wip: adding basic ringbuffered structure

2 files changed, 48 insertions, 0 deletions

diff --git a/embassy-stm32/src/timer/mod.rs b/embassy-stm32/src/timer/mod.rs
index 804d1ef37..aef3598f1 100644
--- a/embassy-stm32/src/timer/mod.rs
+++ b/embassy-stm32/src/timer/mod.rs
@@ -13,6 +13,7 @@ pub mod one_pulse;
 pub mod pwm_input;
 pub mod qei;
 pub mod simple_pwm;
+pub mod ringbuffered;
 
 use crate::interrupt;
 use crate::rcc::RccPeripheral;
diff --git a/embassy-stm32/src/timer/ringbuffered.rs b/embassy-stm32/src/timer/ringbuffered.rs
new file mode 100644
index 000000000..d20c5d532
--- /dev/null
+++ b/embassy-stm32/src/timer/ringbuffered.rs
@@ -0,0 +1,47 @@
+//! RingBuffered PWM driver.
+
+use core::mem::ManuallyDrop;
+
+use super::low_level::Timer;
+use super::{Channel, GeneralInstance4Channel, TimerChannel, TimerPin};
+use crate::Peri;
+use crate::dma::ringbuffer::WritableDmaRingBuffer;
+use super::simple_pwm::SimplePwm;
+
+pub struct RingBufferedPwmChannel<'d, T: GeneralInstance4Channel> {
+    timer: ManuallyDrop<Timer<'d, T>>,
+    ring_buf: WritableDmaRingBuffer<'d, u8>,
+    channel: Channel,
+}
+
+/// A group of four [`SimplePwmChannel`]s, obtained from [`SimplePwm::split`].
+pub struct RingBufferedPwmChannels<'d, T: GeneralInstance4Channel> {
+    /// Channel 1
+    pub ch1: RingBufferedPwmChannel<'d, T>,
+    /// Channel 2
+    pub ch2: RingBufferedPwmChannel<'d, T>,
+    /// Channel 3
+    pub ch3: RingBufferedPwmChannel<'d, T>,
+    /// Channel 4
+    pub ch4: RingBufferedPwmChannel<'d, T>,
+}
+
+/// Simple PWM driver.
+pub struct RingBufferedPwm<'d, T: GeneralInstance4Channel> {
+    inner: Timer<'d, T>,
+}
+
+impl<'d, T: GeneralInstance4Channel> SimplePwm<'d, T> {
+    pub fn into_ring_buffered_channel<C: TimerChannel>(mut self, tx_dma: Peri<'_, impl super::Dma<T, C>>, dma_buf: &'d mut [u8]) -> RingBufferedPwmChannel<'d> {
+        assert!(!dma_buf.is_empty() && dma_buf.len() <= 0xFFFF);
+        let ring_buf = WritableDmaRingBuffer::new(dma_buf);
+        let channel = C::CHANNEL;
+        RingBufferedPwmChannel {
+            timer: unsafe { self.inner.clone_unchecked() },
+            channel,
+            ring_buf
+        }
+
+        // let ring_buf = WriteableRingBuffer::new();
+    }
+}