diff --git a/ch32v-insert-coin/Cargo.lock b/ch32v-insert-coin/Cargo.lock
index 3624407..028f1cb 100644
--- a/ch32v-insert-coin/Cargo.lock
+++ b/ch32v-insert-coin/Cargo.lock
@@ -2,6 +2,10 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "adpcm-pwm-dac"
+version = "0.1.0"
+
 [[package]]
 name = "autocfg"
 version = "1.5.0"
@@ -66,9 +70,9 @@ dependencies = [
 name = "ch32v-insert-coin"
 version = "0.1.0"
 dependencies = [
+ "adpcm-pwm-dac",
  "ch32-hal",
  "embassy-executor",
- "embassy-time",
  "embedded-hal 1.0.0",
  "panic-halt",
  "qingke-rt",
diff --git a/ch32v-insert-coin/Cargo.toml b/ch32v-insert-coin/Cargo.toml
index b7a1a06..566357b 100644
--- a/ch32v-insert-coin/Cargo.toml
+++ b/ch32v-insert-coin/Cargo.toml
@@ -11,21 +11,20 @@ ch32-hal = { path = "ext/ch32-hal/", features = [
     "time-driver-tim2",
     "rt",
 ] }
+
 embassy-executor = { version = "0.7.0", features = [
     "arch-spin",
     "executor-thread",
     "task-arena-size-128", # or better use nightly, but fails on recent Rust versions
-    #"nightly",
 ] }
 
-embassy-time = "0.4.0"
 panic-halt = "1.0"
 
 embedded-hal = "1.0.0"
 
 qingke-rt = { version = "*", features = ["highcode"] }
 
-
+adpcm-pwm-dac = { path = "ext/adpcm-pwm-dac/" }
 
 [profile.release]
 strip = false   # symbols are not flashed to the microcontroller, so don't strip them.
diff --git a/ch32v-insert-coin/ext/adpcm-pwm-dac b/ch32v-insert-coin/ext/adpcm-pwm-dac
index d06329a..8502ed7 160000
--- a/ch32v-insert-coin/ext/adpcm-pwm-dac
+++ b/ch32v-insert-coin/ext/adpcm-pwm-dac
@@ -1 +1 @@
-Subproject commit d06329a7259f126987355045281cbdf292258710
+Subproject commit 8502ed75bf8d3e8df1eb5f1b5576079f55c6e13e
diff --git a/ch32v-insert-coin/src/main.rs b/ch32v-insert-coin/src/main.rs
index 7fc4b30..3ff3278 100644
--- a/ch32v-insert-coin/src/main.rs
+++ b/ch32v-insert-coin/src/main.rs
@@ -6,7 +6,30 @@
 use hal::delay::Delay;
 use hal::gpio::{AnyPin, Level, Output, Pin};
 use {ch32_hal as hal};
+use hal::time::Hertz;
+use hal::timer::low_level::CountingMode;
+use hal::timer::simple_pwm::{PwmPin, SimplePwm};
+use hal::timer::{Channel, GeneralInstance16bit};
 
+// const DAC_DATA: [u8; 4] = [0x0, 0x80, 0xFF, 0x80];
+const DAC_DATA: [u8; 8] = [0, 25, 50, 75, 100, 75, 50, 25];
+
+struct SimplePwmDacPin<'d, T: GeneralInstance16bit>{
+    pin: SimplePwm<'d, T>,
+    ch: Channel,
+}
+
+
+use adpcm_pwm_dac::{interface::DacInterface, dac::Dac};
+
+impl<T> DacInterface for SimplePwmDacPin<'_, T> 
+where T: GeneralInstance16bit {
+    fn write_amplitude(&mut self, amplitude: u8) {
+        let max_duty = self.pin.get_max_duty();
+        let dc = amplitude as u32 * max_duty / 100;
+        self.pin.set_duty(self.ch, dc);
+    }
+}
 
 fn blink(pin: AnyPin, interval_ms: u64) {
     let mut led = Output::new(pin, Level::Low, Default::default());
@@ -26,14 +49,61 @@ fn blink(pin: AnyPin, interval_ms: u64) {
     }
 }
 
+fn pwm_blink<T: GeneralInstance16bit>(mut pwm_dac_pin: SimplePwmDacPin<'_, T>) {
+    let mut delay = Delay;
+
+
+
+    let interval_ms = 1000u32;
+    loop {
+        pwm_dac_pin.write_amplitude(75);
+        delay.delay_ms((interval_ms/2) as u32);
+        pwm_dac_pin.write_amplitude(50);
+        delay.delay_ms((interval_ms/2) as u32);
+        pwm_dac_pin.write_amplitude(25);
+        delay.delay_ms((interval_ms/2) as u32);
+    }
+}
+
+fn dac_run<T: DacInterface>(mut dac: Dac<'_, T>, sample_rate: usize) {
+    let mut delay = Delay;
+
+
+    dac.load_data(&DAC_DATA);
+
+    let interval_us = 1000000/sample_rate as u32;
+    loop {
+        dac.output_next();
+        delay.delay_us(interval_us);
+    }
+}
+
 #[qingke_rt::entry]
 fn main() -> ! {
     let mut config = hal::Config::default();
     config.rcc = hal::rcc::Config::SYSCLK_FREQ_48MHZ_HSE;
     let p = hal::init(config);
+    
 
-    let mut delay = Delay;
+    let pin = PwmPin::new_ch4::<0>(p.PC4);
+    let ch = hal::timer::Channel::Ch4;
+    let mut pwm = SimplePwm::new(
+        p.TIM1,
+        None,
+        None,
+        None,
+        Some(pin),
+        Hertz::khz(24),
+        CountingMode::default(),
+    );
+    pwm.enable(ch);
 
+
+    let mut pwm_dac_pin = SimplePwmDacPin{pin: pwm, ch};
+    let mut dac = Dac::new(pwm_dac_pin);
+    let sample_rate_hz = 440 * DAC_DATA.len();
+    // pwm_blink(pwm_dac_pin);
+    dac_run(dac, sample_rate_hz);
     blink(p.PD6.degrade(), 100);
     loop{};
 }