Add example for ADC multi-channel conversions

Author: hannobraun

examples/adc_multi.rs

@@ -0,0 +1,88 @@
+//! Example showing continuous ADC with hardware trigger
+
+
+#![no_main]
+#![no_std]
+
+
+extern crate panic_halt;
+
+
+use core::{
+    fmt::Write as _,
+    pin::Pin,
+};
+
+
+use cortex_m_rt::entry;
+use stm32l0xx_hal::{
+    prelude::*,
+    adc,
+    dma::DMA,
+    pac::{
+        self,
+        tim2::cr2::MMS_A,
+    },
+    rcc,
+    serial,
+};
+
+
+#[entry]
+fn main() -> ! {
+    let dp = pac::Peripherals::take().unwrap();
+
+    let mut rcc   = dp.RCC.freeze(rcc::Config::hsi16());
+    let     adc   = dp.ADC.constrain(&mut rcc);
+    let mut dma   = DMA::new(dp.DMA1, &mut rcc);
+    let     gpioa = dp.GPIOA.split(&mut rcc);
+
+    // Connected to the host computer via the ST-LINK
+    let tx = gpioa.pa2;
+    let rx = gpioa.pa3;
+
+    // Initialize USART for test output
+    let (mut tx, _) = dp.USART2
+        .usart(
+            (tx, rx),
+            serial::Config::default()
+                .baudrate(115_200.bps()),
+            &mut rcc,
+        )
+        .unwrap()
+        .split();
+
+    // Create the buffer we're going to use for DMA.
+    //
+    // This is safe, since this is the main function, and it's only executed
+    // once. This means there is no other code accessing this `static`.
+    static mut BUFFER: [u16; 256] = [0; 256];
+    let buffer = Pin::new(unsafe { &mut BUFFER });
+
+    // Let's select some channels
+    let mut channels = adc::Channels::from(gpioa.pa0.into_analog());
+    channels.add(gpioa.pa1.into_analog());
+    channels.add(gpioa.pa4.into_analog());
+    channels.add(gpioa.pa5.into_analog());
+
+    // Start reading ADC values
+    let mut adc = adc.start(
+        channels,
+        Some(adc::Trigger::TIM2_TRGO),
+        &mut dma.handle,
+        dma.channels.channel1,
+        buffer,
+    );
+
+    // Enable trigger output for TIM2. This must happen after ADC has been
+    // configured.
+    dp.TIM2
+        .timer(1u32.hz(), &mut rcc)
+        .select_master_mode(MMS_A::UPDATE);
+
+    loop {
+        for val in adc.read_available().unwrap() {
+            write!(tx, "{}\r\n", val.unwrap()).unwrap();
+        }
+    }
+}