Add serial example using RTIC

Author: hannobraun

Cargo.toml

@@ -100,6 +100,10 @@ required-features = ["rt"]
 name = "rtic_frame_serial_dma"
 required-features = ["rt", "stm32l4x2"]
 
+[[example]]
+name = "serial_echo_rtic"
+required-features = ["rt", "stm32l4x3"]
+
 [[example]]
 name = "timer"
 required-features = ["rt"]

examples/serial_echo_rtic.rs

@@ -0,0 +1,68 @@
+#![no_main]
+#![no_std]
+
+extern crate panic_halt;
+
+use nb::block;
+use stm32l4xx_hal::{
+    prelude::*,
+    pac::{
+        self,
+        USART2,
+    },
+    serial::{
+        self,
+        Config,
+        Serial,
+    },
+};
+
+#[rtic::app(device = stm32l4xx_hal::pac)]
+const APP: () = {
+    struct Resources {
+        rx: serial::Rx<USART2>,
+        tx: serial::Tx<USART2>,
+    }
+
+    #[init]
+    fn init(_: init::Context) -> init::LateResources {
+        let p = pac::Peripherals::take().unwrap();
+
+        let mut rcc = p.RCC.constrain();
+        let mut flash = p.FLASH.constrain();
+        let mut pwr = p.PWR.constrain(&mut rcc.apb1r1);
+
+        let clocks = rcc.cfgr.freeze(&mut flash.acr, &mut pwr);
+
+        let mut gpioa = p.GPIOA.split(&mut rcc.ahb2);
+
+        let tx_pin = gpioa.pa2.into_af7(&mut gpioa.moder, &mut gpioa.afrl);
+        let rx_pin = gpioa.pa3.into_af7(&mut gpioa.moder, &mut gpioa.afrl);
+
+        let serial = Serial::usart2(
+            p.USART2,
+            (tx_pin, rx_pin),
+            Config::default()
+                .baudrate(115_200.bps()),
+            clocks,
+            &mut rcc.apb1r1,
+        );
+        let (tx, rx) = serial.split();
+
+        init::LateResources {
+            rx,
+            tx,
+        }
+    }
+
+    #[idle(resources = [rx, tx])]
+    fn idle(cx: idle::Context) -> ! {
+        let rx = cx.resources.rx;
+        let tx = cx.resources.tx;
+
+        loop {
+            let b = block!(rx.read()).unwrap();
+            block!(tx.write(b)).unwrap();
+        }
+    }
+};