ESP32-P4：UART irDA mode don't work

[RadioDisney]

Board

ESP32-P4，M5Stack Tab5

Device Description

M5Stack Tab5 GPIO Pin，oscilloscope test

Hardware Configuration

#define IR_RX_R_PIN 46
#define IR_TX_R_PIN 44

Version

v3.3.0

Type

Bug

IDE Name

VSCode

Operating System

macOS 15.5

Flash frequency

40MHz

PSRAM enabled

yes

Upload speed

1152000

Description

https://github.com/pioarduino/platform-espressif32/releases/download/55.03.30-2/platform-espressif32.zip

#define IR_RX_R_PIN 46
#define IR_TX_R_PIN 44

Serial.begin(115200, SERIAL_8E1, IR_RX_R_PIN, IR_TX_R_PIN);
Serial.setMode(UART_MODE_IRDA); 

Serial.write(0xAA);

The IR_TX_R_PIN don't output anywave.

Sketch

don't crash

Debug Message

don't any message about the issue.

Other Steps to Reproduce

No response

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[lbernstone]

You need to set the LDO4 pins to 3V3 before using them.
https://github.com/espressif/arduino-esp32/pull/12079/changes

[SuGlider]

@RadioDisney - Please try this code for UART IrDA on UART1.

Further information on the ESP32-P4 TRM:
esp32-p4_technical_reference_manual_en.pdf

#include "soc/uart_struct.h"
#define IR_RX_R_PIN 16
#define IR_TX_R_PIN 17

void setup() {

  Serial1.setPins(IR_RX_R_PIN, IR_TX_R_PIN);  // ESP32-P4 TAB5 TX = 17
  Serial1.begin(115200);

  Serial1.setMode(UART_MODE_IRDA);

  // enables IRDA TX  // ESP32-P4
  UART1.conf0_sync.irda_tx_en = 1;
  // P4 needs UART Update
  UART1.reg_update.reg_update = 1;
  while (UART1.reg_update.reg_update);
}

void loop() {
  // sends binary 1010 1010 -- UART and IrDA send StartBit | LSB ... MSB | StopBit 
  Serial1.write(0xAA);  // 8N1 UART Frame = 0010101011 
  Serial1.flush();      // wait for TX Completed
  delay(1);
}

---

[SuGlider]

@RadioDisney - Please let me know if this issue can be closed.