Function uart_bitbang_tx_byte

src/drivers/uart/util.c:48–72

Helper function to allow bitbanging an 8n1 UART. */

/* Helper function to allow bitbanging an 8n1 UART. */
void uart_bitbang_tx_byte(unsigned char data, void (*set_tx)(int line_state))
{
	const int baud_rate = get_uart_baudrate();
	int i;
	struct stopwatch sw;
	stopwatch_init(&sw);

	/* Send start bit */
	set_tx(0);
	while (stopwatch_duration_usecs(&sw) < MHz / baud_rate)
		stopwatch_tick(&sw);

	/* 'i' counts the total bits sent at the end of the loop */
	for (i = 2; i < 10; i++) {
		set_tx(data & 1);
		data >>= 1;
		while (stopwatch_duration_usecs(&sw) < i * MHz / baud_rate)
			stopwatch_tick(&sw);
	}

	/* Send stop bit */
	set_tx(1);
	while (stopwatch_duration_usecs(&sw) < i * MHz / baud_rate)
		stopwatch_tick(&sw);
}