Cannot Receive Serial from Hardware when changing espressif32 core 6.10.0

PlatformIO Core
,
1

Hi, ESP32 xiao board cannot receive data over hardware serial when changing from
core espressif32 2025.3.30 to Esperssif 32 6.10.0.
I find out that espressif32 2025.3.30 is Tasmota Espressif 32
But when using espressif32 2025.3.30 version, esp32 can sends and receives data over UART normally. When I changed to version 6.10.0, it cannot receives anything. But the problem is espressif32 2025.3.30 cannot include WiFiClientSecure.h library which I need to use for MQTT client. Please hep
This is my platformio.ini

[env:seeed_xiao_esp32s3]
platform = espressif32
board = seeed_xiao_esp32s3
framework = arduino
build_flags = -DBOARD_HAS_PSRAM
	-DCORE_DEBUG_LEVEL=ARDUHAL_LOG_LEVEL_WARN
board_build.arduino.memory_type = qio_opi
board_build.f_flash = 80000000L
board_build.flash_mode = qio
monitor_speed = 115200
monitor_rts = 0
monitor_dtr = 0
board_build.filesystem = littlefs
lib_deps = 
	seeed-studio/Seeed_Arduino_SSCMA@^1.0.0
	bblanchon/ArduinoJson@^7.4.1
	hideakitai/ArduinoEigen@^0.3.2
	knolleary/PubSubClient@^2.8

And this is my code to config to communicate between ESP32Xiao module with other devices over serial

void startRemoteProxy(Proto through = PROTO_UART) {
    switch (through) {
    case PROTO_UART: {
#ifdef ESP32
        static HardwareSerial atSerial(0);
        atSerial.setRxBufferSize(128 * 1024);
        atSerial.begin(921600);
#else
    #define atSerial Serial1
        atSerial.setRxBufferSize(128 * 1024);
        atSerial.begin(921600);
#endif
        AI.begin(&atSerial, D3);
        delay(100);
        char* cmd_buf = (char*)malloc(CMD_BUFFER_SIZE);
        size_t cmd_size = 0;
        memset(cmd_buf, 0, CMD_BUFFER_SIZE);
        strcpy(cmd_buf, "AT+STAT?");
        cmd_size = strlen(cmd_buf);
        AI.write(CMD_PREFIX, strlen(CMD_PREFIX));
        AI.write(cmd_buf, cmd_size);
        free(cmd_buf);
        AI.write(CMD_SUFFIX, strlen(CMD_SUFFIX));
        break;
    }

Please support me. Thank you

2

The board manifest for the seeed_xiao_esp32s3 defines

  -DARDUINO_USB_CDC_ON_BOOT=1

Which means that every output to the Serial object is routed to the native USB port of the ESP32-S3 and not to the UART port.

You can either

  • change your code to use Serial0
    or
  • stay with Serial and change the setting in the platformio.ini:
build_unflags = 
  -DARDUINO_USB_CDC_ON_BOOT

The following settings should be removed from your platformio.ini as they are handled by the board manifest:

  -DBOARD_HAS_PSRAM
board_build.arduino.memory_type = qio_opi
board_build.f_flash = 80000000L
board_build.flash_mode = qio

Please ask yourself whether you really need these settings or whether they can be removed:

monitor_rts = 0
monitor_dtr = 0
-DCORE_DEBUG_LEVEL=ARDUHAL_LOG_LEVEL_WARN
1 Like
3

Hi, thank you for your reply
I still use the Serial.print() for debugging over the usb port on ESP32S3 Xiao module.
And I need 1 more Serial interface to communicate with other module (Grove AI Vision V2). That why I need to setup HardwareSerial.
The problem is: when using Tasmota ESP32 core, the 2 modules communicates fine. Only when changging to ESP32 6.10.0, it not work anymore.

4

If you use -DARDUINO_USB_CDC_ON_BOOT=1 (which is the default for the seeed_xaio_esp32s3), Serial will print to USB and Serial0 print to UART:

Serial → USB
Serial0 → UART

Sorry, I don’t know the modifications of the Tasmota fork. But I know there are alot.

1 Like
5

And I compile and upload code via arduino IDE, it still works fine.
Do you any changes related to Hardware serial on Espersiff32 6.10.0?

6

Which Espressif32 Arduino version do you have installed in your ArduinoIDE?

platform = espressif32 @ 6.10.0 is Espressif32 Arduino 2.0.17.

If you want to use Espressif32 Arduino 3.x you have to use the pioarduino fork:

platform = https://github.com/pioarduino/platform-espressif32/releases/download/54.03.20/platform-espressif32.zip → Espressif32 Arduino 3.2.0

1 Like
7

I use Arduino IDE 2. Espressiff32 version is 3.0.7. Maybe this is the reason.

8

3.0.7 is

platform = https://github.com/pioarduino/platform-espressif32/releases/download/51.03.07/platform-espressif32.zip

I have listed the available versions here.

1 Like
9

thank you very much for your enthusiastic support.
I’m really appreciate your kindness and knowledge. I will try and inform back to you the result

1 Like
10

thanks, it worked.
Thank for your help