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YScha.1
YScha.1
Associate
January 23, 2020
Question

The I2c is not working when I enter in debug mode from the STM32CubeIDE. Do you know why?

  • January 23, 2020
  • 1 reply
  • 1426 views

I am reading a accelerometer and gyros of the IKS01A2 board with the provided STM library (lsm6dsl) on the Nucleo STM32F446Re. I modified the I2c to be able to used with the board using CubeMx.

Now the i2C communication only works when I plug the Nucleo to the USB. When I try to start the board in Debug mode (in the STMCubeIDE) the I2c never strarts. It only starts again when I unplug the board from USB and plug it in again. Also pressing the reset button in debug mode does not help to start the I2C. I was searching now for a long time but I did not find any post which was describing the same problem. Do you have any iday what my problem could be?

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1 reply

YScha.1
YScha.1Author
Associate
February 5, 2020

Apparently, the problem was that SDA was staying LOW because the data transmission was not finished during the reset which occurs when entering the debug mode. I solved the problem by checking at start-up if the SDA pin is LOW.  If it is, I cycle the SCL Pin 9 times and check again if the SDA pin went HIGH.

Bus locking due to transmission abortion is a well-known I2C issue, that’s why I am wondering if there is no standard routine to solve this issue?

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