Bug in stm32f3xx_hal_i2c.c

[fal.sch]

CubeIDE version 1.4.1

STM32Cube FW_F3 V1.11.0

I had the problem, that my I2C communication (alternating rx/tx on slave) works on the first rx/tx cycle but fails on the second tx.

The transmission skips the first byte and thus sending n-1 bytes. I found out that, after calling I2C_ITSlaveCplt() on line 4744, the execution of the function continues and decrements the XferCount on line 4802.

I fixed the driver as follows (original line 4740-4745):

/* Check if STOPF is set */
  if ((I2C_CHECK_FLAG(tmpITFlags, I2C_FLAG_STOPF) != RESET) && (I2C_CHECK_IT_SOURCE(ITSources, I2C_IT_STOPI) != RESET))
  {
    /* Call I2C Slave complete process */
    I2C_ITSlaveCplt(hi2c, tmpITFlags);
  }

/* Check if STOPF is set */
  if ((I2C_CHECK_FLAG(tmpITFlags, I2C_FLAG_STOPF) != RESET) && (I2C_CHECK_IT_SOURCE(ITSources, I2C_IT_STOPI) != RESET))
  {
    /* Call I2C Slave complete process */
    I2C_ITSlaveCplt(hi2c, tmpITFlags);
    
    // BEGIN BUG FIX
    __HAL_UNLOCK(hi2c);
 
    return HAL_OK;
    // END BUG FIX
  }

[fal.sch]

Alternatively the following if-statement could be changed to an else-if-statement which is similar to the previous working driver version.

[Amel NASRI]

Hi @fal.sch​ ,

This issue is reported to our development team for farther check and analysis in order to apply the adequate solution.

Thanks for highlighting it.

-Amel