Adds DMA support for ADC

Author: thalesfragoso

examples/adc-dma-circ.rs

@@ -0,0 +1,61 @@
+//! ADC interface circular DMA RX transfer test
+
+#![no_main]
+#![no_std]
+
+use panic_halt as _;
+
+use cortex_m::{asm, singleton};
+
+use stm32f1xx_hal::{
+    prelude::*,
+    pac,
+    adc,
+    dma::Half,
+};
+use cortex_m_rt::entry;
+
+#[entry]
+fn main() -> ! {
+    // Aquire peripherals
+    let p = pac::Peripherals::take().unwrap();
+    let mut flash = p.FLASH.constrain();
+    let mut rcc = p.RCC.constrain();
+
+    // Configure ADC clocks
+    // Default value is the slowest possible ADC clock: PCLK2 / 8. Meanwhile ADC
+    // clock is configurable. So its frequency may be tweaked to meet certain
+    // practical needs. User specified value is be approximated using supported
+    // prescaler values 2/4/6/8.
+    let _clocks = rcc.cfgr.adcclk(2.mhz()).freeze(&mut flash.acr);
+
+    let dma_ch1 = p.DMA1.split(&mut rcc.ahb).1;
+
+    // Setup ADC
+    let adc1 = adc::Adc::adc1(p.ADC1, &mut rcc.apb2);
+
+    // Setup GPIOA
+    let mut gpioa = p.GPIOA.split(&mut rcc.apb2);
+
+    // Configure pa0 as an analog input
+    let adc_ch0 = gpioa.pa0.into_analog(&mut gpioa.crl);
+
+    let adc_dma = adc1.with_dma(adc_ch0, dma_ch1);
+    let buf = singleton!(: [[u16; 8]; 2] = [[0; 8]; 2]).unwrap();
+
+    let mut circ_buffer = adc_dma.circ_read(buf);
+
+    while circ_buffer.readable_half().unwrap() != Half::First {}
+
+    let _first_half = circ_buffer.peek(|half, _| *half).unwrap();
+
+    while circ_buffer.readable_half().unwrap() != Half::Second {}
+
+    let _second_half = circ_buffer.peek(|half, _| *half).unwrap();
+
+    let (_buf, adc_dma) = circ_buffer.stop();
+    let (_adc1, _adc_ch0, _dma_ch1) = adc_dma.split();
+    asm::bkpt();
+
+    loop {}
+}

examples/adc-dma-rx.rs

@@ -0,0 +1,52 @@
+//! ADC interface DMA RX transfer test
+
+#![no_main]
+#![no_std]
+
+use panic_halt as _;
+
+use cortex_m::{asm, singleton};
+
+use stm32f1xx_hal::{
+    prelude::*,
+    pac,
+    adc,
+};
+use cortex_m_rt::entry;
+
+#[entry]
+fn main() -> ! {
+    // Aquire peripherals
+    let p = pac::Peripherals::take().unwrap();
+    let mut flash = p.FLASH.constrain();
+    let mut rcc = p.RCC.constrain();
+
+    // Configure ADC clocks
+    // Default value is the slowest possible ADC clock: PCLK2 / 8. Meanwhile ADC
+    // clock is configurable. So its frequency may be tweaked to meet certain
+    // practical needs. User specified value is be approximated using supported
+    // prescaler values 2/4/6/8.
+    let _clocks = rcc.cfgr.adcclk(2.mhz()).freeze(&mut flash.acr);
+
+    let dma_ch1 = p.DMA1.split(&mut rcc.ahb).1;
+
+    // Setup ADC
+    let adc1 = adc::Adc::adc1(p.ADC1, &mut rcc.apb2);
+
+    // Setup GPIOA
+    let mut gpioa = p.GPIOA.split(&mut rcc.apb2);
+
+    // Configure pa0 as an analog input
+    let adc_ch0 = gpioa.pa0.into_analog(&mut gpioa.crl);
+
+    let adc_dma = adc1.with_dma(adc_ch0, dma_ch1);
+    let buf = singleton!(: [u16; 8] = [0; 8]).unwrap();
+
+    let (_buf, adc_dma) = adc_dma.read(buf).wait();
+    asm::bkpt();
+    
+    let (_adc1, _adc_ch0, _dma_ch1) = adc_dma.split();
+    asm::bkpt();
+
+    loop {}
+}

src/adc.rs

@@ -6,6 +6,8 @@ use crate::gpio::Analog;
 use crate::gpio::{gpioa, gpiob, gpioc};
 use crate::rcc::APB2;
 use crate::time::Hertz;
+use crate::dma::{Receive, TransferPayload, dma1::C1, CircBuffer, Transfer, W, RxDma};
+use core::sync::atomic::{self, Ordering};
 
 use crate::stm32::ADC1;
 #[cfg(any(
@@ -490,3 +492,118 @@ adc_hal! {
         adc2rst
     ),
 }
+
+pub struct AdcPayload<PIN: Channel<ADC1>> {
+    adc: Adc<ADC1>,
+    pin: PIN,
+}
+
+pub type AdcDma<PIN> = RxDma<AdcPayload<PIN>, C1>;
+
+impl<PIN> Receive for AdcDma<PIN> where PIN: Channel<ADC1> {
+    type RxChannel = C1;
+    type TransmittedWord = u16;
+}
+
+impl<PIN> TransferPayload for AdcDma<PIN> where PIN: Channel<ADC1> {
+    fn start(&mut self) {
+        self.channel.start();
+        self.payload.adc.rb.cr2.modify(|_, w| w.cont().set_bit());
+        self.payload.adc.rb.cr2.modify(|_, w| w.adon().set_bit());
+    }
+    fn stop(&mut self) {
+        self.channel.stop();
+        self.payload.adc.rb.cr2.modify(|_, w| w.cont().clear_bit());
+    }
+}
+
+impl Adc<ADC1> {
+    pub fn with_dma<PIN>(mut self, pin: PIN, dma_ch: C1) -> AdcDma<PIN>
+    where
+        PIN: Channel<ADC1, ID = u8>,
+    {
+        self.rb.cr1.modify(|_, w| w.discen().clear_bit());
+        self.rb.cr2.modify(|_, w| w.align().bit(self.align.into()));
+        self.set_chan_smps(PIN::channel());
+        self.rb.sqr3.modify(|_, w| unsafe { w.sq1().bits(PIN::channel()) });
+        self.rb.cr2.modify(|_, w| w.dma().set_bit());
+
+        let payload = AdcPayload {
+            adc: self,
+            pin,
+        };
+        RxDma {
+            payload,
+            channel: dma_ch,
+        }
+    }
+}
+
+impl<PIN> AdcDma<PIN> where PIN: Channel<ADC1> {
+    pub fn split(mut self) -> (Adc<ADC1>, PIN, C1) {
+        self.stop();
+
+        let AdcDma {payload, channel} = self;
+        payload.adc.rb.cr2.modify(|_, w| w.dma().clear_bit());
+        payload.adc.rb.cr1.modify(|_, w| w.discen().set_bit());
+
+        (payload.adc, payload.pin, channel)
+    }
+}
+
+impl<B, PIN> crate::dma::CircReadDma<B, u16> for AdcDma<PIN> 
+where 
+    B: AsMut<[u16]>,
+    PIN: Channel<ADC1>,
+{
+    fn circ_read(mut self, buffer: &'static mut [B; 2]) -> CircBuffer<B, Self> {
+        {
+            let buffer = buffer[0].as_mut();
+            self.channel.set_peripheral_address(unsafe{ &(*ADC1::ptr()).dr as *const _ as u32 }, false);
+            self.channel.set_memory_address(buffer.as_ptr() as u32, true);
+            self.channel.set_transfer_length(buffer.len() * 2);
+
+            atomic::compiler_fence(Ordering::Release);
+
+            self.channel.ch().cr.modify(|_, w| { w
+                .mem2mem() .clear_bit()
+                .pl()      .medium()
+                .msize()   .bit16()
+                .psize()   .bit16()
+                .circ()    .set_bit()
+                .dir()     .clear_bit()
+            });
+        }
+
+        self.start();
+
+        CircBuffer::new(buffer, self)
+    }
+}
+
+impl<B, PIN> crate::dma::ReadDma<B, u16> for AdcDma<PIN>
+where 
+    B: AsMut<[u16]>,
+    PIN: Channel<ADC1>,
+{
+    fn read(mut self, buffer: &'static mut B) -> Transfer<W, &'static mut B, Self> {
+        {
+            let buffer = buffer.as_mut();
+            self.channel.set_peripheral_address(unsafe{ &(*ADC1::ptr()).dr as *const _ as u32 }, false);
+            self.channel.set_memory_address(buffer.as_ptr() as u32, true);
+            self.channel.set_transfer_length(buffer.len());
+        }
+        atomic::compiler_fence(Ordering::Release);
+        self.channel.ch().cr.modify(|_, w| { w
+            .mem2mem() .clear_bit()
+            .pl()      .medium()
+            .msize()   .bit16()
+            .psize()   .bit16()
+            .circ()    .clear_bit()
+            .dir()     .clear_bit()
+        });
+        self.start();
+
+        Transfer::w(buffer, self)
+    }
+}