diff --git a/Cargo.toml b/Cargo.toml
index e48f8a9..d25a900 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,9 +4,10 @@ version = "0.1.0"
 edition = "2024"
 
 [features]
-default = ["ak4490", "dma"]
+default = ["cs4398", "hid"]
 ak4490 = []
-dma = []
+cs4398 = []
+hid = []
 
 [dependencies]
 bbqueue = "0.7.0"
diff --git a/src/dac/cs4398.rs b/src/dac/cs4398.rs
new file mode 100644
index 0000000..0c2e272
--- /dev/null
+++ b/src/dac/cs4398.rs
@@ -0,0 +1,67 @@
+use cortex_m::prelude::{_embedded_hal_blocking_i2c_Write, _embedded_hal_blocking_i2c_WriteRead};
+
+use crate::CodecPins;
+use crate::hal::prelude::*;
+use crate::traits::Dac;
+
+const CS4398_I2C_ADDRESS: u8 = 0x4f;
+
+#[repr(u8)]
+#[allow(dead_code)]
+enum RegisterAddress {
+    ChipId = 0x01,
+    ModeControl = 0x02,
+    VolMixInvControl = 0x03,
+    MuteControl = 0x04,
+    ChAVol = 0x05,
+    ChBVol = 0x06,
+    RampFiltControl = 0x07,
+    MiscControl = 0x08,
+    MiscControl2 = 0x09,
+}
+
+pub struct Cs4398Dac<T> {
+    i2c: T,
+    pins: CodecPins,
+}
+
+impl<T> Cs4398Dac<T>
+where
+    T: _embedded_hal_blocking_i2c_WriteRead + _embedded_hal_blocking_i2c_Write,
+{
+    #[inline]
+    fn write_reg(&mut self, reg: RegisterAddress, val: u8) {
+        self.i2c.write(CS4398_I2C_ADDRESS, &[reg as u8, val]).ok();
+    }
+    fn fm_for_rate(&self, rate: u32) -> u8 {
+        match rate {
+            r if r <= 50000 => 0b00,
+            r if r <= 100000 => 0b01,
+            _ => 0b10,
+            // DSD mode 0b11 is not used
+        }
+    }
+}
+
+impl<T> Dac<T> for Cs4398Dac<T>
+where
+    T: _embedded_hal_blocking_i2c_WriteRead + _embedded_hal_blocking_i2c_Write,
+{
+    fn new(i2c: T, pins: CodecPins) -> Self {
+        Cs4398Dac { i2c, pins }
+    }
+    fn init(&mut self) {
+        // reset
+        self.pins.reset.set_low().ok();
+        self.pins.reset.set_high().ok();
+        // power up, enable control port
+        self.write_reg(RegisterAddress::MiscControl, 1 << 6);
+        // set audio protocol to I2S, Single rate mode
+        self.write_reg(RegisterAddress::ModeControl, 1 << 4);
+        self.pins.reset.set_high().ok();
+    }
+    fn change_rate(&mut self, new_rate: u32) {
+        let mode_control = (1 << 4) | self.fm_for_rate(new_rate);
+        self.write_reg(RegisterAddress::ModeControl, mode_control);
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 7de751c..0d45fdd 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -44,6 +44,11 @@ pub mod dac {
     mod ak4490;
     pub use self::ak4490::Ak4490Dac as DacImpl;
 }
+#[cfg(feature = "cs4398")]
+pub mod dac {
+    mod cs4398;
+    pub use self::cs4398::Cs4398Dac as DacImpl;
+}
 
 mod traits;
 
@@ -334,7 +339,7 @@ impl<T: BbqHandle, D: Dac<I>, I, B: bus::UsbBus> UsbAudioClass<'_, B> for Audio<
         v = v.clamp(nominal_v - (1 << 12), nominal_v + (1 << 12));
 
         defmt::debug!(
-            "fill:{} err:{} int:{} fb:{=u32:x}",
+            "fill:{} err:{} int:{} fb:{=i32:x}",
             fill,
             error,
             integrator,
@@ -538,21 +543,6 @@ fn main() -> ! {
         pins: clock_sel_pins,
         cur_rate: SAMPLE_RATE,
     };
-
-    let mut usb_dev = UsbDeviceBuilder::new(&usb_bus, UsbVidPid(0x1209, 0xcc1d))
-        .composite_with_iads()
-        .strings(&[StringDescriptors::default()
-            .manufacturer("VE7XEN")
-            .product("Guac Tortilla")
-            .serial_number("123456789")])
-        .unwrap()
-        .max_packet_size_0(64)
-        .unwrap()
-        .device_class(0xef)
-        .device_sub_class(0x02)
-        .device_protocol(0x01)
-        .build();
-
     let config = AudioClassConfig::new(UsbSpeed::High, FunctionCode::Other, &mut clock, &mut audio)
         .with_output_config(TerminalConfig::new(
             2,
@@ -568,9 +558,21 @@ fn main() -> ! {
             LockDelay::Undefined(0),
             None,
         ));
-
     let mut uac2 = config.build(&usb_bus).unwrap();
 
+    let mut usb_dev = UsbDeviceBuilder::new(&usb_bus, UsbVidPid(0x1209, 0xcc1d))
+        .composite_with_iads()
+        .strings(&[StringDescriptors::default()
+            .manufacturer("VE7XEN")
+            .product("Guac Tortilla")
+            .serial_number("123456789")])
+        .unwrap()
+        .max_packet_size_0(64)
+        .unwrap()
+        .device_class(0xef)
+        .device_sub_class(0x02)
+        .device_protocol(0x01)
+        .build();
 
     defmt::info!("main loop");