000 };
+
 //latency ≈ (current_fill × FRAMES_PER_SLOT)
 //              + FRAMES_PER_SLOT/2 - average DMA transfer position
 //              + 8 - FIFO depth @ 32-bit samples
+// with example values, ~2.3ms
 const BYTES_PER_SAMPLE: usize = 4; // 32 bit samples
 const BYTES_PER_FRAME: usize = BYTES_PER_SAMPLE * 2; // 2 channels
 const FRAMES_PER_SLOT: usize = SAMPLE_RATE as usize / 2000; // run the DMA at 2khz
-const SLOT_SIZE_BYTES: usize = FRAMES_PER_SLOT * BYTES_PER_FRAME; // run the DMA at 2khz
-const N_SLOTS: usize = 32;
-const FILL_TARGET: i32 = (FRAMES_PER_SLOT * N_SLOTS) as i32 / 2;
+const BYTES_PER_SLOT: usize = FRAMES_PER_SLOT * BYTES_PER_FRAME;
+const N_SLOTS: usize = 8;
+const FILL_TARGET_BYTES: i32 = (BYTES_PER_SLOT * N_SLOTS) as i32 / 2;

-struct Clock {}
-impl Clock {
-    const RATES: [RangeEntry<u32>; 1] = [RangeEntry::new_fixed(SAMPLE_RATE)];
-}
-impl UsbAudioClockImpl for Clock {
-    const CLOCK_TYPE: usbd_uac2::descriptors::ClockType = ClockType::InternalFixed;
-    const SOF_SYNC: bool = false;
-    fn get_sample_rate(&self) -> u32 {
-        Clock::RATES[0].min
-    }
-    fn get_rates(
-        &self,
-    ) -> core::result::Result<&[usbd_uac2::RangeEntry<u32>], usbd_uac2::UsbAudioClassError> {
-        Ok(&Clock::RATES)
-    }
-    fn get_clock_validity(&self) -> core::result::Result<bool, usbd_uac2::UsbAudioClassError> {
-        Ok(true)
-    }
-}
+const LOG_PERIOD: u32 = 1000;

-static DMA_RING: StaticCell<DmaRing<N_SLOTS, SLOT_SIZE_BYTES>> = StaticCell::new();
-static mut DMA_RING_REF: Option<&'static DmaRing<N_SLOTS, SLOT_SIZE_BYTES>> = None;
+static DMA_RING: StaticCell<DmaRing<N_SLOTS, BYTES_PER_SLOT>> = StaticCell::new();
+static mut DMA_RING_REF: Option<&'static DmaRing<N_SLOTS, BYTES_PER_SLOT>> = None;
 #[inline]
-fn dma_ring() -> &'static DmaRing<N_SLOTS, SLOT_SIZE_BYTES> {
+fn dma_ring() -> &'static DmaRing<N_SLOTS, BYTES_PER_SLOT> {
    unsafe { DMA_RING_REF.unwrap() }
 }

@@ -125,13 +120,15 @@ struct Audio<'a, const N: usize, const MAX_SLOT_BYTES: usize> {
    running: AtomicBool,
    i2s: I2sTx,
    dma: &'a DmaRing<N, MAX_SLOT_BYTES>,
+    log_counter: u32,
 }
 impl<const N: usize, const MAX_SLOT_BYTES: usize> Audio<'_, N, MAX_SLOT_BYTES> {
-    fn start(&self) {
+    const RATES: [RangeEntry<u32>; 1] = [RangeEntry::new_fixed(SAMPLE_RATE)];
+    fn start(&mut self) {
        red_led().off(); // clear any dma error
        self.running.store(false, Ordering::Relaxed);

-        defmt::info!("playback starting (DMA)");
+        defmt::info!("playback armed (DMA)");

        let i2s = &self.i2s.i2s;
        i2s.fifotrig
@@ -150,15 +147,15 @@ impl<const N: usize, const MAX_SLOT_BYTES: usize> Audio<'_, N, MAX_SLOT_BYTES> {
        // If we don't disable interrupts while stopped, we will underflow constantly and continuously refill the fifo with 0s
        // We could actually stop the I2S here, but sometimes that makes the DAC misbehave. The peripheral is configured to send
        // 0s when the FIFO is empty, so this is fine.
+        pac::NVIC::mask(pac::Interrupt::DMA0);
        self.running.store(false, Ordering::Relaxed);
        dma_ring().stop();
        defmt::info!("playback stopped");
-        pac::NVIC::mask(pac::Interrupt::DMA0);
        green_led().off();
        blue_led().off();
    }
 }
-impl<const N: usize, const MAX_SLOT_BYTES: usize, B: bus::UsbBus> UsbAudioClass<'_, B>
+impl<const N: usize, const MAX_SLOT_BYTES: usize, B: bus::UsbBus> AudioHandler<'_, B>
    for Audio<'_, N, MAX_SLOT_BYTES>
 {
    fn alternate_setting_changed(&mut self, _terminal: usb_device::UsbDirection, alt_setting: u8) {
@@ -174,7 +171,8 @@ impl<const N: usize, const MAX_SLOT_BYTES: usize, B: bus::UsbBus> UsbAudioClass<
        ep: &usb_device::endpoint::Endpoint<'_, B, usb_device::endpoint::Out>,
    ) {
        // Buffer must fit 125us of audio data (based on how `usbd_uac2` sets up the descriptors).
-        let mut buf = [0; SAMPLE_RATE.div_ceil(8000) as usize * BYTES_PER_FRAME];
+        // Buffer must have room for one additional frame in case the host clock runs slower than the device.
+        let mut buf = [0; (SAMPLE_RATE.div_ceil(USB_FRAME_RATE) + 1) as usize * BYTES_PER_FRAME];

        let len = match ep.read(&mut buf) {
            Ok(len) => len,
@@ -199,61 +197,90 @@ impl<const N: usize, const MAX_SLOT_BYTES: usize, B: bus::UsbBus> UsbAudioClass<
        }
        // If we're not running yet, wait until we reach 50% full then enable DMA requests
        if !self.running.load(Ordering::Relaxed) && self.dma.fill_slots() >= (N_SLOTS / 2) {
-            defmt::debug!(
-                "buffer has {} slots, start dma transfers",
+            defmt::info!(
+                "buffer warmed ({} slots) starting playback",
                self.dma.fill_slots()
            );
            self.dma.run();
            self.running.store(true, Ordering::Relaxed)
        }
    }
+    fn audio_data_tx(
+        &mut self,
+        _ep: &usb_device::endpoint::Endpoint<'_, B, usb_device::endpoint::In>,
+    ) {
+    }

-    /// Provide rate feedback to the host, so that it doesn't over- or underflow
-    /// the buffer. Proportional-only control is stable with normal hosts,
-    /// adding an I term with proper tuning (quite weak) would stabilize the
-    /// rate reported to the host but is not necessary for basic playback.
+    /// Provide rate feedback to the host. P-only is stable and works fine, with
+    /// most hosts. The host can either filter it internally or treat it
+    /// instantaneously and send more data specifically when the error gets
+    /// large; we will absorb reasonable clock drifts with our ring buffer.
    fn feedback(&mut self, nominal_rate: UsbIsochronousFeedback) -> Option<UsbIsochronousFeedback> {
-        const MAX_CORRECTION: i32 = 1 << 10; // ~1.6%
+        // Don't want to signal an absurd rate when not consuming; let the
+        // buffer fill before starting feedback.
+        if !self.running.load(Ordering::Acquire) {
+            return Some(nominal_rate);
+        }

-        let produced_bytes = self.dma.produced_bytes.load(Ordering::Acquire);
+        let produced_bytes = self.dma.produced_bytes();
        let consumed_bytes = self.dma.consumed_bytes();

-        let valid = produced_bytes >= consumed_bytes; // else we are in underrun condition
+        if produced_bytes < consumed_bytes || produced_bytes == 0 {
+            defmt::error!("[fb] dma underrun detected!");
+            red_led().on();
+            return Some(nominal_rate);
+        }

-        let fill_frames = if valid {
-            (produced_bytes - consumed_bytes) as i32 / BYTES_PER_FRAME as i32
-        } else {
-            // we will emit a canonical error in the DMA ISR
-            defmt::debug!("[fb] dma underrun detected");
-            0
-        };
-
-        let mut error = fill_frames - FILL_TARGET;
-        error = error.clamp(-32, 32); // avoid huge spikes
-
-        let p = error * 256;
-        let i = 0; // placeholder
-
-        let correction = -(p + i);
+        let current_bytes = (produced_bytes - consumed_bytes) as i32;
+        // normalize error wrt. frame size etc.
+        let error_permille = ((current_bytes - FILL_TARGET_BYTES) * 1000) / FILL_TARGET_BYTES;

        let nominal_v = nominal_rate.to_u32_12_13() as i32;

-        let mut v = nominal_v + correction;
+        // 0.2% which is a huge clock error
+        let max_allowed_deviation = nominal_v / 500;

-        v = v.clamp(nominal_v - MAX_CORRECTION, nominal_v + MAX_CORRECTION);
+        let p_term = -(error_permille * nominal_v) / 256000; // this works reasonably well to keep the buffer
+        let i_term = 0; // placeholder

-        defmt::debug!(
-            "valid:{} fill:{} err:{} fb:{=u32:x}",
-            valid,
-            fill_frames,
-            error,
+        let mut v = nominal_v + p_term + i_term;
+        v = v.clamp(
+            nominal_v - max_allowed_deviation,
+            nominal_v + max_allowed_deviation,
+        );
+        self.log_counter += 1;
+        if self.log_counter.is_multiple_of(LOG_PERIOD) {
+            defmt::info!(
+                "fill:{}% err_pm:{} p:{} i:{} fb_delta:{} fb:{=u32:x}",
+                (current_bytes * 100) / (N_SLOTS * BYTES_PER_SLOT) as i32,
+                error_permille,
+                p_term,
+                i_term,
+                v - nominal_v,
                v as u32
            );
+        }

        Some(UsbIsochronousFeedback::new(v as u32))
    }
 }

+impl<const N: usize, const MAX_SLOT_BYTES: usize> ClockSource for Audio<'_, N, MAX_SLOT_BYTES> {
+    const CLOCK_TYPE: usbd_uac2::descriptors::ClockType = ClockType::InternalFixed;
+    const SOF_SYNC: bool = false;
+    fn sample_rate(&self) -> u32 {
+        Self::RATES[0].min
+    }
+    fn sample_rates(
+        &self,
+    ) -> core::result::Result<&[usbd_uac2::RangeEntry<u32>], usbd_uac2::UsbAudioClassError> {
+        Ok(&Self::RATES)
+    }
+    fn clock_validity(&self) -> core::result::Result<bool, usbd_uac2::UsbAudioClassError> {
+        Ok(true)
+    }
+}
+
 #[entry]
 fn main() -> ! {
    let hal = hal::new();
@@ -277,7 +304,7 @@ fn main() -> ! {
        pins::Pio1_20::take().unwrap().into_i2c4_scl_pin(&mut iocon),
        pins::Pio1_21::take().unwrap().into_i2c4_sda_pin(&mut iocon),
    );
-    // We can initialize and iocon these, but there is no peripheral, so they do not get used
+    // We can initialize and iocon these, but there is no peripheral driver, so they do not get used
    let _codec_i2s_pins = (
        pins::Pio0_21::take().unwrap().into_spi7_sck_pin(&mut iocon),
        pins::Pio0_20::take().unwrap().into_i2s7_sda_pin(&mut iocon),
@@ -286,18 +313,16 @@ fn main() -> ! {
    );

    debug!("clocks");
-    // Run the system clock at 96MHz. The lpc55-hal will run it from the FRO. But we won't actually use these clocks, we just need the guards...
    let clocks = hal::ClockRequirements::default()
        .system_frequency(96.MHz())
        .configure(&mut anactrl, &mut pmc, &mut syscon)
        .unwrap();
-    let mut _delay_timer = Timer::new(
+    let mut usb_delay_timer = Timer::new(
        hal.ctimer
            .0
            .enabled(&mut syscon, clocks.support_1mhz_fro_token().unwrap()),
    );
-    // Start PLL1 at 150MHz as main system clock
-    hw::init_sys_pll1();
+
    // Start PLL0 at 24.576MHz as the audio clock. The FRO cannot evenly divide
    // any common audio frequencies and is not particularly stable anyway.
    hw::init_audio_pll();
@@ -326,7 +351,7 @@ fn main() -> ! {
            &mut anactrl,
            &mut pmc,
            &mut syscon,
-            &mut _delay_timer,
+            &mut usb_delay_timer,
            clocks.support_usbhs_token().unwrap(),
        ),
    );
@@ -348,48 +373,30 @@ fn main() -> ! {

    defmt::debug!("dma init");
    let i2s_dma_addr = &i2s_peripheral.i2s.fifowr as *const _ as *mut u32;
-    let dma = DmaRing::<32, SLOT_SIZE_BYTES>::new(hal.dma.release(), &mut syscon, i2s_dma_addr, 4)
+    let dma =
+        DmaRing::<N_SLOTS, BYTES_PER_SLOT>::new(hal.dma.release(), &mut syscon, i2s_dma_addr, 4)
            .unwrap();
    let dma_ref = DMA_RING.init(dma);
    unsafe { DMA_RING_REF = Some(dma_ref) };

-    let mut clock = Clock {};
    let mut audio = Audio {
        i2s: i2s_peripheral,
        dma: dma_ring(),
        running: AtomicBool::new(false),
+        log_counter: 0,
    };
    defmt::debug!("usb init");
-    let config = AudioClassConfig::new(usb_speed, FunctionCode::Other, &mut clock, &mut audio)
-        .with_output_config(TerminalConfig::new(
-            4,
-            1,
-            2,
-            FormatType1 {
-                bit_resolution: 32,
-                bytes_per_sample: 4,
-            },
-            TerminalType::ExtLineConnector,
-            ChannelConfig::default_chans(2),
-            IsochronousSynchronizationType::Asynchronous,
-            LockDelay::Milliseconds(10),
-            None,
-        ));
-
+    let config = UsbAudioClassConfig::new(usb_speed, FunctionCode::IoBox, &mut audio)
+        .with_output_config(TerminalConfig::builder().base_id(2).build());
    let mut uac2 = config.build(&usb_bus).unwrap();

-    let mut usb_dev = UsbDeviceBuilder::new(&usb_bus, UsbVidPid(0x1209, 0xcc1d))
-        .composite_with_iads()
+    let mut usb_dev = usbd_uac2::builder(&usb_bus, UsbVidPid(USB_VID, USB_PID))
        .strings(&[StringDescriptors::default()
-            .manufacturer("Generic")
-            .product("usbd_uac2 device")
-            .serial_number("123456789")])
+            .manufacturer(USB_MANUFACTURER)
+            .product(USB_PRODUCT)])
        .unwrap()
-        .max_packet_size_0(64)
+        .max_packet_size_0(64) // Required to be 64 on HS, allowed on FS
        .unwrap()
-        .device_class(0xef)
-        .device_sub_class(0x02)
-        .device_protocol(0x01)
        .build();

    defmt::info!("main loop");
@@ -1,10 +1,3 @@
-[target.thumbv8m.main-none-eabi]
-rustflags = [
-  "-C", "link-arg=-Tlink.x",
-  "-C", "link-arg=-Tdefmt.x",
-  "-C", "debug-assertions",
-]
-
 [target.thumbv8m.main-none-eabihf]
 rustflags = [
  "-C", "link-arg=-Tlink.x",
@@ -16,4 +9,4 @@ rustflags = [
 target = "thumbv8m.main-none-eabihf"

 [env]
-DEFMT_LOG = "info"
+DEFMT_LOG = "off"
@@ -2,6 +2,15 @@
 # It is not intended for manual editing.
 version = 4

+[[package]]
+name = "aho-corasick"
+version = "1.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddd31a130427c27518df266943a5308ed92d4b226cc639f5a8f1002816174301"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "atomic-polyfill"
 version = "1.0.3"
@@ -26,6 +35,17 @@ dependencies = [
 "rustc_version 0.2.3",
 ]

+[[package]]
+name = "bbqueue"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68917624e17aad88607cb5a5936f6da9b607c48c711e4e9ed101e7189aed28c2"
+dependencies = [
+ "const-init",
+ "critical-section",
+ "maitake-sync",
+]
+
 [[package]]
 name = "bitfield"
 version = "0.13.2"
@@ -63,6 +83,22 @@ dependencies = [
 "embedded-io",
 ]

+[[package]]
+name = "cc"
+version = "1.2.61"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d16d90359e986641506914ba71350897565610e87ce0ad9e6f28569db3dd5c6d"
+dependencies = [
+ "find-msvc-tools",
+ "shlex",
+]
+
+[[package]]
+name = "cfg-if"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
+
 [[package]]
 name = "cipher"
 version = "0.4.4"
@@ -73,6 +109,22 @@ dependencies = [
 "inout",
 ]

+[[package]]
+name = "const-init"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4bd422bfb4f24a97243f60b6a4443e63d810c925d8da4bb2d8fde26a7c1d57ec"
+
+[[package]]
+name = "cordyceps"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "688d7fbb8092b8de775ef2536f36c8c31f2bc4006ece2e8d8ad2d17d00ce0a2a"
+dependencies = [
+ "loom",
+ "tracing",
+]
+
 [[package]]
 name = "cortex-m"
 version = "0.7.7"
@@ -214,6 +266,27 @@ dependencies = [
 "num",
 ]

+[[package]]
+name = "find-msvc-tools"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5baebc0774151f905a1a2cc41989300b1e6fbb29aff0ceffa1064fdd3088d582"
+
+[[package]]
+name = "generator"
+version = "0.8.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "52f04ae4152da20c76fe800fa48659201d5cf627c5149ca0b707b69d7eef6cf9"
+dependencies = [
+ "cc",
+ "cfg-if",
+ "libc",
+ "log",
+ "rustversion",
+ "windows-link",
+ "windows-result",
+]
+
 [[package]]
 name = "generic-array"
 version = "0.14.7"
@@ -275,16 +348,6 @@ dependencies = [
 "stable_deref_trait",
 ]

-[[package]]
-name = "heapless"
-version = "0.9.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "25ba4bd83f9415b58b4ed8dc5714c76e626a105be4646c02630ad730ad3b5aa4"
-dependencies = [
- "hash32 0.3.1",
- "stable_deref_trait",
-]
-
 [[package]]
 name = "inout"
 version = "0.1.4"
@@ -294,6 +357,18 @@ dependencies = [
 "generic-array 0.14.7",
 ]

+[[package]]
+name = "lazy_static"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
+
+[[package]]
+name = "libc"
+version = "0.2.186"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68ab91017fe16c622486840e4c83c9a37afeff978bd239b5293d61ece587de66"
+
 [[package]]
 name = "lock_api"
 version = "0.4.14"
@@ -320,9 +395,23 @@ dependencies = [
 "log",
 ]

+[[package]]
+name = "loom"
+version = "0.7.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "419e0dc8046cb947daa77eb95ae174acfbddb7673b4151f56d1eed8e93fbfaca"
+dependencies = [
+ "cfg-if",
+ "generator",
+ "scoped-tls",
+ "tracing",
+ "tracing-subscriber",
+]
+
 [[package]]
 name = "lpc55-hal"
 version = "0.5.0"
+source = "git+https://github.com/ktims/lpc55-hal?branch=main#8dfefd62aff4abd2de535f23107812dda68437be"
 dependencies = [
 "block-buffer",
 "cipher",
@@ -354,23 +443,51 @@ dependencies = [
 name = "lpc55s28-evk"
 version = "0.1.0"
 dependencies = [
+ "bbqueue",
 "cortex-m",
 "cortex-m-rt",
 "defmt 1.0.1",
 "defmt-rtt",
 "embedded-hal 1.0.0",
 "embedded-io",
- "heapless 0.9.3",
 "log-to-defmt",
 "lpc55-hal",
- "nb 1.1.0",
- "panic-halt",
 "panic-probe",
- "static_cell",
 "usb-device",
 "usbd-uac2",
 ]

+[[package]]
+name = "maitake-sync"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3d77c365d697828821727b9bc09e6bc3c518b8c63804e79e1be5a5ae091a7c5f"
+dependencies = [
+ "cordyceps",
+ "critical-section",
+ "loom",
+ "mutex-traits",
+ "mycelium-bitfield",
+ "pin-project",
+ "portable-atomic",
+ "tracing",
+]
+
+[[package]]
+name = "matchers"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d1525a2a28c7f4fa0fc98bb91ae755d1e2d1505079e05539e35bc876b5d65ae9"
+dependencies = [
+ "regex-automata",
+]
+
+[[package]]
+name = "memchr"
+version = "2.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f8ca58f447f06ed17d5fc4043ce1b10dd205e060fb3ce5b979b8ed8e59ff3f79"
+
 [[package]]
 name = "modular-bitfield"
 version = "0.13.1"
@@ -392,6 +509,18 @@ dependencies = [
 "syn",
 ]

+[[package]]
+name = "mutex-traits"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3929f2b5633d29cf7b6624992e5f3c1e9334f1193423e12d17be4faf678cde3f"
+
+[[package]]
+name = "mycelium-bitfield"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "24e0cc5e2c585acbd15c5ce911dff71e1f4d5313f43345873311c4f5efd741cc"
+
 [[package]]
 name = "nb"
 version = "0.1.3"
@@ -407,6 +536,15 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8d5439c4ad607c3c23abf66de8c8bf57ba8adcd1f129e699851a6e43935d339d"

+[[package]]
+name = "nu-ansi-term"
+version = "0.50.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7957b9740744892f114936ab4a57b3f487491bbeafaf8083688b16841a4240e5"
+dependencies = [
+ "windows-sys",
+]
+
 [[package]]
 name = "num"
 version = "0.3.1"
@@ -470,10 +608,10 @@ dependencies = [
 ]

 [[package]]
-name = "panic-halt"
-version = "1.0.0"
+name = "once_cell"
+version = "1.21.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a513e167849a384b7f9b746e517604398518590a9142f4846a32e3c2a4de7b11"
+checksum = "9f7c3e4beb33f85d45ae3e3a1792185706c8e16d043238c593331cc7cd313b50"

 [[package]]
 name = "panic-probe"
@@ -485,6 +623,32 @@ dependencies = [
 "defmt 1.0.1",
 ]

+[[package]]
+name = "pin-project"
+version = "1.1.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cbf0d9e68100b3a7989b4901972f265cd542e560a3a8a724e1e20322f4d06ce9"
+dependencies = [
+ "pin-project-internal",
+]
+
+[[package]]
+name = "pin-project-internal"
+version = "1.1.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a990e22f43e84855daf260dded30524ef4a9021cc7541c26540500a50b624389"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "pin-project-lite"
+version = "0.2.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a89322df9ebe1c1578d689c92318e070967d1042b512afbe49518723f4e6d5cd"
+
 [[package]]
 name = "portable-atomic"
 version = "1.13.1"
@@ -537,6 +701,23 @@ version = "0.6.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"

+[[package]]
+name = "regex-automata"
+version = "0.4.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6e1dd4122fc1595e8162618945476892eefca7b88c52820e74af6262213cae8f"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc897dd8d9e8bd1ed8cdad82b5966c3e0ecae09fb1907d58efaa013543185d0a"
+
 [[package]]
 name = "rustc_version"
 version = "0.2.3"
@@ -561,6 +742,12 @@ version = "1.0.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b39cdef0fa800fc44525c84ccb54a029961a8215f9619753635a9c0d2538d46d"

+[[package]]
+name = "scoped-tls"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e1cf6437eb19a8f4a6cc0f7dca544973b0b78843adbfeb3683d1a94a0024a294"
+
 [[package]]
 name = "scopeguard"
 version = "1.2.0"
@@ -588,6 +775,27 @@ version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"

+[[package]]
+name = "sharded-slab"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f40ca3c46823713e0d4209592e8d6e826aa57e928f09752619fc696c499637f6"
+dependencies = [
+ "lazy_static",
+]
+
+[[package]]
+name = "shlex"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
+
+[[package]]
+name = "smallvec"
+version = "1.15.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "67b1b7a3b5fe4f1376887184045fcf45c69e92af734b7aaddc05fb777b6fbd03"
+
 [[package]]
 name = "spin"
 version = "0.9.8"
@@ -609,15 +817,6 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"

-[[package]]
-name = "static_cell"
-version = "2.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0530892bb4fa575ee0da4b86f86c667132a94b74bb72160f58ee5a4afec74c23"
-dependencies = [
- "portable-atomic",
-]
-
 [[package]]
 name = "syn"
 version = "2.0.117"
@@ -649,6 +848,76 @@ dependencies = [
 "syn",
 ]

+[[package]]
+name = "thread_local"
+version = "1.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f60246a4944f24f6e018aa17cdeffb7818b76356965d03b07d6a9886e8962185"
+dependencies = [
+ "cfg-if",
+]
+
+[[package]]
+name = "tracing"
+version = "0.1.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "63e71662fa4b2a2c3a26f570f037eb95bb1f85397f3cd8076caed2f026a6d100"
+dependencies = [
+ "pin-project-lite",
+ "tracing-attributes",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-attributes"
+version = "0.1.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7490cfa5ec963746568740651ac6781f701c9c5ea257c58e057f3ba8cf69e8da"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "tracing-core"
+version = "0.1.36"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "db97caf9d906fbde555dd62fa95ddba9eecfd14cb388e4f491a66d74cd5fb79a"
+dependencies = [
+ "once_cell",
+ "valuable",
+]
+
+[[package]]
+name = "tracing-log"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee855f1f400bd0e5c02d150ae5de3840039a3f54b025156404e34c23c03f47c3"
+dependencies = [
+ "log",
+ "once_cell",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-subscriber"
+version = "0.3.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cb7f578e5945fb242538965c2d0b04418d38ec25c79d160cd279bf0731c8d319"
+dependencies = [
+ "matchers",
+ "nu-ansi-term",
+ "once_cell",
+ "regex-automata",
+ "sharded-slab",
+ "smallvec",
+ "thread_local",
+ "tracing",
+ "tracing-core",
+ "tracing-log",
+]
+
 [[package]]
 name = "typenum"
 version = "1.20.0"
@@ -684,6 +953,12 @@ dependencies = [
 "usb-device",
 ]

+[[package]]
+name = "valuable"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ba73ea9cf16a25df0c8caa16c51acb937d5712a8429db78a3ee29d5dcacd3a65"
+
 [[package]]
 name = "vcell"
 version = "0.1.3"
@@ -710,3 +985,27 @@ checksum = "de437e2a6208b014ab52972a27e59b33fa2920d3e00fe05026167a1c509d19cc"
 dependencies = [
 "vcell",
 ]
+
+[[package]]
+name = "windows-link"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
+
+[[package]]
+name = "windows-result"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7781fa89eaf60850ac3d2da7af8e5242a5ea78d1a11c49bf2910bb5a73853eb5"
+dependencies = [
+ "windows-link",
+]
+
+[[package]]
+name = "windows-sys"
+version = "0.61.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
+dependencies = [
+ "windows-link",
+]
@@ -2,6 +2,7 @@
 name = "lpc55s28-evk"
 version = "0.1.0"
 edition = "2024"
+publish = false

 [features]
 default = ["usbhs"]
@@ -9,24 +10,16 @@ usbfs = []
 usbhs = []

 [dependencies]
+bbqueue = "0.7.0"
 cortex-m = { version = "0.7.7", features = ["critical-section-single-core"] }
 cortex-m-rt = "0.7.5"
 defmt = "1.0.1"
 defmt-rtt = "1.1.0"
 embedded-hal = "1.0.0"
 embedded-io = "0.7.1"
-heapless = "0.9.3"
 log-to-defmt = "0.1.0"
-lpc55-hal = { version = "0.5.0", path = "../lpc55-hal" }
-nb = "1.1.0"
-panic-halt = "1.0.0"
 panic-probe = { version = "1.0.0", features = ["print-defmt"] }
-static_cell = "2.1.1"
-usb-device = "0.3"
-usbd-uac2 = { version = "0.1.0", path = "../..", features = ["defmt"]}
-
-[profile.release]
-opt-level = "z"
-lto = true
-debug = true
-codegen-units = 1
+# Includes update to usb-device 0.3, fix for isochronous and smaller critical sections
+lpc55-hal = { git = "https://github.com/ktims/lpc55-hal", branch = "main" }
+usb-device.workspace = true
+usbd-uac2 = { workspace = true, features = ["defmt"] }
@@ -0,0 +1,5 @@
+// Find the actual path of memory.x and add it to link search, required for building in workspace
+fn main() {
+    let manifest_dir = std::env::var("CARGO_MANIFEST_DIR").unwrap();
+    println!("cargo:rustc-link-search={}", manifest_dir);
+}
@@ -1,8 +1,20 @@
 //! Contains hardware setup unrelated to Usb Audio Class implementation

 use crate::Syscon;
+use crate::hal;
 use crate::{MCLK_FREQ, SAMPLE_RATE, pac};
+
+use core::cell::UnsafeCell;
+use core::mem::MaybeUninit;
 use defmt::debug;
+use hal::{
+    Enabled, Iocon, Pin,
+    drivers::pins,
+    peripherals::syscon::{ClockControl, ResetControl},
+    traits::wg::digital::v2::{OutputPin, ToggleableOutputPin},
+    typestates::pin::{gpio::direction::Output, state::Gpio},
+};
+
 pub(crate) struct PllConstants {
    pub m: u16,   // 1-65535
    pub n: u8,    // 1-255
@@ -79,7 +91,7 @@ pub(crate) fn init_audio_pll() {
        .xo32m_ctrl
        .modify(|_, w| w.enable_system_clk_out().enable());

-    debug!("init pll: {}", AUDIO_PLL);
+    debug!("init pll0: {}", AUDIO_PLL);
    pmc.pdruncfg0
        .modify(|_, w| w.pden_pll0().poweredoff().pden_pll0_sscg().poweredoff());
    syscon.pll0clksel.write(|w| w.sel().enum_0x1()); // clk_in
@@ -132,18 +144,35 @@ pub(crate) fn init_audio_pll() {
    debug!("pll0 locked after {} tries", i);
 }

-pub struct I2sTx {
-    pub i2s: pac::I2S7,
+pub struct I2sHandles {
+    pub tx: pac::I2S7,
+    pub rx: pac::I2S6,
 }

-pub fn init_i2s(mut fc7: pac::FLEXCOMM7, i2s7: pac::I2S7, syscon: &mut Syscon) -> I2sTx {
+pub fn init_i2s(
+    fc7: pac::FLEXCOMM7,
+    i2s7: pac::I2S7,
+    fc6: pac::FLEXCOMM6,
+    i2s6: pac::I2S6,
+    syscon: &mut Syscon,
+) -> I2sHandles {
    defmt::debug!("init i2s");
    // Enable BOTH
-    syscon.reset(&mut fc7);
-    syscon.enable_clock(&mut fc7);
-
-    unsafe {
-        pac::IOCON::ptr().as_ref().unwrap().pio1_31.modify(|_, w| {
+    fc7.clear_reset(syscon);
+    fc7.enable_clock(syscon);
+    fc6.clear_reset(syscon);
+    fc6.enable_clock(syscon);
+    {
+        let sc = unsafe { pac::SYSCON::ptr().as_ref().unwrap() };
+        let ioc = unsafe { pac::IOCON::ptr().as_ref().unwrap() };
+        // MCLK source
+        //
+        sc.mclkclksel.write(|w| w.sel().enum_0x1()); // PLL0
+        // MCLK div
+        sc.mclkdiv
+            .write(|w| unsafe { w.div().bits(1).halt().run().reset().released() }); // div by 2 = PLL0 fout / 2 = 12.288MHz, max for WM8904 @ 96k
+        // MCLK out config
+        ioc.pio1_31.modify(|_, w| {
            w.func()
                .alt1()
                .mode()
@@ -157,57 +186,65 @@ pub fn init_i2s(mut fc7: pac::FLEXCOMM7, i2s7: pac::I2S7, syscon: &mut Syscon) -
                .od()
                .normal()
        });
-        pac::SYSCON::ptr()
-            .as_ref()
-            .unwrap()
-            .fcclksel7()
-            .modify(|_, w| w.sel().enum_0x5()); // MCLK
-        pac::SYSCON::ptr()
-            .as_ref()
-            .unwrap()
-            .mclkclksel
-            .modify(|_, w| w.sel().enum_0x1()); // PLL0
-        pac::SYSCON::ptr()
-            .as_ref()
-            .unwrap()
-            .mclkdiv
-            .modify(|_, w| w.div().bits(1).halt().run().reset().released()); // div by 2 = PLL0 fout / 2 = 12.288MHz, max for WM8904 @ 96k
-        pac::SYSCON::ptr()
-            .as_ref()
-            .unwrap()
-            .mclkio
-            .modify(|_, w| w.mclkio().output());
-    };
+        // FC7 clock
+        sc.fcclksel7().modify(|_, w| w.sel().enum_0x5()); // MCLK
+        // FC6 clock
+        sc.fcclksel6().modify(|_, w| w.sel().enum_0x5()); // MCLK
+        // MCLK out
+        sc.mclkio.modify(|_, w| w.mclkio().output());
+
+        // Enable clock for sysctl, it's not mapped into Peripherals
+        sc.ahbclkctrlset[2].write(|w| unsafe { w.bits(1 << 15) });
+        while sc.ahbclkctrl2.read().sysctl().is_disable() {}
+        let sysctrl = unsafe { pac::SYSCTL::ptr().as_ref().unwrap() };
+        sysctrl.sharedctrlset[0].write(|w| w.sharedscksel().flexcomm7().sharedwssel().flexcomm7()); // FC7 drives shared SCK, WS
+        sysctrl.fcctrlsel[7].write(|w| {
+            w.sckinsel()
+                .shared_set0_i2s_signals()
+                .wsinsel()
+                .shared_set0_i2s_signals()
+        }); // FC7 uses shared set
+        sysctrl.fcctrlsel[6].write(|w| {
+            w.sckinsel()
+                .shared_set0_i2s_signals()
+                .wsinsel()
+                .shared_set0_i2s_signals()
+        });
+
+        // for _ in 0..1000 {
+        //     cortex_m::asm::nop();
+        // }
+    }

    // Select I2S TX function
    fc7.pselid.write(|w| w.persel().i2s_transmit());
+    // Select I2S RX function
+    fc6.pselid.write(|w| w.persel().i2s_receive());

-    let regs = i2s7;
+    let out_regs = i2s7;
+    let in_regs = i2s6;

    // Enable TX FIFO only
-    regs.fifocfg.modify(|_, w| {
+    out_regs.fifocfg.write(|w| {
        w.enabletx()
            .enabled()
-            .enablerx()
-            .disabled()
-            .dmatx()
-            .disabled()
-            .txi2se0()
+            .txi2se0() // transmit 0s when empty - only supported option for 32b data
            .zero()
+            .emptytx() // reset the tx queue
+            .set_bit()
    });

-    // Flush
-    regs.fifocfg.modify(|_, w| w.emptytx().set_bit());
-
-    regs.cfg2
-        .modify(|_, w| unsafe { w.position().bits(0).framelen().bits(63) }); // framelen = 64
+    out_regs
+        .cfg2
+        .write(|w| unsafe { w.position().bits(0).framelen().bits(63) }); // framelen = 64

    let bclk_div = (MCLK_FREQ / SAMPLE_RATE / 64) as u16;
-    regs.div
-        .modify(|_, w| unsafe { w.div().bits(bclk_div - 1) }); // Clock source is MCLK (12.288MHz) / 4 = 3MHz
+    out_regs
+        .div
+        .write(|w| unsafe { w.div().bits(bclk_div - 1) }); // Clock source is MCLK (12.288MHz) / 4 = 3MHz

-    // Config
-    regs.cfg1.modify(|_, w| unsafe {
+    // TX Config
+    out_regs.cfg1.write(|w| unsafe {
        w.mstslvcfg()
            .normal_master()
            .onechannel()
@@ -222,5 +259,102 @@ pub fn init_i2s(mut fc7: pac::FLEXCOMM7, i2s7: pac::I2S7, syscon: &mut Syscon) -
            .normal()
    });

-    I2sTx { i2s: regs }
+    // Enable RX FIFO only
+    in_regs
+        .fifocfg
+        .write(|w| w.enablerx().enabled().emptyrx().set_bit());
+    in_regs
+        .cfg2
+        .write(|w| unsafe { w.position().bits(0).framelen().bits(63) }); // framelen = 64
+    in_regs.div.write(|w| unsafe { w.div().bits(0) });
+    in_regs.cfg1.write(|w| unsafe {
+        w.mstslvcfg()
+            .normal_slave_mode()
+            .onechannel()
+            .dual_channel()
+            .datalen()
+            .bits(31)
+            .mainenable()
+            .enabled()
+            .mode()
+            .classic_mode()
+            .datapause()
+            .normal()
+    });
+
+    I2sHandles {
+        tx: out_regs,
+        rx: in_regs,
+    }
+}
+
+pub struct SharedLed<T: OutputPin> {
+    inner: UnsafeCell<T>,
+}
+unsafe impl<T: OutputPin> Sync for SharedLed<T> {}
+impl<T: OutputPin> SharedLed<T> {
+    pub fn new(inner: T) -> Self {
+        Self {
+            inner: UnsafeCell::new(inner),
+        }
+    }
+    pub fn on(&self) {
+        unsafe {
+            (*self.inner.get()).set_low().ok();
+        }
+    }
+    pub fn off(&self) {
+        unsafe {
+            (*self.inner.get()).set_high().ok();
+        }
+    }
+}
+impl<T: OutputPin + ToggleableOutputPin> SharedLed<T> {
+    pub fn toggle(&self) {
+        unsafe {
+            (*self.inner.get()).toggle().ok();
+        }
+    }
+}
+
+type RedLed = Pin<pins::Pio1_6, Gpio<Output>>;
+type GreenLed = Pin<pins::Pio1_7, Gpio<Output>>;
+type BlueLed = Pin<pins::Pio1_4, Gpio<Output>>;
+pub static RED_LED: MaybeUninit<SharedLed<RedLed>> = MaybeUninit::uninit();
+pub static GREEN_LED: MaybeUninit<SharedLed<GreenLed>> = MaybeUninit::uninit();
+pub static BLUE_LED: MaybeUninit<SharedLed<BlueLed>> = MaybeUninit::uninit();
+
+pub fn init_leds(iocon: &mut Iocon<Enabled>, gpio: &mut hal::Gpio<Enabled>) {
+    let red_led = SharedLed::new(
+        pins::Pio1_6::take()
+            .unwrap()
+            .into_gpio_pin(iocon, gpio)
+            .into_output_low(),
+    );
+    let green_led = SharedLed::new(
+        pins::Pio1_7::take()
+            .unwrap()
+            .into_gpio_pin(iocon, gpio)
+            .into_output_low(),
+    );
+    let blue_led = SharedLed::new(
+        pins::Pio1_4::take()
+            .unwrap()
+            .into_gpio_pin(iocon, gpio)
+            .into_output_low(),
+    );
+    unsafe {
+        core::ptr::write(RED_LED.as_ptr() as *mut SharedLed<RedLed>, red_led);
+        core::ptr::write(GREEN_LED.as_ptr() as *mut SharedLed<GreenLed>, green_led);
+        core::ptr::write(BLUE_LED.as_ptr() as *mut SharedLed<BlueLed>, blue_led);
+    }
+}
+pub fn red_led() -> &'static SharedLed<RedLed> {
+    unsafe { &*RED_LED.as_ptr() }
+}
+pub fn green_led() -> &'static SharedLed<GreenLed> {
+    unsafe { &*GREEN_LED.as_ptr() }
+}
+pub fn blue_led() -> &'static SharedLed<BlueLed> {
+    unsafe { &*BLUE_LED.as_ptr() }
 }
@@ -1,10 +1,24 @@
-//! Interrupt driven example for the LPCXpresso55S28 demo board
+//! Interrupt driven example for the LPCXpresso55S28 demo board.
 //!
-//! Uses the onboard WM8904 DAC at 48KHz. Clock is generated by PLL0. Simple PI feedback
-//! is implemented.
+//! This is a minimal implementation intended to demonstrate only the minimum
+//! essential implementation, to clarify usage of the class driver.
 //!
-//! Packets from USB are placed a `heapless::spsc::Queue`. They are consumed
-//! by the I2S FIFO in the FLEXCOMM7 interrupt.
+//! Uses the EVK's WM8904 CODEC at 48KHz. Clock is generated by PLL0. Simple
+//! proportional feedback is implemented.
+//!
+//! Packets from USB are placed in a `bbqueue` (a lock free ring buffer). They
+//! are consumed by the I2S FIFO in the FLEXCOMM7 interrupt. This makes the
+//! implementation very sensitive to interrupt::free critical sections (which
+//! are widely used in the USB bus driver), but it works well enough at 48k.
+//!
+//! Audio frames from the CODEC are placed in a separate `bbqueue` from the
+//! FLEXCOMM6 interrupt handler. They're drained out to the USB host in the USB
+//! callback context.
+//!
+//! LEDs:
+//!   - Blue - audio under/overrun - note this toggles a bunch at playback stream startup
+//!   - Red - recording stream running
+//!   - Green - playback stream running
 #![no_main]
 #![no_std]

@@ -17,10 +31,14 @@ fn panic() -> ! {
    panic_probe::hard_fault()
 }

-use core::ptr::null_mut;
-use core::sync::atomic::{AtomicBool, AtomicI32, Ordering};
+use bbqueue::{
+    nicknames::Churrasco,
+    prod_cons::stream::{StreamConsumer, StreamProducer},
+    traits::bbqhdl::BbqHandle,
+};
+use core::sync::atomic::{AtomicU32, Ordering};
 use cortex_m_rt::entry;
-use defmt::debug;
+use defmt::{debug, error, info, warn};
 use defmt_rtt as _;
 use hal::raw as pac;
 use hal::{
@@ -29,186 +47,348 @@ use hal::{
    prelude::*,
    time::Hertz,
 };
-use heapless::spsc::{Consumer, Producer, Queue};
-use lpc55_hal::{self as hal};
+use lpc55_hal as hal;
 use pac::interrupt;
-use static_cell::StaticCell;
 use usb_device::{
    bus::{self},
-    device::{StringDescriptors, UsbDeviceBuilder, UsbVidPid},
-    endpoint::IsochronousSynchronizationType,
+    device::{StringDescriptors, UsbVidPid},
 };
-use usbd_uac2::UsbIsochronousFeedback;
 use usbd_uac2::{
-    self, AudioClassConfig, RangeEntry, TerminalConfig, UsbAudioClass, UsbAudioClockImpl, UsbSpeed,
-    constants::{FunctionCode, TerminalType},
-    descriptors::{ChannelConfig, ClockType, FormatType1, LockDelay},
+    self, AudioHandler, ClockSource, RangeEntry, TerminalConfig, UsbAudioClassConfig,
+    UsbIsochronousFeedback, UsbSpeed, constants::FunctionCode, descriptors::ClockType,
 };

-use crate::hw::I2sTx;
+use crate::hw::{I2sHandles, blue_led, green_led, red_led};

 mod hw;
 mod wm8904;

+// pid.codes test IDs
+const USB_VID: u16 = 0x1209;
+const USB_PID: u16 = 0x0001;
+const USB_MANUFACTURER: &str = "usbd_uac2";
+const USB_PRODUCT: &str = "interrupt example device";
+
 const CODEC_I2C_ADDR: u8 = 0b0011010;
 const FIFO_LENGTH: usize = 256; // frames
 const MCLK_FREQ: u32 = 12288000;
-const SAMPLE_RATE: u32 = 48000; // example implementation runs okay at 48k but not 96k
-type SampleType = (i32, i32);
+const SAMPLE_RATE: u32 = 48000;
+// USB microframe rate
+#[cfg(feature = "usbhs")]
+const USB_FRAME_RATE: usize = 8000;
+#[cfg(feature = "usbfs")]
+const USB_FRAME_RATE: usize = 1000;

-struct Clock {}
-impl Clock {
-    const RATES: [RangeEntry<u32>; 1] = [RangeEntry::new_fixed(SAMPLE_RATE)];
+const BYTES_PER_FRAME: usize = 8;
+const QUEUE_BYTES: usize = FIFO_LENGTH * BYTES_PER_FRAME;
+
+static QUEUE_AUDIO_OUT: Churrasco<QUEUE_BYTES> = Churrasco::new();
+// Used for feedback calculation of current fifo state
+static PRODUCED_OUT: AtomicU32 = AtomicU32::new(0);
+static CONSUMED_OUT: AtomicU32 = AtomicU32::new(0);
+
+static QUEUE_AUDIO_IN: Churrasco<QUEUE_BYTES> = Churrasco::new();
+// Used for feedback calculation of current fifo state
+static PRODUCED_IN: AtomicU32 = AtomicU32::new(0);
+static CONSUMED_IN: AtomicU32 = AtomicU32::new(0);
+
+/// Consume one audio output frame and send it to the I2S FIFO. If there's
+/// insufficient data in the queue, return false without consuming what was
+/// there.
+#[inline]
+fn try_consume_one_frame<T: BbqHandle>(
+    cons: &mut StreamConsumer<T>,
+    i2s: &pac::i2s7::RegisterBlock,
+) -> bool {
+    if let Ok(rgr) = cons.read() {
+        if rgr.len() >= BYTES_PER_FRAME {
+            let l = u32::from_le_bytes(rgr[0..4].try_into().unwrap());
+            let r = u32::from_le_bytes(rgr[4..8].try_into().unwrap());
+
+            i2s.fifowr.write(|w| unsafe { w.bits(l) });
+            i2s.fifowr.write(|w| unsafe { w.bits(r) });
+
+            // consume exactly one frame (8 bytes)
+            rgr.release(BYTES_PER_FRAME);
+            CONSUMED_OUT.fetch_add(BYTES_PER_FRAME as u32, Ordering::Relaxed);
+            return true;
+        } else {
+            // Not enough bytes for a full frame: leave it in the queue.
+            return false;
        }
-impl UsbAudioClockImpl for Clock {
+    }
+    false
+}
+
+/// Produce one audio input from from the I2S FIFO into the queue. If there's no
+/// room in the queue, discard the sample and return false.
+#[inline]
+fn try_produce_one_frame<T: BbqHandle>(
+    prod: &mut StreamProducer<T>,
+    i2s: &pac::i2s6::RegisterBlock,
+) -> bool {
+    let l = i2s.fiford.read().rxdata().bits();
+    let r = i2s.fiford.read().rxdata().bits();
+    if let Ok(mut rgr) = prod.grant_exact(BYTES_PER_FRAME) {
+        unsafe {
+            let wp = rgr.as_mut_ptr();
+            core::ptr::copy_nonoverlapping(&l as *const u32 as *const u8, wp, 4);
+            core::ptr::copy_nonoverlapping(&r as *const u32 as *const u8, wp.add(4), 4);
+        }
+        rgr.commit(BYTES_PER_FRAME * 2);
+        PRODUCED_IN.fetch_add(BYTES_PER_FRAME as u32, Ordering::Relaxed);
+        true
+    } else {
+        // No space in the queue, discard the sample
+        false
+    }
+}
+
+/// I2S TX ISR. Consume frames until the FIFO is full. Only write full frames
+/// (L+R) so we can't desync left/right.
+#[interrupt]
+fn FLEXCOMM7() {
+    let i2s = unsafe { pac::I2S7::ptr().as_ref().unwrap() };
+    // refill until fifo has >6 words
+    let mut cons = QUEUE_AUDIO_OUT.stream_consumer();
+
+    while i2s.fifostat.read().txlvl().bits() <= 6 {
+        if !try_consume_one_frame(&mut cons, i2s) {
+            // No complete frame available: write silence to keep FIFO above threshold
+            // error!("tx queue underflow");
+            blue_led().toggle();
+            i2s.fifowr.write(|w| unsafe { w.bits(0) });
+            i2s.fifowr.write(|w| unsafe { w.bits(0) });
+            break;
+        }
+    }
+}
+
+/// I2S RX ISR. Produce frames until the FIFO is empty (or has only a partial frame).
+#[interrupt]
+fn FLEXCOMM6() {
+    let i2s = unsafe { pac::I2S6::ptr().as_ref().unwrap() };
+    let mut prod = QUEUE_AUDIO_IN.stream_producer();
+    while i2s.fifostat.read().rxlvl().bits() >= 2 {
+        if !try_produce_one_frame(&mut prod, i2s) {
+            blue_led().toggle();
+            // error!("rx queue overflow");
+            break;
+        }
+    }
+}
+
+/// Storage for Audio Class implementation state
+struct Audio<T: BbqHandle> {
+    i2s: I2sHandles,
+    producer: StreamProducer<T>,
+    consumer: StreamConsumer<T>,
+}
+impl<T: BbqHandle> Audio<T> {
+    const RATES: [RangeEntry<u32>; 1] = [RangeEntry::new_fixed(SAMPLE_RATE)];
+    /// Start audio playback. Clear anything in the FIFO, enable interrupts.
+    fn start_audio_out(&self) {
+        info!("playback starting, enabling interrupts");
+        self.i2s.tx.fifocfg.modify(|_, w| w.emptytx().set_bit());
+        self.i2s.tx.fifointenclr.write(|w| w.txlvl().set_bit());
+        // TX FIFO trigger threshold = <= 6 entries
+        self.i2s
+            .tx
+            .fifotrig
+            .modify(|_, w| unsafe { w.txlvl().bits(6).txlvlena().enabled() });
+        // TX FIFO level interrupt enable
+        self.i2s.tx.fifointenset.write(|w| w.txlvl().enabled());
+
+        // enable interrupts
+        unsafe { pac::NVIC::unmask(pac::Interrupt::FLEXCOMM7) };
+
+        green_led().on();
+    }
+    /// Start audio recording. Clear the FIFO, enable interrupts, and enable the peripheral.
+    fn start_audio_in(&self) {
+        info!("recording starting, enabling interrupts");
+
+        self.i2s.rx.fifocfg.modify(|_, w| w.emptyrx().set_bit());
+        self.i2s.rx.fifointenclr.write(|w| w.rxlvl().set_bit());
+        // RX FIFO trigger threshold = >= 2 entries
+        self.i2s
+            .rx
+            .fifotrig
+            .modify(|_, w| unsafe { w.rxlvl().bits(1).rxlvlena().enabled() }); // 1 = generate when 2 pieces of data are in fifo
+        // RX FIFO level interrupt enable
+        self.i2s.rx.fifointenset.write(|w| w.rxlvl().enabled());
+        // Start the peripheral
+        self.i2s.rx.cfg1.modify(|_, w| w.mainenable().enabled());
+        unsafe { pac::NVIC::unmask(pac::Interrupt::FLEXCOMM6) };
+        red_led().on();
+    }
+    /// Stop audio playback. Disable interrupts, but leave the peripheral
+    /// running. It is responsible for clocks, so is needed to clock the CODEC
+    /// and input I2S. Leaving it running continuously is not harmful as the tx
+    /// FIFO will empty and then emit 0s to the DAC.
+    fn stop_audio_out(&self) {
+        pac::NVIC::mask(pac::Interrupt::FLEXCOMM7);
+        info!("playback stopped");
+        green_led().off();
+    }
+    /// Stop audio recording. Disable the peripheral and mask any interrupts.
+    fn stop_audio_in(&self) {
+        self.i2s.rx.cfg1.modify(|_, w| w.mainenable().disabled());
+        pac::NVIC::mask(pac::Interrupt::FLEXCOMM6);
+        info!("recording stopped");
+        red_led().off();
+    }
+}
+
+/// Implement a fixed internal clock offering a single fixed audio rate, which is always valid.
+impl<T: BbqHandle> ClockSource for Audio<T> {
    const CLOCK_TYPE: usbd_uac2::descriptors::ClockType = ClockType::InternalFixed;
    const SOF_SYNC: bool = false;
-    fn get_sample_rate(&self) -> core::result::Result<u32, usbd_uac2::UsbAudioClassError> {
-        Ok(Clock::RATES[0].min)
+    fn sample_rate(&self) -> u32 {
+        Self::RATES[0].min
    }
-    fn get_rates(
+    fn sample_rates(
        &self,
    ) -> core::result::Result<&[usbd_uac2::RangeEntry<u32>], usbd_uac2::UsbAudioClassError> {
-        Ok(&Clock::RATES)
+        Ok(&Self::RATES)
    }
-    fn get_clock_validity(&self) -> core::result::Result<bool, usbd_uac2::UsbAudioClassError> {
+    fn clock_validity(&self) -> core::result::Result<bool, usbd_uac2::UsbAudioClassError> {
        Ok(true)
    }
 }
-
-static FIFO_CONSUMER_STORE: StaticCell<Consumer<SampleType>> = StaticCell::new();
-static mut FIFO_CONSUMER: *mut Consumer<SampleType> = null_mut();
-
-#[interrupt]
-fn FLEXCOMM7() {
-    let i2s = unsafe { &*pac::I2S7::ptr() };
-
-    // refil the buffer to 4 frames / 8 samples
-    let fifo = unsafe { &mut *FIFO_CONSUMER };
-    while i2s.fifostat.read().txlvl().bits() <= 6 {
-        if let Some((l, r)) = fifo.dequeue() {
-            i2s.fifowr.write(|w| unsafe { w.bits(l as u32) });
-            i2s.fifowr.write(|w| unsafe { w.bits(r as u32) });
-        } else {
-            // Queue underflow
-            defmt::error!("queue underflow");
-            i2s.fifowr.write(|w| unsafe { w.bits(0) });
-            i2s.fifowr.write(|w| unsafe { w.bits(0) });
-        }
-    }
-}
-
-struct Audio<'a> {
-    running: AtomicBool,
-    i2s: I2sTx,
-    producer: Producer<'a, SampleType>,
-    integrator: AtomicI32,
-}
-impl<'a> Audio<'a> {
-    fn start(&self) {
-        self.running.store(true, Ordering::Relaxed);
-        defmt::info!("playback starting, enabling interrupts");
-        self.i2s.i2s.fifointenclr.write(|w| w.txlvl().set_bit());
-        // FIFO trigger threshold = <= 6 entries
-        self.i2s
-            .i2s
-            .fifotrig
-            .modify(|_, w| unsafe { w.txlvl().bits(6).txlvlena().enabled() });
-        // FIFO level interrupt enable
-        self.i2s.i2s.fifointenset.modify(|_, w| w.txlvl().enabled());
-        unsafe { pac::NVIC::unmask(pac::Interrupt::FLEXCOMM7) };
-    }
-    fn stop(&self) {
-        // If we don't disable interrupts while stopped, we will underflow constantly and continuously refill the fifo with 0s
-        // We could actually stop the I2S here, but sometimes that makes the DAC misbehave. The peripheral is configured to send
-        // 0s when the FIFO is empty, so this is fine.
-        self.running.store(true, Ordering::Relaxed);
-        defmt::info!("playback stopped");
-        pac::NVIC::mask(pac::Interrupt::FLEXCOMM7);
-    }
-}
-impl<'a, B: bus::UsbBus> UsbAudioClass<'a, B> for Audio<'_> {
-    fn alternate_setting_changed(&mut self, _terminal: usb_device::UsbDirection, alt_setting: u8) {
-        // alt setting 0 means stopped
-        match alt_setting {
-            0 => self.stop(),
-            1 => self.start(),
-            _ => defmt::error!("unexpected alt setting {}", alt_setting),
+/// Implement the main audio handlers. This is a very naive implementation that
+/// doesn't handle edge cases properly. For example, while altSetting=1
+/// indicates the host expects to be able to emit audio data to the endpoint, it
+/// does not indicate that the stream has started.
+impl<T: BbqHandle, B: bus::UsbBus> AudioHandler<'_, B> for Audio<T> {
+    /// On an alt setting change, start or stop the related audio pipeline. This
+    /// behaviour should be replaced by a state machine with at least an 'armed
+    /// but no data yet' state for playback.
+    fn alternate_setting_changed(&mut self, terminal: usb_device::UsbDirection, alt_setting: u8) {
+        match (terminal, alt_setting) {
+            (usb_device::UsbDirection::Out, 0) => self.stop_audio_out(),
+            (usb_device::UsbDirection::Out, 1) => self.start_audio_out(),
+            (usb_device::UsbDirection::In, 0) => self.stop_audio_in(),
+            (usb_device::UsbDirection::In, 1) => self.start_audio_in(),
+            _ => error!("unexpected alt setting {} on {}", alt_setting, terminal),
        }
    }
+    /// Receive audio data from USB. If we can, queue it into the output queue which will be drained by the ISR.
    fn audio_data_rx(
        &mut self,
-        ep: &usb_device::endpoint::Endpoint<'a, B, usb_device::endpoint::Out>,
+        ep: &usb_device::endpoint::Endpoint<'_, B, usb_device::endpoint::Out>,
    ) {
-        // Buffer must fit 1ms of audio data (based on how `usbd_uac2` sets up the descriptors), calculate that size here.
-        let mut buf = [0; SAMPLE_RATE as usize / 1000 * core::mem::size_of::<SampleType>()];
+        // Buffer must fit one microframe's (125us @ HS, 1ms @ FS) of audio data
+        // (based on how `usbd_uac2` sets up the descriptors), calculate that
+        // size here.
+        let mut buf = [0; (SAMPLE_RATE as usize / USB_FRAME_RATE + 1) * BYTES_PER_FRAME];
        let len = match ep.read(&mut buf) {
            Ok(len) => len,
            Err(_) => {
-                defmt::error!("usb error in rx callback");
+                error!("usb error in rx callback");
                return;
            }
        };
        let buf = &buf[..len];
-        // Translate the raw USB data into audio frames
-        for sample in buf
-            .chunks_exact(core::mem::size_of::<SampleType>())
-            .map(|b| {
-                // TODO: implement SampleType::from
-                (
-                    i32::from_le_bytes(b[..4].try_into().unwrap()),
-                    i32::from_le_bytes(b[4..].try_into().unwrap()),
-                )
-            })
-        {
-            if self.producer.enqueue(sample).is_err() {
-                defmt::error!("overflowed fifo, len: {}", self.producer.len());
+
+        if let Ok(mut wg) = self.producer.grant_exact(buf.len()) {
+            wg.copy_from_slice(buf);
+            wg.commit(buf.len());
+            PRODUCED_OUT.fetch_add(buf.len() as u32, Ordering::Relaxed);
+        } else {
+            blue_led().on();
+            error!("overflowed bbq, asked {}", buf.len());
        }
    }
+
+    /// Transmit audio data to USB. If we have data in the queue, write it to
+    /// the endpoint in appropriately sized microframes
+    fn audio_data_tx(
+        &mut self,
+        ep: &usb_device::endpoint::Endpoint<'_, B, usb_device::endpoint::In>,
+    ) {
+        const NOMINAL_SAMPLES: usize = SAMPLE_RATE as usize / USB_FRAME_RATE;
+        const DRAINING: i32 = ((FIFO_LENGTH * 4) / 10) as i32;
+        const FILLING: i32 = ((FIFO_LENGTH * 6) / 10) as i32;
+
+        // Allocate space for one additional audio frame, in case the host is
+        // running slower than us and we need to occasionally stuff an extra
+        // frame.
+        let mut buf = [0; (NOMINAL_SAMPLES + 1) * BYTES_PER_FRAME];
+
+        let fill = PRODUCED_IN
+            .load(Ordering::Acquire)
+            .wrapping_sub(CONSUMED_IN.load(Ordering::Acquire)) as i32
+            / BYTES_PER_FRAME as i32;
+
+        // Decide how many samples to write based on fill, this is how we deal with clock slippage.
+        //  Draining (<40%) -> 1 fewer
+        //  Filling (>50%) -> 1 more
+        //  Nominal -> Nominal
+        let samples = match fill {
+            f if f < DRAINING => NOMINAL_SAMPLES - 1,
+            f if f > FILLING => NOMINAL_SAMPLES + 1,
+            _ => NOMINAL_SAMPLES,
+        };
+        let mut written = 0;
+        let mut woff = 0usize;
+
+        while written < samples {
+            let Ok(rgr) = self.consumer.read() else {
+                // warn!("underflowed IN queue, wrote {} of {}", written, samples);
+                break;
+            };
+
+            let available_frames = rgr.len() / BYTES_PER_FRAME;
+
+            if available_frames == 0 {
+                break;
+            }
+
+            let to_copy = (samples - written).min(available_frames);
+            let bytes = to_copy * BYTES_PER_FRAME;
+
+            buf[woff..woff + bytes].copy_from_slice(&rgr[..bytes]);
+
+            woff += bytes;
+            rgr.release(bytes);
+            written += to_copy;
+            CONSUMED_IN.fetch_add(to_copy as u32, Ordering::Relaxed);
+        }
+
+        if let Err(e) = ep.write(&buf[..written * BYTES_PER_FRAME]) {
+            warn!("Error writing to IN EP: {:?}", e);
+        }
    }

    /// Provide rate feedback to the host, so that it doesn't over- or underflow
-    /// our queue.
-    fn feedback(&mut self) -> Option<UsbIsochronousFeedback> {
-        // Samples per USB interval (1ms)
-        const FRAME_SAMPLES: i32 = SAMPLE_RATE as i32 / 1000;
+    /// our queue. This implementation is not tuned and without an I term is
+    /// pretty unstable, but works fine.
+    fn feedback(&mut self, nominal_rate: UsbIsochronousFeedback) -> Option<UsbIsochronousFeedback> {
+        let target = FIFO_LENGTH as i32 / 2;

-        // Keep FIFO around half full, minus one USB packet worth
-        const TARGET: i32 = FIFO_LENGTH as i32 / 2 - FRAME_SAMPLES;
+        let fill = PRODUCED_OUT
+            .load(Ordering::Acquire)
+            .wrapping_sub(CONSUMED_OUT.load(Ordering::Acquire)) as i32
+            / BYTES_PER_FRAME as i32;

-        // 16.16 fixed-point nominal feedback value
-        const NOMINAL: i32 = FRAME_SAMPLES << 16;
-        const MAX_ERROR: i32 = FRAME_SAMPLES / 2;
+        let error = fill - target;
+        // Clamp excursions.
+        let (i, _f) = nominal_rate.parts();
+        let error = error.clamp(-(i as i32 * 4), i as i32 * 4);

-        let queuelen = self.producer.len() as i32;
+        let p = error << 8;

-        let error = (queuelen - TARGET).clamp(-MAX_ERROR, MAX_ERROR);
+        let correction = -p;
+        let nominal_v = nominal_rate.to_u32_12_13() as i32;

-        // slow down accumulation of I
-        const I_ACCUM_DIV: i32 = 8;
-        let i_delta = error / I_ACCUM_DIV;
-        let integrator = self.integrator.fetch_add(i_delta, Ordering::Relaxed) + i_delta;
+        let mut v = nominal_v + correction;

-        // Integrator saturates at 1024xFRAME_SAMPLES
-        let i_limit = FRAME_SAMPLES << 10;
-        let integrator = integrator.clamp(-i_limit, i_limit);
+        // Clamp corrections
+        v = v.clamp(nominal_v - (1 << 14), nominal_v + (1 << 14));

-        // Gains
-        let p = error << 7;
-        let i = integrator << 3;
-
-        // Total correction in 16.16 space
-        let correction = -(p + i);
-
-        let v = NOMINAL + correction;
-
-        defmt::debug!(
-            "q:{} err:{} i:{} fb:{}",
-            queuelen,
-            error,
-            integrator,
-            v >> 16
-        );
+        // Note: this log will cause continuous underflows
+        debug!("fill:{} err:{} fb:{=u32:x}", fill, error, v as u32);

        Some(UsbIsochronousFeedback::new(v as u32))
    }
@@ -227,10 +407,7 @@ fn main() -> ! {

    debug!("start");

-    let mut red_led = pins::Pio1_6::take()
-        .unwrap()
-        .into_gpio_pin(&mut iocon, &mut gpio)
-        .into_output_low(); // start turned off
+    hw::init_leds(&mut iocon, &mut gpio);

    debug!("iocon");
    let usb0_vbus_pin = pins::Pio0_22::take()
@@ -240,16 +417,16 @@ fn main() -> ! {
        pins::Pio1_20::take().unwrap().into_i2c4_scl_pin(&mut iocon),
        pins::Pio1_21::take().unwrap().into_i2c4_sda_pin(&mut iocon),
    );
-    // We can initialize and iocon these, but there is no peripheral, so they do not get used
+    // We can initialize and iocon these, but there is no peripheral driver, so the variables do not get used
    let _codec_i2s_pins = (
        pins::Pio0_21::take().unwrap().into_spi7_sck_pin(&mut iocon),
        pins::Pio0_20::take().unwrap().into_i2s7_sda_pin(&mut iocon),
        pins::Pio0_19::take().unwrap().into_i2s7_ws_pin(&mut iocon),
+        pins::Pio1_13::take().unwrap().into_i2s6_sda_pin(&mut iocon),
        pins::Pio1_31::take().unwrap(), // MCLK
    );

    debug!("clocks");
-    // Run the system clock at 96MHz. The lpc55-hal will run it from the FRO.
    let clocks = hal::ClockRequirements::default()
        .system_frequency(96.MHz())
        .configure(&mut anactrl, &mut pmc, &mut syscon)
@@ -275,84 +452,63 @@ fn main() -> ! {
    );

    let i2s_peripheral = {
+        let fc6 = hal.flexcomm.6.release();
        let fc7 = hal.flexcomm.7.release();
-        hw::init_i2s(fc7.0, fc7.2, &mut syscon)
+
+        hw::init_i2s(fc7.0, fc7.2, fc6.0, fc6.2, &mut syscon)
    };

+    debug!("usb");
    #[cfg(feature = "usbhs")]
-    let usb_peripheral = hal.usbhs.enabled_as_device(
+    let (usb_speed, usb_peripheral) = (
+        UsbSpeed::High,
+        hal.usbhs.enabled_as_device(
            &mut anactrl,
            &mut pmc,
            &mut syscon,
            &mut _delay_timer,
            clocks.support_usbhs_token().unwrap(),
+        ),
    );
    #[cfg(feature = "usbfs")]
-    let usb_peripheral = hal.usbfs.enabled_as_device(
+    let (usb_speed, usb_peripheral) = (
+        UsbSpeed::Full,
+        hal.usbfs.enabled_as_device(
            &mut anactrl,
            &mut pmc,
            &mut syscon,
            clocks.support_usbfs_token().unwrap(),
+        ),
    );
-
    let usb_bus = UsbBus::new(usb_peripheral, usb0_vbus_pin);

-    defmt::debug!("codec init");
+    debug!("codec init");
    wm8904::init_codec(&mut i2c_bus);
-    let queue = cortex_m::singleton!(
-        : Queue<SampleType, FIFO_LENGTH>
-        = Queue::new()
-    )
-    .unwrap();
-    let (producer, consumer) = queue.split();

-    let consumer_ref = FIFO_CONSUMER_STORE.init(consumer);
-    unsafe { FIFO_CONSUMER = consumer_ref as *mut _ };
-
-    let mut clock = Clock {};
    let mut audio = Audio {
        i2s: i2s_peripheral,
-        producer,
-        running: AtomicBool::new(false),
-        integrator: AtomicI32::new(0),
+        producer: QUEUE_AUDIO_OUT.stream_producer(),
+        consumer: QUEUE_AUDIO_IN.stream_consumer(),
    };

-    let config = AudioClassConfig::new(UsbSpeed::High, FunctionCode::Other, &mut clock, &mut audio)
-        .with_output_config(TerminalConfig::new(
-            4,
-            1,
-            2,
-            FormatType1 {
-                bit_resolution: 32,
-                bytes_per_sample: 4,
-            },
-            TerminalType::ExtLineConnector,
-            ChannelConfig::default_chans(2),
-            IsochronousSynchronizationType::Asynchronous,
-            LockDelay::Milliseconds(10),
-            None,
-        ));
+    let config = UsbAudioClassConfig::new(usb_speed, FunctionCode::IoBox, &mut audio)
+        .with_output_config(TerminalConfig::builder().base_id(2).build())
+        .with_input_config(TerminalConfig::builder().base_id(4).build());

    let mut uac2 = config.build(&usb_bus).unwrap();

-    let mut usb_dev = UsbDeviceBuilder::new(&usb_bus, UsbVidPid(0x1209, 0xcc1d))
-        .composite_with_iads()
+    let mut usb_dev = usbd_uac2::builder(&usb_bus, UsbVidPid(USB_VID, USB_PID))
        .strings(&[StringDescriptors::default()
-            .manufacturer("Generic")
-            .product("usbd_uac2 device")
-            .serial_number("123456789")])
+            .manufacturer(USB_MANUFACTURER)
+            .product(USB_PRODUCT)])
        .unwrap()
-        .max_packet_size_0(64)
+        .max_packet_size_0(64) // Required to be 64 on HS, allowed on FS
        .unwrap()
-        .device_class(0xef)
-        .device_sub_class(0x02)
-        .device_protocol(0x01)
        .build();

-    defmt::info!("main loop");
+    debug!("main loop");

    loop {
        usb_dev.poll(&mut [&mut uac2]);
-        red_led.set_high().ok(); // Turn off
    }
 }
@@ -1,7 +1,7 @@
 use cortex_m::prelude::{_embedded_hal_blocking_i2c_Write, _embedded_hal_blocking_i2c_WriteRead};
 use defmt::warn;

-use crate::{CODEC_I2C_ADDR, MCLK_FREQ, SAMPLE_RATE, SampleType};
+use crate::{BYTES_PER_FRAME, CODEC_I2C_ADDR, MCLK_FREQ, SAMPLE_RATE};

 // copied from NXP SDK WM8904_Init
 pub(crate) fn init_codec<T>(i2c: &mut T)
@@ -31,26 +31,29 @@ where
    }
    defmt::debug!("[codec] write seq done");
    i2c.write(CODEC_I2C_ADDR, &[0x14, 0x00, 0x00]).ok(); // clock rates 0
-    i2c.write(CODEC_I2C_ADDR, &[0x0c, 0x00, 0x00]).ok(); // power management 0 = IN PGAs disabled
+    i2c.write(CODEC_I2C_ADDR, &[0x05, 0x00, 0x03]).ok(); // vmid control 0 = normal | enabled
+    i2c.write(CODEC_I2C_ADDR, &[0x0c, 0x00, 0x03]).ok(); // power management 0 = INL_ENA | INR_ENA
    i2c.write(CODEC_I2C_ADDR, &[0x0e, 0x00, 0x03]).ok(); // power management 2 = HPL_PGA_ENA | HPR_PGA_ENA
    i2c.write(CODEC_I2C_ADDR, &[0x0f, 0x00, 0x00]).ok(); // power management 3 = line outs disabled

-    i2c.write(CODEC_I2C_ADDR, &[0x12, 0x00, 0x0c]).ok(); // power management 6 = DACL_ENA | DACR_ENA
-    i2c.write(CODEC_I2C_ADDR, &[0x0a, 0x00, 0x00]).ok(); // analog adc 0 = ADC_OSR128
+    i2c.write(CODEC_I2C_ADDR, &[0x12, 0x00, 0x0f]).ok(); // power management 6 = DACL_ENA | DACR_ENA | ADCL_ENA | ADCR_ENA
+    i2c.write(CODEC_I2C_ADDR, &[0x0a, 0x00, 0x01]).ok(); // analog adc 0 = ADC_OSR128
    i2c.write(CODEC_I2C_ADDR, &[0x18, 0x00, 0x50]).ok(); // audio if 0 = AIFADCR_SRC | AIFDACR_SRC
    i2c.write(CODEC_I2C_ADDR, &[0x21, 0x00, 0x40]).ok(); // dac digital 1 = DAC_OSR128
    i2c.write(CODEC_I2C_ADDR, &[0x2c, 0x00, 0x05]).ok(); // analog lin 0 = 0dB (unmute)
    i2c.write(CODEC_I2C_ADDR, &[0x2d, 0x00, 0x05]).ok(); // analog rin 0 = 0dB (unmute)
+    i2c.write(CODEC_I2C_ADDR, &[0x2e, 0x00, 1 << 4]).ok(); // analog lin 1 = single ended, inv_input = in2l
+    i2c.write(CODEC_I2C_ADDR, &[0x2f, 0x00, 1 << 4]).ok(); // analog rin 1 = single ended, inv_input = in2r
    i2c.write(CODEC_I2C_ADDR, &[0x39, 0x00, 0x39]).ok(); // analog out1 left = vol=0dB
    i2c.write(CODEC_I2C_ADDR, &[0x3a, 0x00, 0x39]).ok(); // analog out1 right = vol=0dB
    i2c.write(CODEC_I2C_ADDR, &[0x3b, 0x00, 0x39]).ok(); // analog out2 left = vol=0dB
    i2c.write(CODEC_I2C_ADDR, &[0x3c, 0x00, 0x39]).ok(); // analog out2 right = vol=0dB
-    i2c.write(CODEC_I2C_ADDR, &[0x43, 0x00, 0x03]).ok(); // dc server 0 = HPOUTL_ENA | HPOUTR_ENA
+    i2c.write(CODEC_I2C_ADDR, &[0x43, 0x00, 0x03]).ok(); // dc servo 0 = HPOUTL_ENA | HPOUTR_ENA
    i2c.write(CODEC_I2C_ADDR, &[0x5a, 0x00, 0xff]).ok(); // analog hp 0 = remove all shorts etc
    i2c.write(CODEC_I2C_ADDR, &[0x5e, 0x00, 0xff]).ok(); // analog lineout 0 = remove all shorts etc
    i2c.write(CODEC_I2C_ADDR, &[0x68, 0x00, 0x01]).ok(); // enable class w charge pump
    i2c.write(CODEC_I2C_ADDR, &[0x62, 0x00, 0x01]).ok(); // enable charge pump
-    let aif_wl = match core::mem::size_of::<SampleType>() {
+    let aif_wl = match BYTES_PER_FRAME {
        4 => 0, // 16 bits per sample
        8 => 3, // 32 bits per sample
        _ => {
@@ -98,7 +101,7 @@ where
    i2c.write(CODEC_I2C_ADDR, &[0x16, 0x00, 0x0f]).ok(); // clock rates 2 = CLK_SYS_ENA

    // Calculate bclk_div
-    let bits_per_frame = core::mem::size_of::<SampleType>() * 8;
+    let bits_per_frame = BYTES_PER_FRAME * 8;
    let bits_per_second = bits_per_frame as u32 * SAMPLE_RATE;
    let bclk_div = MCLK_FREQ / bits_per_second;
    i2c.write(CODEC_I2C_ADDR, &[0x1a, 0x00, bclk_div as u8])
@@ -106,5 +109,8 @@ where

    i2c.write(CODEC_I2C_ADDR, &[0x1b, 0x00, 0x00]).ok(); // audio interface 3 = input lrclock
    i2c.write(CODEC_I2C_ADDR, &[0x3d, 0x00, 0x00]).ok(); // analog out12 zc = play source = dac
-    i2c.write(CODEC_I2C_ADDR, &[0x1e, 0x01, 0xff]).ok(); // dac vol left = update left/right = 0dB
+    i2c.write(CODEC_I2C_ADDR, &[0x1e, 0x01, 0xc0]).ok(); // dac vol left = update left/right = 0dB
+    i2c.write(CODEC_I2C_ADDR, &[0x24, 0x01, 0xc0]).ok(); // adc vol left = update left/right = 0dB
+    i2c.write(CODEC_I2C_ADDR, &[0x2c, 0x00, 0x05]).ok(); // pga gain = 0dB
+    i2c.write(CODEC_I2C_ADDR, &[0x2d, 0x00, 0x05]).ok(); // pga gain = 0dB
 }
@@ -195,7 +195,7 @@ impl Descriptor for ClockSource {
        writer.write_u8(self.bm_attributes())?; // bmAttributes
        writer.write_u8(self.bm_controls())?; // bmControls
        writer.write_u8(self.assoc_terminal)?; // bAssocTerminal
-        writer.write_u8(self.string.map_or(0, |n| u8::from(n)))?; // iClockSource
+        writer.write_u8(self.string.map_or(0, u8::from))?; // iClockSource
        Ok(())
    }
 }
@@ -247,7 +247,7 @@ impl Descriptor for InputTerminal {
                | ((self.overflow_control as u8) << 2)
                | ((self.phantom_power_control as u8) << 4),
        )?;
-        writer.write_u8(self.string.map_or(0, |s| u8::from(s)))?;
+        writer.write_u8(self.string.map_or(0, u8::from))?;
        Ok(())
    }
 }
@@ -289,7 +289,7 @@ impl Descriptor for OutputTerminal {
                | ((self.underflow_control as u8) << 6),
        )?;
        writer.write_u8(self.overflow_control as u8)?;
-        writer.write_u8(self.string.map_or(0, |n| u8::from(n)))?; // iTerminal
+        writer.write_u8(self.string.map_or(0, u8::from))?; // iTerminal
        Ok(())
    }
 }
@@ -839,7 +839,7 @@ impl Descriptor for AudioStreamingInterface {
        writer.write_u32::<LittleEndian>(self.format_bitmap as u32)?;
        writer.write_u8(self.num_channels)?;
        writer.write(&self.channel_config.bytes)?;
-        writer.write_u8(self.string.map_or(0, |s| u8::from(s)))?;
+        writer.write_u8(self.string.map_or(0, u8::from))?;
        Ok(())
    }
 }
@@ -1,3 +1,47 @@
+//! USB Audio Class 2.0
+//!
+//! This crate provides a USB Audio Class 2.0 implementation for
+//! [usb-device](https://crates.io/crates/usb-device). It implements all
+//! required elements of the specification, however many controls are not
+//! implemented (e.g. mixers, effects).
+//!
+//! Device behaviour is driven by implementing the `ClockSource` and
+//! `AudioHandler` traits to configure the audio pipeline and source/sink data
+//! to/from USB.
+//!
+//! Example (creates a UAC2 device with in and out streams):
+//!
+//! ```ignore
+//! let mut audio = YourTraitImpl {...};
+//!
+//! let config = UsbAudioClassConfig::new(usb_speed, FunctionCode::IoBox, &mut audio)
+//!     // base_id is USB entity ID, id 1 is always taken by the clock source, and each stream builds 2 entities
+//!     .with_output_config(TerminalConfig::builder().base_id(2).build())
+//!     .with_input_config(TerminalConfig::builder().base_id(4).build());
+//!
+//! let mut uac2 = config.build(&usb_bus).unwrap();
+//!
+//! let mut usb_dev = usbd_uac2::builder(&usb_bus, UsbVidPid(0x1209, 0x0001))
+//!     .strings(&[StringDescriptors::default()
+//!         .manufacturer("usbd_uac2")
+//!         .product("example")])
+//!     .unwrap()
+//!     .max_packet_size_0(64) // Required to be 64 on HS
+//!     .unwrap()
+//!     .build();
+//! ```
+//!
+//! No work needs to be done in the poll loop, the class implementation will
+//! call your trait callbacks as required, just call the usb poll as usual:
+//!
+//! ```ignore
+//! loop {
+//!     usb_dev.poll(&mut [&mut uac2]);
+//! }
+//! ```
+//!
+//! See the trait documentation or examples for additional details.
+
 #![no_std]
 #![allow(dead_code)]

@@ -8,24 +52,19 @@ mod log;

 use core::cmp::Ordering;
 use core::marker::PhantomData;
-use core::sync::atomic::AtomicUsize;

-use byteorder_embedded_io::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use constants::*;
 use descriptors::*;
+#[allow(unused_imports)]
 use log::*;

+use byteorder_embedded_io::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use num_traits::{ConstZero, ToPrimitive};
 use usb_device::control::{Recipient, Request, RequestType};
-use usb_device::device::DEFAULT_ALTERNATE_SETTING;
+use usb_device::device::{DEFAULT_ALTERNATE_SETTING, UsbDeviceBuilder, UsbVidPid};
 use usb_device::endpoint::{self, Endpoint, EndpointDirection, In, Out};
 use usb_device::{UsbDirection, class_prelude::*};

-pub use constants::USB_CLASS_AUDIO;
-
-#[cfg(feature = "defmt")]
-use defmt;
-
 mod sealed {
    pub trait Sealed {}
 }
@@ -66,7 +105,10 @@ impl RangeType for u8 {}
 impl RangeType for u16 {}
 impl RangeType for u32 {}

-#[derive(PartialEq, Eq, Ord)]
+/// Represent a range request/response.
+///
+/// ref: UAC2 5.2.2
+#[derive(PartialEq, Eq)]
 pub struct RangeEntry<T: RangeType> {
    pub min: T,
    pub max: T,
@@ -85,10 +127,7 @@ impl<T: RangeType> RangeEntry<T> {
        }
    }

-    pub fn write<W: embedded_io::Write>(
-        &self,
-        mut buf: W,
-    ) -> core::result::Result<usize, W::Error> {
+    fn write<W: embedded_io::Write>(&self, mut buf: W) -> core::result::Result<usize, W::Error> {
        buf.write_all(self.min.to_le_bytes().as_ref())?;
        buf.write_all(self.max.to_le_bytes().as_ref())?;
        buf.write_all(self.res.to_le_bytes().as_ref())?;
@@ -96,52 +135,46 @@ impl<T: RangeType> RangeEntry<T> {
    }
 }

-/// The spec guarantees that ranges do not overlap, so compare by min is correct.
+// The spec guarantees that ranges do not overlap, so compare by min is correct.
 impl<T: RangeType + PartialOrd> PartialOrd for RangeEntry<T> {
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        self.min.partial_cmp(&other.min)
+        Some(self.cmp(other))
    }
 }
-
-/// Fixed point 10.14, packed to the least significant 3-bytes of a 4-byte USB feedback endpoint response
+impl<T: RangeType + PartialOrd> Ord for RangeEntry<T> {
+    fn cmp(&self, other: &Self) -> Ordering {
+        self.min.cmp(&other.min)
+    }
+}
+/// Represent Isochronous feedback as integer and fractional parts, internally as 16.16.
+///
+/// Provides conversions to and from the different USB formats.
 #[derive(Copy, Clone)]
-pub struct UsbIsochronousFeedback {
-    pub int: u16,
-    pub frac: u16,
-}
+pub struct UsbIsochronousFeedback(u32);

 impl UsbIsochronousFeedback {
+    pub fn new(v: u32) -> Self {
+        Self(v)
+    }
    /// Accepts all u16 values, saturating the output depending on format
    pub fn new_frac(int: u16, frac: u16) -> Self {
-        Self { int, frac }
+        Self(((int as u32) << 16) | frac as u32)
    }
+    /// Convert float to fixed point
    pub fn new_float(rate: f32) -> Self {
        let fb = (rate * 65536.0 + 0.5) as u32;
-        Self::new(fb)
-    }
-    /// Assumed 16.16, not either of the USB formats
-    pub fn new(value: u32) -> Self {
-        Self {
-            int: (value >> 16) as u16,
-            frac: (value & 0xffff) as u16,
+        Self(fb)
    }
+    pub fn parts(&self) -> (u16, u16) {
+        ((self.0 >> 16) as u16, (self.0 & 0xffff) as u16)
    }
    /// Serialize into a u32 in 16.16 representation for USB HS
    pub fn to_u32_12_13(&self) -> u32 {
-        let int = (self.int as u32) << 16;
-        // ostensibly 13 bits, so should require << 3, but USB allows us to use
-        // these bits for 'extra precision'. So we may as well just treat it as
-        // 16.16. The application can << 3 if it wants to for some reason.
-        let frac = (self.frac as u32) & 0xffff;
-
-        int | frac
+        self.0
    }
-    /// Serialize into a u32 in 10.14 representation for USB FS (take the 3 LSB)
+    /// Serialize into a u32 in 10.14 representation for USB FS
    pub fn to_u32_10_14(&self) -> u32 {
-        let int = (self.int as u32) << 14;
-        let frac = (self.frac as u32) & 0x3fff;
-
-        int | frac
+        (self.0 + 2) >> 2
    }
    /// Serialize into 16.16 little endian byte array for USB HS
    pub fn to_bytes_12_13(&self) -> [u8; 4] {
@@ -156,16 +189,15 @@ impl UsbIsochronousFeedback {

 /// A trait for implementing USB Audio Class 2 devices
 ///
-/// Contains callback methods which will be called by the class driver. All
-/// callbacks are optional, which may be useful for a tight-loop polling implementation
-/// but most implementations will want to implement at least `audio_data_rx`.
-///
-/// Unimplemented callbacks should return `Ok(())` if a result is required.
-
-pub trait UsbAudioClass<'a, B: UsbBus> {
+/// Contains callback methods which will be called by the class driver.
+pub trait AudioHandler<'a, B: UsbBus> {
    /// Called when audio data is received from the host. `ep` is ready for
    /// `ep.read()`.
-    fn audio_data_rx(&mut self, ep: &Endpoint<'a, B, endpoint::Out>) {}
+    fn audio_data_rx(&mut self, ep: &Endpoint<'a, B, endpoint::Out>);
+
+    /// Called when we must produce audio data for the host. `ep` is ready for
+    /// `ep.write()`.
+    fn audio_data_tx(&mut self, ep: &Endpoint<'a, B, endpoint::In>);

    /// Called when it's time to send an isochronous feedback update. Should
    /// return the correct feedback payload. Feedback always runs at 1ms (in
@@ -173,14 +205,15 @@ pub trait UsbAudioClass<'a, B: UsbBus> {
    ///
    /// Required for isochronous asynchronous mode to work properly. If None is
    /// returned, no IN packet will be emitted at feedback time.
-    fn feedback(&mut self, nominal_rate: UsbIsochronousFeedback) -> Option<UsbIsochronousFeedback> {
-        None
-    }
+    fn feedback(&mut self, nominal: UsbIsochronousFeedback) -> Option<UsbIsochronousFeedback>;

    /// Called when the alternate setting of `terminal`'s interface is changed,
-    /// before the `AudioStream` is updated. Currently not very useful since we
-    /// don't implement alternate settings.
-    fn alternate_setting_changed(&mut self, terminal: UsbDirection, alt_setting: u8) {}
+    /// before the `AudioStream` is updated. This is how the host signals start/stop
+    /// of audio streaming. We do not expect audio frames when alt setting is 0.
+    ///
+    /// The implementation will also call `alternate_setting_changed(_, 0)` when
+    /// the host disconnects / resets.
+    fn alternate_setting_changed(&mut self, terminal: UsbDirection, alt_setting: u8);
 }

 /// A trait for implementing Sampling Frequency Control for USB Audio Clock Sources
@@ -191,7 +224,7 @@ pub trait UsbAudioClass<'a, B: UsbBus> {
 /// Unimplemented callbacks should return `Err(UsbAudioClassError::NotImplemented)`. Other
 /// errors will panic (the underlying callbacks are not fallible). If you need to handle errors,
 /// you should use the callback to infalliably signal another task.
-pub trait UsbAudioClockImpl {
+pub trait ClockSource {
    const CLOCK_TYPE: ClockType;
    const SOF_SYNC: bool;
    /// Called when the host or class needs the current sample rate. Returns the
@@ -200,9 +233,10 @@ pub trait UsbAudioClockImpl {
    ///
    /// Should never return 0 as it may be used in divides in the feedback loop
    /// and that would cause a hard fault.
-    fn get_sample_rate(&self) -> u32;
+    fn sample_rate(&self) -> u32;
    /// Called when the host requests to set the sample rate. Not necessarily called at all startups,
    /// so alt_setting should start/stop the clock. Not required for 'fixed' clocks.
+    #[allow(unused_variables)]
    fn set_sample_rate(
        &mut self,
        sample_rate: u32,
@@ -211,14 +245,14 @@ pub trait UsbAudioClockImpl {
    }
    /// Called when the host requests to get the clock validity. Returns `true`
    /// if the clock is stable and on frequency.
-    fn get_clock_validity(&self) -> core::result::Result<bool, UsbAudioClassError> {
+    fn clock_validity(&self) -> core::result::Result<bool, UsbAudioClassError> {
        Err(UsbAudioClassError::NotImplemented)
    }
    /// Called during descriptor construction to describe if the clock validity can be read (write is not valid).
    ///
    /// By default will call `get_clock_validity` to determine if the clock validity can be read.
-    fn get_validity_access(&self) -> core::result::Result<bool, UsbAudioClassError> {
-        match self.get_clock_validity() {
+    fn clock_validity_access(&self) -> core::result::Result<bool, UsbAudioClassError> {
+        match self.clock_validity() {
            Ok(_) => Ok(true),
            Err(UsbAudioClassError::NotImplemented) => Ok(false),
            Err(err) => Err(err),
@@ -236,36 +270,30 @@ pub trait UsbAudioClockImpl {
    ///     its MIN and MAX subattribute and the RES subattribute must be set to zero
    ///
    /// ref: USB Audio Class Specification 2.0 5.2.1 & 5.2.3.3
-    fn get_rates(&self) -> core::result::Result<&[RangeEntry<u32>], UsbAudioClassError>;
+    fn sample_rates(&self) -> core::result::Result<&[RangeEntry<u32>], UsbAudioClassError>;

-    /// Called when the audio device's AltSetting is changed. Usually 0 signals shutdown of the
-    /// streaming audio and 1 signals start of streaming. This should be used to start the clock
-    /// (and stop it if desired). If unimplemented, does nothing - keep the clock running at all times.
-    fn alt_setting(&mut self, alt_setting: u8) -> core::result::Result<(), UsbAudioClassError> {
-        Ok(())
-    }
-
-    /// Build the ClockSource descriptor. It is not intended to override this method.
+    /// Build the ClockSource descriptor. It is not intended to override this
+    /// method, but provided so you can.
    ///
    /// Assumes access control based on clock type. Internal fixed/variable are read only,
    /// external and internal programmable are programmable.
-    fn get_configuration_descriptor(
+    fn clock_configuration_descriptor(
        &self,
        id: u8,
        string: Option<StringIndex>,
-    ) -> usb_device::Result<ClockSource> {
+    ) -> usb_device::Result<descriptors::ClockSource> {
        let frequency_access = match Self::CLOCK_TYPE {
            ClockType::InternalFixed | ClockType::InternalVariable => AccessControl::ReadOnly,
            ClockType::External | ClockType::InternalProgrammable => AccessControl::Programmable,
        };
-        let validity_access = match self.get_validity_access() {
+        let validity_access = match self.clock_validity_access() {
            Ok(true) => AccessControl::ReadOnly,
            Ok(false) | Err(UsbAudioClassError::NotImplemented) => AccessControl::NotPresent,
            _ => return Err(UsbError::Unsupported),
        };

-        let cs = ClockSource {
-            id: id,
+        let cs = descriptors::ClockSource {
+            id,
            clock_type: Self::CLOCK_TYPE,
            sof_sync: Self::SOF_SYNC,
            frequency_access,
@@ -282,6 +310,102 @@ trait TerminalConfigurationDescriptors {
    fn get_configuration_descriptors(&self) -> (InputTerminal, OutputTerminal);
 }

+pub struct TerminalConfigBuilder<D: EndpointDirection> {
+    base_id: Option<u8>,
+    clock_source_id: Option<u8>,
+    num_channels: Option<u8>,
+    format: Option<FormatType1>,
+    terminal_type: Option<TerminalType>,
+    channel_config: Option<ChannelConfig>,
+    sync_type: Option<IsochronousSynchronizationType>,
+    lock_delay: Option<LockDelay>,
+    string: Option<StringIndex>,
+    _direction: PhantomData<D>,
+}
+
+// Global builder initialization defaults
+impl<D: EndpointDirection> TerminalConfigBuilder<D> {
+    fn new() -> Self {
+        Self {
+            base_id: None,
+            clock_source_id: None,
+            num_channels: None,
+            format: None,
+            terminal_type: None,
+            channel_config: None,
+            sync_type: None,
+            lock_delay: None,
+            string: None,
+            _direction: PhantomData,
+        }
+    }
+
+    pub fn base_id(mut self, id: u8) -> Self {
+        self.base_id = Some(id);
+        self
+    }
+
+    pub fn clock_source_id(mut self, id: u8) -> Self {
+        self.clock_source_id = Some(id);
+        self
+    }
+
+    pub fn num_channels(mut self, channels: u8) -> Self {
+        self.num_channels = Some(channels);
+        self
+    }
+
+    pub fn format(mut self, format: FormatType1) -> Self {
+        self.format = Some(format);
+        self
+    }
+
+    pub fn terminal_type(mut self, t: TerminalType) -> Self {
+        self.terminal_type = Some(t);
+        self
+    }
+
+    pub fn channel_config(mut self, config: ChannelConfig) -> Self {
+        self.channel_config = Some(config);
+        self
+    }
+
+    pub fn sync_type(mut self, sync: IsochronousSynchronizationType) -> Self {
+        self.sync_type = Some(sync);
+        self
+    }
+
+    pub fn lock_delay(mut self, delay: LockDelay) -> Self {
+        self.lock_delay = Some(delay);
+        self
+    }
+
+    pub fn string(mut self, index: StringIndex) -> Self {
+        self.string = Some(index);
+        self
+    }
+
+    pub fn build(self) -> TerminalConfig<D> {
+        TerminalConfig {
+            base_id: self.base_id.expect("base_id is required"),
+            clock_source_id: self.clock_source_id.unwrap_or(1),
+            num_channels: self.num_channels.unwrap_or(2),
+            format: self.format.unwrap_or(FormatType1 {
+                bytes_per_sample: 4,
+                bit_resolution: 32,
+            }),
+            terminal_type: self.terminal_type.unwrap_or(TerminalType::ExtUndefined),
+            channel_config: self
+                .channel_config
+                .unwrap_or(ChannelConfig::default_chans(self.num_channels.unwrap_or(2))),
+            sync_type: IsochronousSynchronizationType::Asynchronous,
+            lock_delay: LockDelay::Undefined(0),
+            string: self.string, // Implicitly handles None or Option mapping
+            _direction: PhantomData,
+        }
+    }
+}
+
 pub struct TerminalConfig<D: EndpointDirection> {
    /// USB terminal in the D direction will have this id, audio terminal will have this id + 1
    base_id: u8,
@@ -296,9 +420,9 @@ pub struct TerminalConfig<D: EndpointDirection> {
    _direction: PhantomData<D>,
 }

-// TODO: builder pattern
 impl<D: EndpointDirection> TerminalConfig<D> {
-    pub fn new(
+    #[allow(clippy::too_many_arguments)]
+    fn new(
        base_id: u8,
        clock_source_id: u8,
        num_channels: u8,
@@ -326,8 +450,12 @@ impl<D: EndpointDirection> TerminalConfig<D> {
    pub fn bytes_per_frame(&self) -> u32 {
        self.format.bytes_per_sample as u32 * self.num_channels as u32
    }
+
+    pub fn builder() -> TerminalConfigBuilder<D> {
+        TerminalConfigBuilder::new()
    }
-impl<'a> TerminalConfigurationDescriptors for TerminalConfig<Out> {
+}
+impl TerminalConfigurationDescriptors for TerminalConfig<Out> {
    fn get_configuration_descriptors(&self) -> (InputTerminal, OutputTerminal) {
        let input_terminal = InputTerminal {
            id: self.base_id,
@@ -364,7 +492,7 @@ impl<'a> TerminalConfigurationDescriptors for TerminalConfig<Out> {
    // fn get_interface_descriptor(&self, id: InterfaceIndex) )
 }

-impl<'a> TerminalConfigurationDescriptors for TerminalConfig<In> {
+impl TerminalConfigurationDescriptors for TerminalConfig<In> {
    fn get_configuration_descriptors(&self) -> (InputTerminal, OutputTerminal) {
        let output_terminal = OutputTerminal {
            id: self.base_id,
@@ -426,10 +554,9 @@ pub enum UsbSpeed {
 /// A single Clock Source is always required, but a fully custom descriptor set can be built by only providing
 /// the Clock Source and additional descriptors, if the Terminal descriptors are inappropriate.
 ///
-pub struct AudioClassConfig<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> {
+pub struct UsbAudioClassConfig<'a, B: UsbBus, AU: AudioHandler<'a, B> + ClockSource> {
    pub speed: UsbSpeed,
    pub device_category: FunctionCode,
-    pub clock_impl: &'a mut CS,
    pub audio_impl: &'a mut AU,
    pub input_config: Option<TerminalConfig<In>>,
    pub output_config: Option<TerminalConfig<Out>>,
@@ -437,19 +564,11 @@ pub struct AudioClassConfig<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioCl
    _bus: PhantomData<B>,
 }

-impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>>
-    AudioClassConfig<'a, B, CS, AU>
-{
-    pub fn new(
-        speed: UsbSpeed,
-        device_category: FunctionCode,
-        clock_impl: &'a mut CS,
-        audio_impl: &'a mut AU,
-    ) -> Self {
+impl<'a, B: UsbBus, AU: AudioHandler<'a, B> + ClockSource> UsbAudioClassConfig<'a, B, AU> {
+    pub fn new(speed: UsbSpeed, device_category: FunctionCode, audio_impl: &'a mut AU) -> Self {
        Self {
            speed,
            device_category,
-            clock_impl,
            audio_impl,
            input_config: None,
            output_config: None,
@@ -474,7 +593,7 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>>
    }

    /// Allocate the various USB IDs, and build the class implementation
-    pub fn build(self, alloc: &'a UsbBusAllocator<B>) -> Result<AudioClass<'a, B, CS, AU>> {
+    pub fn build(self, alloc: &'a UsbBusAllocator<B>) -> Result<UsbAudioClass<'a, B, AU>> {
        let speed = self.speed;
        let (interval, fb_interval, audio_rate) = match speed {
            UsbSpeed::Full => (1, 1, 1000),
@@ -482,8 +601,8 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>>
            UsbSpeed::Low => return Err(Error::InvalidSpeed),
        };
        let max_rate = self
-            .clock_impl
-            .get_rates()
+            .audio_impl
+            .sample_rates()
            .unwrap()
            .iter()
            .max()
@@ -492,12 +611,11 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>>
        let control_iface = alloc.interface();

        let nominal_fb = UsbIsochronousFeedback::new_float(
-            self.clock_impl.get_sample_rate().to_f32().unwrap() / audio_rate.to_f32().unwrap(),
+            self.audio_impl.sample_rate().to_f32().unwrap() / audio_rate.to_f32().unwrap(),
        );

-        let mut ac = AudioClass {
+        let mut ac = UsbAudioClass {
            control_iface,
-            clock_impl: self.clock_impl,
            audio_impl: self.audio_impl,
            output: None,
            input: None,
@@ -663,9 +781,8 @@ impl<'a, B: UsbBus, D: EndpointDirection> AudioStream<'a, B, D> {
    }
 }

-pub struct AudioClass<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> {
+pub struct UsbAudioClass<'a, B: UsbBus, AU: AudioHandler<'a, B> + ClockSource> {
    control_iface: InterfaceNumber,
-    clock_impl: &'a mut CS,
    audio_impl: &'a mut AU,
    output: Option<AudioStream<'a, B, Out>>,
    input: Option<AudioStream<'a, B, In>>,
@@ -682,8 +799,8 @@ pub struct AudioClass<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a
    audio_rate: u32, // audio packet rate in hz
 }

-impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> UsbClass<B>
-    for AudioClass<'a, B, CS, AU>
+impl<'a, B: UsbBus, AU: AudioHandler<'a, B> + ClockSource> UsbClass<B>
+    for UsbAudioClass<'a, B, AU>
 {
    fn get_configuration_descriptors(
        &self,
@@ -715,7 +832,7 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> UsbClass<B>

        // BUILD CONFIGURATION DESCRIPTORS //
        let mut total_length: u16 = 9; // HEADER
-        let clock_desc = self.clock_impl.get_configuration_descriptor(1, None)?;
+        let clock_desc = self.audio_impl.clock_configuration_descriptor(1, None)?;
        total_length += clock_desc.size() as u16;
        let output_descs = match &self.output {
            Some(stream) => {
@@ -776,7 +893,7 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> UsbClass<B>

        // UAC2 4.7
        if let Some(descs) = additional_descs {
-            for desc in descs.into_iter() {
+            for desc in descs.iter() {
                desc.write_descriptor(writer)?;
            }
        }
@@ -831,10 +948,14 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> UsbClass<B>

    fn endpoint_in_complete(&mut self, addr: EndpointAddress) {
        debug!("EP {} IN complete", addr);
-        if let Some(fb_ep) = self.feedback.as_ref()
+        if let Some(_fb_ep) = self.feedback.as_ref()
            && addr.index() == self.fb_ep
        {
            self.emit_feedback();
+        } else if let Some(in_ep) = self.input.as_ref()
+            && addr.index() == self.in_ep
+        {
+            self.audio_impl.audio_data_tx(&in_ep.endpoint);
        } else {
            debug!("  unexpected IN on {}", addr);
        }
@@ -860,16 +981,24 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> UsbClass<B>
                        break;
                    }
                    Err(UsbError::WouldBlock) => break,
-                    Err(err) => {
-                        debug!("EP OUT error {:?}", err);
-                    }
+                    Err(_err) => {
+                        debug!("EP OUT error {:?}", _err);
                    }
                }
            }
        }
    }

-impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<'a, B, CS, AU> {
+    fn reset(&mut self) {
+        info!("usb reset");
+        self.audio_impl
+            .alternate_setting_changed(UsbDirection::In, 0);
+        self.audio_impl
+            .alternate_setting_changed(UsbDirection::Out, 0);
+    }
+}
+
+impl<'a, B: UsbBus, AU: AudioHandler<'a, B> + ClockSource> UsbAudioClass<'a, B, AU> {
    fn emit_feedback(&mut self) {
        if let Some(fb_ep) = self.feedback.as_ref() {
            if let Some(fb) = self.audio_impl.feedback(self.nominal_fb) {
@@ -878,11 +1007,11 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<
                    UsbSpeed::Low | UsbSpeed::Full => fb_ep.write(&fb.to_bytes_10_14()),
                    UsbSpeed::High | UsbSpeed::Super => fb_ep.write(&fb.to_bytes_12_13()),
                };
-                if let Err(e) = r {
-                    warn!("  feedback IN failed {:?}", e);
+                if let Err(_e) = r {
+                    warn!("  feedback IN failed {:?}", _e);
                }
            } else {
-                debug!("  feedback callback returned None")
+                debug!("  feedback callback returned None");
            }
        }
    }
@@ -908,11 +1037,11 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<

    fn class_request_out(&mut self, xfer: ControlOut<B>) {
        let req = xfer.request();
-        match (req.recipient, req.request.try_into()) {
-            (Recipient::Interface, Ok(ClassSpecificRequest::Cur)) => self.set_interface_cur(xfer),
-            (Recipient::Interface, Ok(ClassSpecificRequest::Range)) => {}
-            (Recipient::Endpoint, Ok(ClassSpecificRequest::Cur)) => self.set_endpoint_cur(xfer),
-            (Recipient::Endpoint, Ok(ClassSpecificRequest::Range)) => {}
+        match (req.recipient, req.request.into()) {
+            (Recipient::Interface, ClassSpecificRequest::Cur) => self.set_interface_cur(xfer),
+            (Recipient::Interface, ClassSpecificRequest::Range) => {}
+            (Recipient::Endpoint, ClassSpecificRequest::Cur) => self.set_endpoint_cur(xfer),
+            (Recipient::Endpoint, ClassSpecificRequest::Range) => {}
            _ => {
                debug!("   Unimplemented.");
            }
@@ -922,13 +1051,11 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<
    fn class_request_in(&mut self, xfer: ControlIn<B>) {
        let req = xfer.request();

-        match (req.recipient, req.request.try_into()) {
-            (Recipient::Interface, Ok(ClassSpecificRequest::Cur)) => self.get_interface_cur(xfer),
-            (Recipient::Interface, Ok(ClassSpecificRequest::Range)) => {
-                self.get_interface_range(xfer)
-            }
-            (Recipient::Endpoint, Ok(ClassSpecificRequest::Cur)) => self.get_endpoint_cur(xfer),
-            (Recipient::Endpoint, Ok(ClassSpecificRequest::Range)) => self.get_endpoint_range(xfer),
+        match (req.recipient, req.request.into()) {
+            (Recipient::Interface, ClassSpecificRequest::Cur) => self.get_interface_cur(xfer),
+            (Recipient::Interface, ClassSpecificRequest::Range) => self.get_interface_range(xfer),
+            (Recipient::Endpoint, ClassSpecificRequest::Cur) => self.get_endpoint_cur(xfer),
+            (Recipient::Endpoint, ClassSpecificRequest::Range) => self.get_endpoint_range(xfer),
            _ => {
                debug!("   Unimplemented.");
            }
@@ -942,19 +1069,21 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<

        debug!("  SET_ALT_INTERFACE {} {}", iface, alt_setting);

-        if self.input.is_some() && iface == self.in_iface {
-            let old_alt = self.input.as_ref().unwrap().alt_setting;
+        if let Some(input) = &mut self.input
+            && iface == self.in_iface
+        {
+            let old_alt = input.alt_setting;
            if old_alt != alt_setting {
-                self.clock_impl.alt_setting(alt_setting).ok();
                self.audio_impl
                    .alternate_setting_changed(UsbDirection::In, alt_setting);
-                self.input.as_mut().unwrap().alt_setting = alt_setting;
+                input.alt_setting = alt_setting;
+                // Start the IN cycle
+                self.audio_impl.audio_data_tx(&input.endpoint);
                xfer.accept().ok();
            }
        } else if self.output.is_some() && iface == self.out_iface {
            let old_alt = self.output.as_ref().unwrap().alt_setting;
            if old_alt != alt_setting {
-                self.clock_impl.alt_setting(alt_setting).ok();
                self.audio_impl
                    .alternate_setting_changed(UsbDirection::Out, alt_setting);
                // Start the IN cycle running
@@ -973,13 +1102,15 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<
        let req = xfer.request();
        let iface = req.index as u8;
        debug!("  GET_ALT_INTERFACE {}", iface);
-        if self.input.is_some() && iface == self.in_iface {
-            xfer.accept_with(&[self.input.as_ref().unwrap().alt_setting])
-                .ok();
+        if let Some(input) = self.input.as_ref()
+            && iface == self.in_iface
+        {
+            xfer.accept_with(&[input.alt_setting]).ok();
            return;
-        } else if self.output.is_some() && iface == self.out_iface {
-            xfer.accept_with(&[self.output.as_ref().unwrap().alt_setting])
-                .ok();
+        } else if let Some(output) = self.output.as_ref()
+            && iface == self.out_iface
+        {
+            xfer.accept_with(&[output.alt_setting]).ok();
            return;
        }
        debug!("   Unimplemented.");
@@ -1041,9 +1172,8 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<
        channel: u8,
        control: u8,
    ) {
-        match entity {
-            1 => return self.get_clock_cur(xfer, channel, control),
-            _ => {}
+        if entity == 1 {
+            return self.get_clock_cur(xfer, channel, control);
        }
        debug!("   Unimplemented.");
    }
@@ -1055,49 +1185,48 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<
        channel: u8,
        control: u8,
    ) {
-        match entity {
-            1 => return self.set_clock_cur(xfer, channel, control),
-            _ => {}
+        if entity == 1 {
+            return self.set_clock_cur(xfer, channel, control);
        }
        debug!("   Unimplemented.");
    }

    fn set_streaming_interface_cur(
        &mut self,
-        xfer: ControlOut<B>,
-        direction: UsbDirection,
-        entity: u8,
-        channel: u8,
-        control: u8,
+        _xfer: ControlOut<B>,
+        _direction: UsbDirection,
+        _entity: u8,
+        _channel: u8,
+        _control: u8,
    ) {
        debug!("   Unimplemented.");
    }

    fn get_endpoint_cur(&mut self, xfer: ControlIn<B>) {
        let req = xfer.request();
-        let entity = (req.index >> 8) as u8;
-        let interface = (req.index & 0xff) as u8;
-        let control = (req.value >> 8) as u8;
-        let channel = (req.value & 0xff) as u8;
+        let _entity = (req.index >> 8) as u8;
+        let _interface = (req.index & 0xff) as u8;
+        let _control = (req.value >> 8) as u8;
+        let _channel = (req.value & 0xff) as u8;

        debug!("   Unimplemented.");
    }
    fn get_endpoint_range(&mut self, xfer: ControlIn<B>) {
        let req = xfer.request();
-        let entity = (req.index >> 8) as u8;
-        let interface = (req.index & 0xff) as u8;
-        let control = (req.value >> 8) as u8;
-        let channel = (req.value & 0xff) as u8;
+        let _entity = (req.index >> 8) as u8;
+        let _interface = (req.index & 0xff) as u8;
+        let _control = (req.value >> 8) as u8;
+        let _channel = (req.value & 0xff) as u8;

        debug!("   Unimplemented.");
    }

    fn set_endpoint_cur(&mut self, xfer: ControlOut<B>) {
        let req = xfer.request();
-        let entity = (req.index >> 8) as u8;
-        let interface = (req.index & 0xff) as u8;
-        let control = (req.value >> 8) as u8;
-        let channel = (req.value & 0xff) as u8;
+        let _entity = (req.index >> 8) as u8;
+        let _interface = (req.index & 0xff) as u8;
+        let _control = (req.value >> 8) as u8;
+        let _channel = (req.value & 0xff) as u8;

        debug!("   Unimplemented.");
    }
@@ -1135,8 +1264,8 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<
        }
    }
    fn get_clock_cur(&mut self, xfer: ControlIn<B>, channel: u8, control: u8) {
-        match control.try_into() {
-            Ok(ClockSourceControlSelector::SamFreqControl) => {
+        match control.into() {
+            ClockSourceControlSelector::SamFreqControl => {
                debug!("   SamplingFreqControl");
                if channel != 0 {
                    error!(
@@ -1145,7 +1274,7 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<
                    );
                }
                xfer.accept(|mut buf| {
-                    let rate = self.clock_impl.get_sample_rate();
+                    let rate = self.audio_impl.sample_rate();

                    debug!("    {}", rate);
                    buf.write_u32::<LittleEndian>(rate)
@@ -1154,7 +1283,7 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<
                })
                .ok();
            }
-            Ok(ClockSourceControlSelector::ClockValidControl) => {
+            ClockSourceControlSelector::ClockValidControl => {
                debug!("   ClockValidControl");
                if channel != 0 {
                    error!(
@@ -1162,7 +1291,7 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<
                        channel
                    );
                }
-                xfer.accept(|mut buf| match self.clock_impl.get_clock_validity() {
+                xfer.accept(|mut buf| match self.audio_impl.clock_validity() {
                    Ok(valid) => {
                        debug!("    {}", valid);
                        buf.write_u8(valid as u8)
@@ -1180,8 +1309,8 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<
        }
    }
    fn set_clock_cur(&mut self, xfer: ControlOut<B>, channel: u8, control: u8) {
-        match control.try_into() {
-            Ok(ClockSourceControlSelector::SamFreqControl) => {
+        match control.into() {
+            ClockSourceControlSelector::SamFreqControl => {
                debug!("   SamplingFreqControl");
                if channel != 0 {
                    error!(
@@ -1192,13 +1321,13 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<
                match xfer.data().read_u32::<LittleEndian>() {
                    Ok(rate) => {
                        debug!("   SET SamplingFreqControl CUR {}", rate);
-                        self.clock_impl.set_sample_rate(rate).ok();
+                        self.audio_impl.set_sample_rate(rate).ok();
                        self.nominal_fb = UsbIsochronousFeedback::new_float(
                            rate.to_f32().unwrap() / self.audio_rate.to_f32().unwrap(),
                        );
                        xfer.accept().ok();
                    }
-                    Err(e) => {
+                    Err(_e) => {
                        error!("   SET SamplingFreqControl CUR ERROR BAD DATA");
                    }
                }
@@ -1209,8 +1338,8 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<
        }
    }
    fn get_clock_range(&mut self, xfer: ControlIn<B>, channel: u8, control: u8) {
-        match control.try_into() {
-            Ok(ClockSourceControlSelector::SamFreqControl) => {
+        match control.into() {
+            ClockSourceControlSelector::SamFreqControl => {
                debug!("   SamplingFreqControl");
                if channel != 0 {
                    error!(
@@ -1218,7 +1347,7 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<
                        channel
                    );
                }
-                xfer.accept(|mut buf| match self.clock_impl.get_rates() {
+                xfer.accept(|mut buf| match self.audio_impl.sample_rates() {
                    Ok(rates) => {
                        buf.write_u16::<LittleEndian>(rates.len() as u16)
                            .map_err(|_e| UsbError::BufferOverflow)?;
@@ -1253,3 +1382,15 @@ impl<'a, B: UsbBus, CS: UsbAudioClockImpl, AU: UsbAudioClass<'a, B>> AudioClass<
        }
    }
 }
+
+/// Set up a `UsbDeviceBuilder` with the device IDs for Usb Audio Class 2.0
+pub fn builder<'a, B: UsbBus>(
+    alloc: &'a UsbBusAllocator<B>,
+    vid_pid: UsbVidPid,
+) -> UsbDeviceBuilder<'a, B> {
+    UsbDeviceBuilder::new(alloc, vid_pid)
+        .composite_with_iads() // required by UAC2 4.6
+        .device_class(0xef) // required by UAC2 4.2
+        .device_sub_class(0x02) // required by UAC2 4.2
+        .device_protocol(0x01) // required by UAC2 4.2
+}
@@ -1,4 +1,5 @@
 // src/log.rs (or log/mod.rs)
+#[allow(unused_imports)]
 #[cfg(feature = "defmt")]
 pub use defmt::{debug, error, info, trace, warn};

@@ -6,25 +7,36 @@ pub use defmt::{debug, error, info, trace, warn};
 mod no_defmt {
    #[macro_export]
    macro_rules! trace {
-        ($($t:tt)*) => {};
+        ($($t:tt)*) => {
+            ()
+        };
    }
    #[macro_export]
    macro_rules! debug {
-        ($($t:tt)*) => {};
+        ($($t:tt)*) => {
+            ()
+        };
    }
    #[macro_export]
    macro_rules! info {
-        ($($t:tt)*) => {};
+        ($($t:tt)*) => {
+            ()
+        };
    }
    #[macro_export]
    macro_rules! warn {
-        ($($t:tt)*) => {};
+        ($($t:tt)*) => {
+            ()
+        };
    }
    #[macro_export]
    macro_rules! error {
-        ($($t:tt)*) => {};
+        ($($t:tt)*) => {
+            ()
+        };
    }
 }

+#[allow(unused_imports)]
 #[cfg(not(feature = "defmt"))]
 pub use no_defmt::*;
Author	SHA1	Message	Date
ktims	610ec6597d	exclude examples from package	2026-05-17 23:14:53 -07:00
ktims	98e0fb0927	add license	2026-05-17 23:11:32 -07:00
ktims	a848e236d4	add pre-commit	2026-05-17 22:58:14 -07:00
ktims	008c62318e	examples improvements	2026-05-17 22:58:00 -07:00
ktims	2b39987ef5	readme, doc comments, clippies	2026-05-17 22:53:33 -07:00
ktims	719d4391b8	examples: update README	2026-05-16 16:24:57 -07:00
ktims	ffbdef1b6d	lpc55s28-evk: add audio input	2026-05-16 16:07:45 -07:00
ktims	fb050c4a40	usbd_uac2: fix clippies, add builder, support IN data	2026-05-16 16:07:05 -07:00
ktims	24e0083090	factor into workspace, improve features & deps	2026-05-15 18:06:30 -07:00
ktims	08b1d10a92	update lpc55s28-evk for refactoring, improve comments etc.	2026-05-15 16:57:23 -07:00
ktims	d64bf1f204	refactor struct names, combine clock and audio handlers, builder pattern	2026-05-15 16:55:18 -07:00