diff options
| -rw-r--r-- | ports/esp32/machine_uart.c | 19 |
1 files changed, 10 insertions, 9 deletions
diff --git a/ports/esp32/machine_uart.c b/ports/esp32/machine_uart.c index 982d9a7e2..661c07138 100644 --- a/ports/esp32/machine_uart.c +++ b/ports/esp32/machine_uart.c @@ -508,20 +508,21 @@ static bool mp_machine_uart_txdone(machine_uart_obj_t *self) { } static void mp_machine_uart_sendbreak(machine_uart_obj_t *self) { - // Save settings + // Calculate the length of the break, as 13 bits. uint32_t baudrate; check_esp_err(uart_get_baudrate(self->uart_num, &baudrate)); + uint32_t break_delay_us = 13000000 / baudrate; - // Synthesise the break condition by reducing the baud rate, - // and cater for the worst case of 5 data bits, no parity. - check_esp_err(uart_wait_tx_done(self->uart_num, pdMS_TO_TICKS(1000))); - check_esp_err(uart_set_baudrate(self->uart_num, baudrate * 6 / 15)); - char buf[1] = {0}; - uart_write_bytes(self->uart_num, buf, 1); + // Wait for any outstanding data to be transmitted. check_esp_err(uart_wait_tx_done(self->uart_num, pdMS_TO_TICKS(1000))); - // Restore original setting - check_esp_err(uart_set_baudrate(self->uart_num, baudrate)); + // Set the TX pin to output, pull it low, and wait for the break period. + mp_hal_pin_output(self->tx); + mp_hal_pin_write(self->tx, 0); + mp_hal_delay_us(break_delay_us); + + // Restore original UART pin settings. + check_esp_err(uart_set_pin(self->uart_num, self->tx, self->rx, self->rts, self->cts)); } // Configure the timer used for IRQ_RXIDLE |