Read data from STM32 using UART ESP32 micropython \x00 error?

Question

I am using a LOLIN32 lite (ESP32) to read data sent from a STM32F103 (black pill). The ESP32 is using micropython and the STM32 is programmed using CubeMX + Truestudio.

When calling the uart.read() or uart.readline() in micropython I get the data sent by the STM32 but it has appended a \x00 value at the beginning.

From Tera terminal I get: b’\x00test message\n’

CubeMX:

Code used in the STM32 (I am using the HAL library, the rest of the code is too long to post).

uint8_t buff_uart[] = "test\t a long message\n";

while (1){
   HAL_UART_Transmit(&huart1,buff_uart,sizeof(buff_uart),1);
   HAL_Delay(1000);
}

Code in micropython:

uart = UART(2, 115200)
uart.init(115200, bits=8, parity=None, stop=1, timeout=2000)

while True:
   uart.readline() 

If I connect the serial line from the STM32 to a serial USB I can see the right data in Tera terminal (without \x00). Can it be that micropython add a delimiter?

or is this an error? What I am missing here?

Answer 1

1. write uart transmit code for and load it to on STM32 board
2. write a UART code in micropython launguage for esp32
3. connect their Rx and Tx and run esp32 code