simplify usb_uart example
@@ -15,15 +15,15 @@ use panic_probe as _; // print out panic messages
use embassy::executor::Spawner;
use embassy::io::{AsyncBufReadExt, AsyncWriteExt};
-use embassy::time::{Duration, Timer};
use embassy_nrf::usb::{State, Usb, UsbBus, UsbSerial};
use embassy_nrf::{interrupt, Peripherals};
use usb_device::device::{UsbDeviceBuilder, UsbVidPid};
#[embassy::main]
async fn main(_spawner: Spawner, p: Peripherals) {
- let mut tx_buffer = [0u8; 1024];
- let mut rx_buffer = [0u8; 640];
+ let mut rx_buffer = [0u8; 64];
+ // we send back input + cr + lf
+ let mut tx_buffer = [0u8; 66];
let usb_bus = UsbBus::new(p.USBD);
@@ -45,50 +45,50 @@ async fn main(_spawner: Spawner, p: Peripherals) {
let (mut reader, mut writer) = usb.as_ref().take_serial_0();
- unwrap!(writer.write_all(b"\r\nSend something\r\n").await);
-
info!("usb initialized!");
+ unwrap!(
+ writer
+ .write_all(b"\r\nInput returned upper cased on CR+LF\r\n")
+ .await
+ );
+
let mut buf = [0u8; 64];
loop {
let mut n = 0;
- let timed_out = {
- let newline_fut = async {
+
+ async {
loop {
let char = unwrap!(reader.read_byte().await);
- // echo input back to screen
- unwrap!(writer.write_byte(char).await);
- buf[n] = char;
- n += 1;
- if char == b'\n' || char == b'\r' || n == buf.len() {
+ // throw away, read more on cr, exit on lf
+ if char == b'\r' {
+ continue;
+ } else if char == b'\n' {
break;
}
- }
- };
- pin_mut!(newline_fut);
- let timeout_fut = Timer::after(Duration::from_ticks(32768 * 10));
+ buf[n] = char;
+ n += 1;
- // select chooses whichever returns first
- match select(newline_fut, timeout_fut).await {
- Either::Left(_) => false,
- Either::Right(_) => true,
+ // stop if we're out of room
+ if n == buf.len() {
+ break;
+ }
+ }
}
- };
+ .await;
- if timed_out {
- unwrap!(writer.write_all(b"\r\nTimed out\r\n").await);
- } else {
+ if n > 0 {
for char in buf[..n].iter_mut() {
// upper case
if 0x61 <= *char && *char <= 0x7a {
*char &= !0x20;
}
}
- unwrap!(writer.write_byte(b'\n').await);
unwrap!(writer.write_all(&buf[..n]).await);
- unwrap!(writer.write_byte(b'\n').await);
+ unwrap!(writer.write_all(b"\r\n").await);
+ unwrap!(writer.flush().await);
}
}
}
