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’


UART configuration 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){

Code in micropython:

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

while True:

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?

  • 2
    Have you checked it's not the other end sending it that way? – hardillb Oct 7 '18 at 14:29
  • Add your code of the STM32 to the question please. – Bence Kaulics Oct 7 '18 at 14:54
  • I added the code and clarified the post a bit better :) – Gabriel Oct 7 '18 at 16:55

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