4 files changed, 119 insertions, 12 deletions

diff --git a/embassy-stm32/build.rs b/embassy-stm32/build.rs
index ef152acd1..7860ee2ff 100644
--- a/embassy-stm32/build.rs
+++ b/embassy-stm32/build.rs
@@ -1009,6 +1009,10 @@ fn main() {
         (("dac", "CH1"), quote!(crate::dac::DacDma1)),
         (("dac", "CH2"), quote!(crate::dac::DacDma2)),
         (("timer", "UP"), quote!(crate::timer::UpDma)),
+        (("timer", "CH1"), quote!(crate::timer::Ch1Dma)),
+        (("timer", "CH2"), quote!(crate::timer::Ch2Dma)),
+        (("timer", "CH3"), quote!(crate::timer::Ch3Dma)),
+        (("timer", "CH4"), quote!(crate::timer::Ch4Dma)),
     ]
     .into();
 
@@ -1024,16 +1028,6 @@ fn main() {
                 }
 
                 if let Some(tr) = signals.get(&(regs.kind, ch.signal)) {
-                    // TIM6 of stm32f334 is special, DMA channel for TIM6 depending on SYSCFG state
-                    if chip_name.starts_with("stm32f334") && p.name == "TIM6" {
-                        continue;
-                    }
-
-                    // TIM6 of stm32f378 is special, DMA channel for TIM6 depending on SYSCFG state
-                    if chip_name.starts_with("stm32f378") && p.name == "TIM6" {
-                        continue;
-                    }
-
                     let peri = format_ident!("{}", p.name);
 
                     let channel = if let Some(channel) = &ch.channel {
diff --git a/embassy-stm32/src/timer/mod.rs b/embassy-stm32/src/timer/mod.rs
index d07fd2776..957098cde 100644
--- a/embassy-stm32/src/timer/mod.rs
+++ b/embassy-stm32/src/timer/mod.rs
@@ -311,6 +311,26 @@ pub(crate) mod sealed {
                 .ccmr_output(channel_index / 2)
                 .modify(|w| w.set_ocpe(channel_index % 2, preload));
         }
+
+        /// Get capture compare DMA selection
+        fn get_cc_dma_selection(&self) -> super::vals::Ccds {
+            Self::regs_gp16().cr2().read().ccds()
+        }
+
+        /// Set capture compare DMA selection
+        fn set_cc_dma_selection(&mut self, ccds: super::vals::Ccds) {
+            Self::regs_gp16().cr2().modify(|w| w.set_ccds(ccds))
+        }
+
+        /// Get capture compare DMA enable state
+        fn get_cc_dma_enable_state(&self, channel: Channel) -> bool {
+            Self::regs_gp16().dier().read().ccde(channel.index())
+        }
+
+        /// Set capture compare DMA enable state
+        fn set_cc_dma_enable_state(&mut self, channel: Channel, ccde: bool) {
+            Self::regs_gp16().dier().modify(|w| w.set_ccde(channel.index(), ccde))
+        }
     }
 
     /// Capture/Compare 16-bit timer instance with complementary pin support.
@@ -705,3 +725,8 @@ foreach_interrupt! {
 
 // Update Event trigger DMA for every timer
 dma_trait!(UpDma, Basic16bitInstance);
+
+dma_trait!(Ch1Dma, CaptureCompare16bitInstance);
+dma_trait!(Ch2Dma, CaptureCompare16bitInstance);
+dma_trait!(Ch3Dma, CaptureCompare16bitInstance);
+dma_trait!(Ch4Dma, CaptureCompare16bitInstance);
diff --git a/embassy-stm32/src/timer/simple_pwm.rs b/embassy-stm32/src/timer/simple_pwm.rs
index 80f10424c..665557354 100644
--- a/embassy-stm32/src/timer/simple_pwm.rs
+++ b/embassy-stm32/src/timer/simple_pwm.rs
@@ -155,7 +155,7 @@ impl<'d, T: CaptureCompare16bitInstance> SimplePwm<'d, T> {
     ///
     /// Note:  
     /// you will need to provide corresponding TIMx_UP DMA channel to use this method.
-    pub async fn gen_waveform(
+    pub async fn waveform_up(
         &mut self,
         dma: impl Peripheral<P = impl super::UpDma<T>>,
         channel: Channel,
@@ -221,6 +221,94 @@ impl<'d, T: CaptureCompare16bitInstance> SimplePwm<'d, T> {
     }
 }
 
+macro_rules! impl_waveform_chx {
+    ($fn_name:ident, $dma_ch:ident, $cc_ch:ident) => {
+        impl<'d, T: CaptureCompare16bitInstance> SimplePwm<'d, T> {
+            /// Generate a sequence of PWM waveform
+            ///
+            /// Note:
+            /// you will need to provide corresponding TIMx_CHy DMA channel to use this method.
+            pub async fn $fn_name(&mut self, dma: impl Peripheral<P = impl super::$dma_ch<T>>, duty: &[u16]) {
+                use super::vals::Ccds;
+
+                assert!(duty.iter().all(|v| *v <= self.get_max_duty()));
+
+                into_ref!(dma);
+
+                #[allow(clippy::let_unit_value)] // eg. stm32f334
+                let req = dma.request();
+
+                let cc_channel = super::Channel::$cc_ch;
+
+                let original_duty_state = self.get_duty(cc_channel);
+                let original_enable_state = self.is_enabled(cc_channel);
+                let original_cc_dma_on_update = self.inner.get_cc_dma_selection() == Ccds::ONUPDATE;
+                let original_cc_dma_enabled = self.inner.get_cc_dma_enable_state(cc_channel);
+
+                if original_cc_dma_on_update {
+                    self.inner.set_cc_dma_selection(Ccds::ONUPDATE)
+                }
+
+                if !original_cc_dma_enabled {
+                    self.inner.set_cc_dma_enable_state(cc_channel, true);
+                }
+
+                if !original_enable_state {
+                    self.enable(cc_channel);
+                }
+
+                unsafe {
+                    #[cfg(not(any(bdma, gpdma)))]
+                    use crate::dma::{Burst, FifoThreshold};
+                    use crate::dma::{Transfer, TransferOptions};
+
+                    let dma_transfer_option = TransferOptions {
+                        #[cfg(not(any(bdma, gpdma)))]
+                        fifo_threshold: Some(FifoThreshold::Full),
+                        #[cfg(not(any(bdma, gpdma)))]
+                        mburst: Burst::Incr8,
+                        ..Default::default()
+                    };
+
+                    Transfer::new_write(
+                        &mut dma,
+                        req,
+                        duty,
+                        T::regs_gp16().ccr(cc_channel.index()).as_ptr() as *mut _,
+                        dma_transfer_option,
+                    )
+                    .await
+                };
+
+                // restore output compare state
+                if !original_enable_state {
+                    self.disable(cc_channel);
+                }
+
+                self.set_duty(cc_channel, original_duty_state);
+
+                // Since DMA is closed before timer Capture Compare Event trigger DMA is turn off,
+                // this can almost always trigger a DMA FIFO error.
+                //
+                // optional TODO:
+                // clean FEIF after disable UDE
+                if !original_cc_dma_enabled {
+                    self.inner.set_cc_dma_enable_state(cc_channel, false);
+                }
+
+                if !original_cc_dma_on_update {
+                    self.inner.set_cc_dma_selection(Ccds::ONCOMPARE)
+                }
+            }
+        }
+    };
+}
+
+impl_waveform_chx!(waveform_ch1, Ch1Dma, Ch1);
+impl_waveform_chx!(waveform_ch2, Ch2Dma, Ch2);
+impl_waveform_chx!(waveform_ch3, Ch3Dma, Ch3);
+impl_waveform_chx!(waveform_ch4, Ch4Dma, Ch4);
+
 impl<'d, T: CaptureCompare16bitInstance> embedded_hal_02::Pwm for SimplePwm<'d, T> {
     type Channel = Channel;
     type Time = Hertz;
diff --git a/examples/stm32f4/src/bin/ws2812_pwm.rs b/examples/stm32f4/src/bin/ws2812_pwm.rs
index 239709253..6122cea2d 100644
--- a/examples/stm32f4/src/bin/ws2812_pwm.rs
+++ b/examples/stm32f4/src/bin/ws2812_pwm.rs
@@ -91,7 +91,7 @@ async fn main(_spawner: Spawner) {
     loop {
         for &color in color_list {
             // with &mut, we can easily reuse same DMA channel multiple times
-            ws2812_pwm.gen_waveform(&mut dp.DMA1_CH2, pwm_channel, color).await;
+            ws2812_pwm.waveform_up(&mut dp.DMA1_CH2, pwm_channel, color).await;
             // ws2812 need at least 50 us low level input to confirm the input data and change it's state
             Timer::after_micros(50).await;
             // wait until ticker tick