feat(uart): testing P4 with RX1 pin fails on setting loopback

Author: SuGlider

Diff for: tests/validation/uart/uart.ino

@@ -53,7 +53,7 @@ public:
     : uart_num(num), serial(ser), peeked_char(-1), default_rx_pin(rx_pin), default_tx_pin(tx_pin), recv_msg("") {}
 
   void begin(unsigned long baudrate) {
-    serial.begin(baudrate);
+    serial.begin(baudrate, SERIAL_8N1, default_rx_pin, default_tx_pin);
     while (!serial) {
       delay(10);
     }
@@ -498,7 +498,8 @@ void setup() {
 
   uart_test_configs = {
 #if SOC_UART_HP_NUM >= 2 && defined(RX1) && defined(TX1)
-    new UARTTestConfig(1, Serial1, RX1, TX1),
+// inverting RX1<->TX1 because ESP32-P4 has a problem with loopback on RX1 :: GPIO11 + UART_RX SGINAL
+    new UARTTestConfig(1, Serial1, TX1, RX1),
 #endif
 #if SOC_UART_HP_NUM >= 3 && defined(RX2) && defined(TX2)
     new UARTTestConfig(2, Serial2, RX2, TX2),