Adds DMA support for ADC1 (#73)

* Adds DMA support for ADC

Author: thalesfragoso

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Added
 
+- Added DMA support for ADC1.
 - Added type aliases `Tx1` for `Tx<USART1>`, `RxDma1` for `RxDma<USART1, dma1::C5>`, etc.
 - Add ADC1 reading functions for channels 16 (temperature) and 17 (internal reference voltage)
 - Update existing ADC example according to ADC API changes

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, clocks);
+
+    // 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 +1,58 @@
+//! 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, clocks);
+
+    // 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();
+
+    // The read method consumes the buf and self, starts the adc and dma transfer and returns a
+    // RxDma struct. The wait method consumes the RxDma struct, waits for the whole transfer to be
+    // completed and then returns the updated buf and underlying adc_dma struct. For non blocking,
+    // one can call the is_done method of RxDma and only call wait after that method returns true.
+    let (_buf, adc_dma) = adc_dma.read(buf).wait();
+    asm::bkpt();
+    
+    // Consumes the AdcDma struct, restores adc configuration to previous state and returns the
+    // Adc struct in normal mode.
+    let (_adc1, _adc_ch0, _dma_ch1) = adc_dma.split();
+    asm::bkpt();
+
+    loop {}
+}

examples/adc.rs

@@ -29,10 +29,10 @@ fn main() -> ! {
     hprintln!("adc freq: {}", clocks.adcclk().0).unwrap();
 
     // Setup ADC
-    let mut adc1 = adc::Adc::adc1(p.ADC1, &mut rcc.apb2, clocks.adcclk());
+    let mut adc1 = adc::Adc::adc1(p.ADC1, &mut rcc.apb2, clocks);
 
     #[cfg(feature = "stm32f103")]
-    let mut adc2 = adc::Adc::adc2(p.ADC2, &mut rcc.apb2, clocks.adcclk());
+    let mut adc2 = adc::Adc::adc2(p.ADC2, &mut rcc.apb2, clocks);
 
     // Setup GPIOB
     let mut gpiob = p.GPIOB.split(&mut rcc.apb2);

examples/adc_temperature.rs

@@ -25,7 +25,7 @@ fn main() -> ! {
     hprintln!("adc freq: {}", clocks.adcclk().0).unwrap();
 
     // Setup ADC
-    let mut adc = adc::Adc::adc1(p.ADC1, &mut rcc.apb2, clocks.adcclk());
+    let mut adc = adc::Adc::adc1(p.ADC1, &mut rcc.apb2, clocks);
 
     // Read temperature sensor
     loop {