Added PIO UART examples for rp to talk to an R503 fingerprint scanner.

examples/rp/src/bin/uart_r503.rs

@@ -0,0 +1,113 @@
+#![no_std]
+#![no_main]
+
+use defmt::{debug, info, unwrap};
+use embassy_executor::Spawner;
+use embassy_rp::bind_interrupts;
+use embassy_rp::peripherals::UART0;
+use embassy_rp::uart::{Async, Config, DataBits, InterruptHandler as UARTInterruptHandler, StopBits, Uart, UartRx};
+use embassy_time::Timer;
+use heapless::Vec;
+use {defmt_rtt as _, panic_probe as _};
+
+bind_interrupts!(pub struct Irqs {
+    UART0_IRQ  => UARTInterruptHandler<UART0>;	// Fingerprint scanner (TX)
+});
+
+const ADDRESS: u32 = 0xFFFFFFFF;
+const START: u16 = 0xEF01;
+
+// ================================================================================
+
+fn write_cmd_bytes(buf: &mut Vec<u8, 32>, bytes: &[u8]) {
+    let _ = buf.extend_from_slice(bytes);
+}
+
+fn compute_checksum(buf: Vec<u8, 32>) -> u16 {
+    let mut checksum = 0u16;
+
+    let check_end = buf.len();
+    let checked_bytes = &buf[6..check_end];
+    for byte in checked_bytes {
+        checksum += (*byte) as u16;
+    }
+    return checksum;
+}
+
+// NOTE: Doesn't work for some reason, it just hangs!
+#[embassy_executor::task]
+async fn reader(mut rx: UartRx<'static, UART0, Async>) {
+    loop {
+        let mut buf = [0; 32];
+        debug!("Attempting read..");
+
+        //rx.read(&mut buf).await.unwrap();
+        match rx.read(&mut buf).await {
+            Ok(v) => info!("Read successful: {:?}", v),
+            Err(e) => info!("Read error: {:?}", e),
+        }
+        info!("RX='{:?}'", buf);
+    }
+}
+
+#[embassy_executor::main]
+async fn main(spawner: Spawner) {
+    info!("Start");
+
+    let p = embassy_rp::init(Default::default());
+
+    // Initialize the fingerprint scanner.
+    let mut config = Config::default();
+    config.baudrate = 57600;
+    config.stop_bits = StopBits::STOP1;
+    config.data_bits = DataBits::DataBits8;
+
+    let (uart, tx_pin, tx_dma, rx_pin, rx_dma) = (p.UART0, p.PIN_16, p.DMA_CH0, p.PIN_17, p.DMA_CH1);
+    let uart = Uart::new(uart, tx_pin, rx_pin, Irqs, tx_dma, rx_dma, config);
+    let (mut tx, rx) = uart.split();
+
+    unwrap!(spawner.spawn(reader(rx)));
+    Timer::after_secs(1).await;
+
+    let mut vec_buf: Vec<u8, 32> = heapless::Vec::new();
+    {
+        // Clear buffers
+        vec_buf.clear();
+
+        // START
+        let _ = write_cmd_bytes(&mut vec_buf, &START.to_be_bytes()[..]);
+
+        // ADDRESS
+        let _ = write_cmd_bytes(&mut vec_buf, &ADDRESS.to_be_bytes()[..]);
+
+        // PID
+        let _ = vec_buf.push(0x01);
+
+        // LENGTH
+        let len = <usize as TryInto<u16>>::try_into(vec_buf.len()).unwrap() as u16;
+        let _ = write_cmd_bytes(&mut vec_buf, &len.to_be_bytes()[..]);
+
+        // COMMAND
+        let _ = vec_buf.push(0x35); // AuraLedConfig
+
+        // DATA
+        let _ = vec_buf.push(0x01); // ctrl=Breathing light
+        let _ = vec_buf.push(0x50); // speed=80
+        let _ = vec_buf.push(0x02); // colour=Blue
+        let _ = vec_buf.push(0x00); // times=Infinite
+
+        // SUM
+        let chk = compute_checksum(vec_buf.clone());
+        let _ = write_cmd_bytes(&mut vec_buf, &chk.to_be_bytes()[..]);
+
+        // =====
+
+        // Send command buffer.
+        let data: [u8; 16] = vec_buf.clone().into_array().unwrap();
+        debug!("data='{:?}'", data);
+        match tx.write(&data).await {
+            Ok(..) => info!("Write successful"),
+            Err(e) => info!("Write error: {:?}", e),
+        }
+    }
+}