nrf/buffered_uarte: add test for recovering from buffer full.

tests/nrf/src/bin/buffered_uart_full.rs

@@ -0,0 +1,72 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+teleprobe_meta::target!(b"nrf52840-dk");
+
+use defmt::{assert_eq, *};
+use embassy_executor::Spawner;
+use embassy_nrf::buffered_uarte::{self, BufferedUarte};
+use embassy_nrf::{bind_interrupts, peripherals, uarte};
+use embedded_io_async::{Read, Write};
+use {defmt_rtt as _, panic_probe as _};
+
+bind_interrupts!(struct Irqs {
+    UARTE0_UART0 => buffered_uarte::InterruptHandler<peripherals::UARTE0>;
+});
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let p = embassy_nrf::init(Default::default());
+    let mut config = uarte::Config::default();
+    config.parity = uarte::Parity::EXCLUDED;
+    config.baudrate = uarte::Baudrate::BAUD1M;
+
+    let mut tx_buffer = [0u8; 1024];
+    let mut rx_buffer = [0u8; 1024];
+
+    let mut u = BufferedUarte::new(
+        p.UARTE0,
+        p.TIMER0,
+        p.PPI_CH0,
+        p.PPI_CH1,
+        p.PPI_GROUP0,
+        Irqs,
+        p.P1_03,
+        p.P1_02,
+        config.clone(),
+        &mut rx_buffer,
+        &mut tx_buffer,
+    );
+
+    info!("uarte initialized!");
+
+    let (mut rx, mut tx) = u.split();
+
+    let mut buf = [0; 1024];
+    for (j, b) in buf.iter_mut().enumerate() {
+        *b = j as u8;
+    }
+
+    // Write 1024b. This causes the rx buffer to get exactly full.
+    unwrap!(tx.write_all(&buf).await);
+    unwrap!(tx.flush().await);
+
+    // Read those 1024b.
+    unwrap!(rx.read_exact(&mut buf).await);
+    for (j, b) in buf.iter().enumerate() {
+        assert_eq!(*b, j as u8);
+    }
+
+    // The buffer should now be unclogged. Write 1024b again.
+    unwrap!(tx.write_all(&buf).await);
+    unwrap!(tx.flush().await);
+
+    // Read should work again.
+    unwrap!(rx.read_exact(&mut buf).await);
+    for (j, b) in buf.iter().enumerate() {
+        assert_eq!(*b, j as u8);
+    }
+
+    info!("Test OK");
+    cortex_m::asm::bkpt();
+}