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#![no_std]
#![no_main]
use embassy_executor::Spawner;
use hal::lpuart::{Blocking, Config, Lpuart};
use {defmt_rtt as _, embassy_mcxa as hal, panic_probe as _};
/// Simple helper to write a byte as hex to UART
fn write_hex_byte(uart: &mut Lpuart<'_, Blocking>, byte: u8) {
const HEX_DIGITS: &[u8] = b"0123456789ABCDEF";
uart.write_byte(HEX_DIGITS[(byte >> 4) as usize]);
uart.write_byte(HEX_DIGITS[(byte & 0xF) as usize]);
}
#[embassy_executor::main]
async fn main(_spawner: Spawner) {
let p = hal::init(hal::config::Config::default());
defmt::info!("boot");
// Create UART configuration
let config = Config {
baudrate_bps: 115_200,
enable_tx: true,
enable_rx: true,
..Default::default()
};
// Create UART instance using LPUART2 with PIO2_2 as TX and PIO2_3 as RX
unsafe {
embassy_mcxa_examples::init_uart2_pins(hal::pac());
}
let mut uart = Lpuart::new_blocking(
p.LPUART2, // Peripheral
p.PIO2_2, // TX pin
p.PIO2_3, // RX pin
config,
)
.unwrap();
// Print welcome message before any async delays to guarantee early console output
uart.write_str_blocking("\r\n=== MCXA276 UART Echo Demo ===\r\n");
uart.write_str_blocking("Available commands:\r\n");
uart.write_str_blocking(" help - Show this help\r\n");
uart.write_str_blocking(" echo <text> - Echo back the text\r\n");
uart.write_str_blocking(" hex <byte> - Display byte in hex (0-255)\r\n");
uart.write_str_blocking("Type a command: ");
let mut buffer = [0u8; 64];
let mut buf_idx = 0;
loop {
// Read a byte from UART
let byte = uart.read_byte_blocking();
// Echo the character back
if byte == b'\r' || byte == b'\n' {
// Enter pressed - process command
uart.write_str_blocking("\r\n");
if buf_idx > 0 {
let command = &buffer[0..buf_idx];
if command == b"help" {
uart.write_str_blocking("Available commands:\r\n");
uart.write_str_blocking(" help - Show this help\r\n");
uart.write_str_blocking(" echo <text> - Echo back the text\r\n");
uart.write_str_blocking(" hex <byte> - Display byte in hex (0-255)\r\n");
} else if command.starts_with(b"echo ") && command.len() > 5 {
uart.write_str_blocking("Echo: ");
uart.write_str_blocking(core::str::from_utf8(&command[5..]).unwrap_or(""));
uart.write_str_blocking("\r\n");
} else if command.starts_with(b"hex ") && command.len() > 4 {
// Parse the byte value
let num_str = &command[4..];
if let Ok(num) = parse_u8(num_str) {
uart.write_str_blocking("Hex: 0x");
write_hex_byte(&mut uart, num);
uart.write_str_blocking("\r\n");
} else {
uart.write_str_blocking("Invalid number for hex command\r\n");
}
} else if !command.is_empty() {
uart.write_str_blocking("Unknown command: ");
uart.write_str_blocking(core::str::from_utf8(command).unwrap_or(""));
uart.write_str_blocking("\r\n");
}
}
// Reset buffer and prompt
buf_idx = 0;
uart.write_str_blocking("Type a command: ");
} else if byte == 8 || byte == 127 {
// Backspace
if buf_idx > 0 {
buf_idx -= 1;
uart.write_str_blocking("\x08 \x08"); // Erase character
}
} else if buf_idx < buffer.len() - 1 {
// Regular character
buffer[buf_idx] = byte;
buf_idx += 1;
uart.write_byte(byte);
}
}
}
/// Simple parser for u8 from ASCII bytes
fn parse_u8(bytes: &[u8]) -> Result<u8, ()> {
let mut result = 0u8;
for &b in bytes {
if b.is_ascii_digit() {
result = result.checked_mul(10).ok_or(())?;
result = result.checked_add(b - b'0').ok_or(())?;
} else {
return Err(());
}
}
Ok(result)
}
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