[release/2.x] fix(uart): Set back Pin signal polarity (#9952)

* fix(uart): Set back Pin signal polarity

Fixes a problem related to inverting signal polarity back to normal after a previous inversion.

This shall set the correct polarity in Serial.begin().

* fix(uart): Remove commentary

Removes a commentary with a question about the inversing polarity function.

* fix(uart): Update comment

Co-authored-by: Jan Procházka <[email protected]>

---------

Co-authored-by: Me No Dev <[email protected]>
Co-authored-by: Jan Procházka <[email protected]>

Author: 3 people

Diff for: cores/esp32/esp32-hal-uart.c

@@ -434,12 +434,16 @@ uart_t* uartBegin(uint8_t uart_nr, uint32_t baudrate, uint32_t config, int8_t rx
 
     if (retCode) retCode &= ESP_OK == uart_param_config(uart_nr, &uart_config);
 
-    // Is it right or the idea is to swap rx and tx pins? 
-    if (retCode && inverted) {
+    if (retCode) {
+      if (inverted) {
         // invert signal for both Rx and Tx
-        retCode &= ESP_OK == uart_set_line_inverse(uart_nr, UART_SIGNAL_TXD_INV | UART_SIGNAL_RXD_INV);    
+        retCode &= ESP_OK == uart_set_line_inverse(uart_nr, UART_SIGNAL_TXD_INV | UART_SIGNAL_RXD_INV);
+      } else {
+        // disable invert signal for both Rx and Tx
+        retCode &= ESP_OK == uart_set_line_inverse(uart_nr, UART_SIGNAL_INV_DISABLE);
+      }
     }
-    
+    // if all fine, set internal parameters
     if (retCode) {
         uart->_baudrate = baudrate;
         uart->_config = config;