Merge pull request #2888 from FransUrbo/uart_r503

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

examples/rp/src/bin/uart_r503.rs

@@ -0,0 +1,158 @@
+#![no_std]
+#![no_main]
+
+use defmt::{debug, error, info};
+use embassy_executor::Spawner;
+use embassy_rp::bind_interrupts;
+use embassy_rp::peripherals::UART0;
+use embassy_rp::uart::{Config, DataBits, InterruptHandler as UARTInterruptHandler, Parity, StopBits, Uart};
+use embassy_time::{with_timeout, Duration, Timer};
+use heapless::Vec;
+use {defmt_rtt as _, panic_probe as _};
+
+bind_interrupts!(pub struct Irqs {
+    UART0_IRQ  => UARTInterruptHandler<UART0>;
+});
+
+const START: u16 = 0xEF01;
+const ADDRESS: u32 = 0xFFFFFFFF;
+
+// ================================================================================
+
+// Data package format
+// Name     Length          Description
+// ==========================================================================================================
+// Start    2 bytes         Fixed value of 0xEF01; High byte transferred first.
+// Address  4 bytes         Default value is 0xFFFFFFFF, which can be modified by command.
+//                          High byte transferred first and at wrong adder value, module
+//                          will reject to transfer.
+// PID      1 byte          01H     Command packet;
+//                          02H     Data packet; Data packet shall not appear alone in executing
+//                                  processs, must follow command packet or acknowledge packet.
+//                          07H     Acknowledge packet;
+//                          08H     End of Data packet.
+// LENGTH   2 bytes         Refers to the length of package content (command packets and data packets)
+//                          plus the length of Checksum (2 bytes). Unit is byte. Max length is 256 bytes.
+//                          And high byte is transferred first.
+// DATA     -               It can be commands, data, command’s parameters, acknowledge result, etc.
+//                          (fingerprint character value, template are all deemed as data);
+// SUM      2 bytes         The arithmetic sum of package identifier, package length and all package
+//                          contens. Overflowing bits are omitted. high byte is transferred first.
+
+// ================================================================================
+
+// Checksum is calculated on 'length (2 bytes) + data (??)'.
+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;
+}
+
+#[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;
+    config.parity = Parity::ParityNone;
+
+    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, mut rx) = uart.split();
+
+    let mut vec_buf: Vec<u8, 32> = heapless::Vec::new();
+    let mut data: Vec<u8, 32> = heapless::Vec::new();
+
+    let mut speeds: Vec<u8, 3> = heapless::Vec::new();
+    let _ = speeds.push(0xC8); // Slow
+    let _ = speeds.push(0x20); // Medium
+    let _ = speeds.push(0x02); // Fast
+
+    // Cycle through the three colours Red, Blue and Purple forever.
+    loop {
+        for colour in 1..=3 {
+            for speed in &speeds {
+                // Set the data first, because the length is dependent on that.
+                // However, we write the length bits before we do the data.
+                data.clear();
+                let _ = data.push(0x01); // ctrl=Breathing light
+                let _ = data.push(*speed);
+                let _ = data.push(colour as u8); // colour=Red, Blue, Purple
+                let _ = data.push(0x00); // times=Infinite
+
+                // Clear buffers
+                vec_buf.clear();
+
+                // START
+                let _ = vec_buf.extend_from_slice(&START.to_be_bytes()[..]);
+
+                // ADDRESS
+                let _ = vec_buf.extend_from_slice(&ADDRESS.to_be_bytes()[..]);
+
+                // PID
+                let _ = vec_buf.extend_from_slice(&[0x01]);
+
+                // LENGTH
+                let len: u16 = (1 + data.len() + 2).try_into().unwrap();
+                let _ = vec_buf.extend_from_slice(&len.to_be_bytes()[..]);
+
+                // COMMAND
+                let _ = vec_buf.push(0x35); // Command: AuraLedConfig
+
+                // DATA
+                let _ = vec_buf.extend_from_slice(&data);
+
+                // SUM
+                let chk = compute_checksum(vec_buf.clone());
+                let _ = vec_buf.extend_from_slice(&chk.to_be_bytes()[..]);
+
+                // =====
+
+                // Send command buffer.
+                let data_write: [u8; 16] = vec_buf.clone().into_array().unwrap();
+                debug!("  write='{:?}'", data_write[..]);
+                match tx.write(&data_write).await {
+                    Ok(..) => info!("Write successful."),
+                    Err(e) => error!("Write error: {:?}", e),
+                }
+
+                // =====
+
+                // Read command buffer.
+                let mut read_buf: [u8; 1] = [0; 1]; // Can only read one byte at a time!
+                let mut data_read: Vec<u8, 32> = heapless::Vec::new(); // Save buffer.
+
+                info!("Attempting read.");
+                loop {
+                    // Some commands, like `Img2Tz()` needs longer, but we hard-code this to 200ms
+                    // for this command.
+                    match with_timeout(Duration::from_millis(200), rx.read(&mut read_buf)).await {
+                        Ok(..) => {
+                            // Extract and save read byte.
+                            debug!("  r='{=u8:#04x}H' ({:03}D)", read_buf[0], read_buf[0]);
+                            let _ = data_read.push(read_buf[0]).unwrap();
+                        }
+                        Err(..) => break, // TimeoutError -> Ignore.
+                    }
+                }
+                info!("Read successful");
+                debug!("  read='{:?}'", data_read[..]);
+
+                Timer::after_secs(3).await;
+                info!("Changing speed.");
+            }
+
+            info!("Changing colour.");
+        }
+    }
+}