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fix(uart): allow same pin for tx and rx in uart_set_pin

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Closes https://github.com/espressif/esp-idf/issues/14787
This commit is contained in:
Song Ruo Jing
2025-01-08 21:25:26 +08:00
parent cc42463d6b
commit eaf4b3f3e6
3 changed files with 57 additions and 18 deletions
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components/driver/uart/uart.c
+8 -5
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@@ -1,5 +1,5 @@
/*
* SPDX-FileCopyrightText: 2015-2024 Espressif Systems (Shanghai) CO LTD
* SPDX-FileCopyrightText: 2015-2025 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
@@ -623,18 +623,21 @@ esp_err_t uart_set_pin(uart_port_t uart_num, int tx_io_num, int rx_io_num, int r
ESP_RETURN_ON_FALSE((rts_io_num < 0 || (GPIO_IS_VALID_OUTPUT_GPIO(rts_io_num))), ESP_FAIL, UART_TAG, "rts_io_num error");
ESP_RETURN_ON_FALSE((cts_io_num < 0 || (GPIO_IS_VALID_GPIO(cts_io_num))), ESP_FAIL, UART_TAG, "cts_io_num error");
// Since an IO cannot route peripheral signals via IOMUX and GPIO matrix at the same time,
// if tx and rx share the same IO, both signals need to be route to IOs through GPIO matrix
bool tx_rx_same_io = (tx_io_num == rx_io_num);
/* In the following statements, if the io_num is negative, no need to configure anything. */
if (tx_io_num >= 0 && !uart_try_set_iomux_pin(uart_num, tx_io_num, SOC_UART_TX_PIN_IDX)) {
if (tx_io_num >= 0 && (tx_rx_same_io || !uart_try_set_iomux_pin(uart_num, tx_io_num, SOC_UART_TX_PIN_IDX))) {
gpio_hal_iomux_func_sel(GPIO_PIN_MUX_REG[tx_io_num], PIN_FUNC_GPIO);
esp_rom_gpio_connect_out_signal(tx_io_num, UART_PERIPH_SIGNAL(uart_num, SOC_UART_TX_PIN_IDX), 0, 0);
// output enable is set inside esp_rom_gpio_connect_out_signal func after the signal is connected
// (output enabled too early may cause unnecessary level change at the pad)
}
if (rx_io_num >= 0 && !uart_try_set_iomux_pin(uart_num, rx_io_num, SOC_UART_RX_PIN_IDX)) {
if (rx_io_num >= 0 && (tx_rx_same_io || !uart_try_set_iomux_pin(uart_num, rx_io_num, SOC_UART_RX_PIN_IDX))) {
gpio_hal_iomux_func_sel(GPIO_PIN_MUX_REG[rx_io_num], PIN_FUNC_GPIO);
gpio_set_pull_mode(rx_io_num, GPIO_PULLUP_ONLY); // This does not consider that RX signal can be read inverted by configuring the hardware (i.e. idle is at low level). However, it is only a weak pullup, the TX at the other end can always drive the line.
gpio_set_direction(rx_io_num, GPIO_MODE_INPUT);
gpio_ll_input_enable(&GPIO, rx_io_num);
esp_rom_gpio_connect_in_signal(rx_io_num, UART_PERIPH_SIGNAL(uart_num, SOC_UART_RX_PIN_IDX), 0);
}