tests/rp: test error conditions for uart

tests/rp/src/bin/uart.rs

@@ -4,28 +4,165 @@
 
 use defmt::{assert_eq, *};
 use embassy_executor::Spawner;
-use embassy_rp::uart::{Config, Uart};
+use embassy_rp::gpio::{Level, Output};
+use embassy_rp::uart::{Blocking, Config, Error, Instance, Parity, Uart, UartRx};
+use embassy_time::{Duration, Timer};
 use {defmt_rtt as _, panic_probe as _};
 
+fn read<const N: usize>(uart: &mut Uart<'_, impl Instance, Blocking>) -> Result<[u8; N], Error> {
+    let mut buf = [255; N];
+    uart.blocking_read(&mut buf)?;
+    Ok(buf)
+}
+
+fn read1<const N: usize>(uart: &mut UartRx<'_, impl Instance, Blocking>) -> Result<[u8; N], Error> {
+    let mut buf = [255; N];
+    uart.blocking_read(&mut buf)?;
+    Ok(buf)
+}
+
+async fn send(pin: &mut Output<'_, impl embassy_rp::gpio::Pin>, v: u8, parity: Option<bool>) {
+    pin.set_low();
+    Timer::after(Duration::from_millis(1)).await;
+    for i in 0..8 {
+        if v & (1 << i) == 0 {
+            pin.set_low();
+        } else {
+            pin.set_high();
+        }
+        Timer::after(Duration::from_millis(1)).await;
+    }
+    if let Some(b) = parity {
+        if b {
+            pin.set_high();
+        } else {
+            pin.set_low();
+        }
+        Timer::after(Duration::from_millis(1)).await;
+    }
+    pin.set_high();
+    Timer::after(Duration::from_millis(1)).await;
+}
+
 #[embassy_executor::main]
 async fn main(_spawner: Spawner) {
     let p = embassy_rp::init(Default::default());
     info!("Hello World!");
 
-    let (tx, rx, uart) = (p.PIN_0, p.PIN_1, p.UART0);
+    let (mut tx, mut rx, mut uart) = (p.PIN_0, p.PIN_1, p.UART0);
 
+    {
         let config = Config::default();
-    let mut uart = Uart::new_blocking(uart, tx, rx, config);
+        let mut uart = Uart::new_blocking(&mut uart, &mut tx, &mut rx, config);
 
         // We can't send too many bytes, they have to fit in the FIFO.
         // This is because we aren't sending+receiving at the same time.
 
         let data = [0xC0, 0xDE];
         uart.blocking_write(&data).unwrap();
+        assert_eq!(read(&mut uart).unwrap(), data);
+    }
 
-    let mut buf = [0; 2];
+    info!("test overflow detection");
-    uart.blocking_read(&mut buf).unwrap();
+    {
-    assert_eq!(buf, data);
+        let config = Config::default();
+        let mut uart = Uart::new_blocking(&mut uart, &mut tx, &mut rx, config);
+
+        let data = [
+            1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
+            30, 31, 32,
+        ];
+        let overflow = [
+            101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116,
+        ];
+        uart.blocking_write(&data).unwrap();
+        uart.blocking_write(&overflow).unwrap();
+        while uart.busy() {}
+
+        // prefix in fifo is valid
+        assert_eq!(read(&mut uart).unwrap(), data);
+        // next received character causes overrun error and is discarded
+        uart.blocking_write(&[1, 2, 3]).unwrap();
+        assert_eq!(read::<1>(&mut uart).unwrap_err(), Error::Overrun);
+        assert_eq!(read(&mut uart).unwrap(), [2, 3]);
+    }
+
+    info!("test break detection");
+    {
+        let config = Config::default();
+        let mut uart = Uart::new_blocking(&mut uart, &mut tx, &mut rx, config);
+
+        // break on empty fifo
+        uart.send_break(20).await;
+        uart.blocking_write(&[64]).unwrap();
+        assert_eq!(read::<1>(&mut uart).unwrap_err(), Error::Break);
+        assert_eq!(read(&mut uart).unwrap(), [64]);
+
+        // break on partially filled fifo
+        uart.blocking_write(&[65; 2]).unwrap();
+        uart.send_break(20).await;
+        uart.blocking_write(&[66]).unwrap();
+        assert_eq!(read(&mut uart).unwrap(), [65; 2]);
+        assert_eq!(read::<1>(&mut uart).unwrap_err(), Error::Break);
+        assert_eq!(read(&mut uart).unwrap(), [66]);
+    }
+
+    // parity detection. here we bitbang to not require two uarts.
+    info!("test parity error detection");
+    {
+        let mut pin = Output::new(&mut tx, Level::High);
+        let mut config = Config::default();
+        config.baudrate = 1000;
+        config.parity = Parity::ParityEven;
+        let mut uart = UartRx::new_blocking(&mut uart, &mut rx, config);
+
+        async fn chr(pin: &mut Output<'_, impl embassy_rp::gpio::Pin>, v: u8, parity: u8) {
+            send(pin, v, Some(parity != 0)).await;
+        }
+
+        // first check that we can send correctly
+        chr(&mut pin, 64, 1).await;
+        assert_eq!(read1(&mut uart).unwrap(), [64]);
+
+        // all good, check real errors
+        chr(&mut pin, 2, 1).await;
+        chr(&mut pin, 3, 0).await;
+        chr(&mut pin, 4, 0).await;
+        chr(&mut pin, 5, 0).await;
+        assert_eq!(read1(&mut uart).unwrap(), [2, 3]);
+        assert_eq!(read1::<1>(&mut uart).unwrap_err(), Error::Parity);
+        assert_eq!(read1(&mut uart).unwrap(), [5]);
+    }
+
+    // framing error detection. here we bitbang because there's no other way.
+    info!("test framing error detection");
+    {
+        let mut pin = Output::new(&mut tx, Level::High);
+        let mut config = Config::default();
+        config.baudrate = 1000;
+        let mut uart = UartRx::new_blocking(&mut uart, &mut rx, config);
+
+        async fn chr(pin: &mut Output<'_, impl embassy_rp::gpio::Pin>, v: u8, good: bool) {
+            if good {
+                send(pin, v, None).await;
+            } else {
+                send(pin, v, Some(false)).await;
+            }
+        }
+
+        // first check that we can send correctly
+        chr(&mut pin, 64, true).await;
+        assert_eq!(read1(&mut uart).unwrap(), [64]);
+
+        // all good, check real errors
+        chr(&mut pin, 2, true).await;
+        chr(&mut pin, 3, true).await;
+        chr(&mut pin, 4, false).await;
+        chr(&mut pin, 5, true).await;
+        assert_eq!(read1(&mut uart).unwrap(), [2, 3]);
+        assert_eq!(read1::<1>(&mut uart).unwrap_err(), Error::Framing);
+        assert_eq!(read1(&mut uart).unwrap(), [5]);
+    }
 
     info!("Test OK");
     cortex_m::asm::bkpt();