Using UART different methods

RE: Using UART different methods

ovrebekk — Thu, 08 Sep 2022 10:54:37 GMT

Good to hear that you found a good solution. The best of luck with your project 🙂

Best regards
Torbjørn

RE: Using UART different methods

baconcheese13 — Tue, 06 Sep 2022 05:45:40 GMT

Thanks for the direction! I ended up using async RX with a message queue, very similar to the implementation in the echo_bot example which fit my needs perfectly

// serial.c
void serial_cb(const struct device* dev, void* user_data)
{
    uint8_t c;
    while (uart_irq_rx_ready(uart1_dev)) {
        uart_fifo_read(uart1_dev, &c, 1);
        bool is_break = c == '\n' || c == '\r';

        if (is_break && rx_buf_pos > 0) {
            rx_buf[rx_buf_pos] = '\0';
            k_msgq_put(&uart_msgq, &rx_buf, K_NO_WAIT);
            rx_buf_pos = 0;
        } else if (!is_break && rx_buf_pos < (sizeof(rx_buf) - 1)) {
            rx_buf[rx_buf_pos++] = c;
        }
    }
}

// main.c
while (1) {
	// will be a full line received from the message queue
	while (k_msgq_get(&uart_msgq, &tx_buf, K_NO_WAIT) == 0) {
		print_uart("Echo: ");
		print_uart(tx_buf); 
		print_uart("\r\n");
	}
	// will be a single character from user to send to modem
	while (uart_poll_in(uart0_dev, &c) == 0) { 
		printk("%c", c);
		uart_poll_out(uart1_dev, c);
	}

}

RE: Using UART different methods

ovrebekk — Mon, 05 Sep 2022 09:13:35 GMT

It is possible to copy the received data into a message queue or buffer. You just need to keep in mind that the offset value is for the source buffer in the UART driver, not for your own buffer.

There is an unofficial sample available here showing how you can handle UART async with non dynamic memory management. In particular take a look at the handling of the RX callback here.

Best regards
Torbjørn