Bug in HAL_I2C_Master_Transmit()

[toby2]

Posted on December 22, 2016 at 18:08

Recently I wasted a frustrating few days finding out why my code was unstable. Turned out to be what I believe is a bug in HAL_I2C_Master_Transmit() so I thought I should post here in case it catches anyone else out. The relevant bit of code.....

while(hi2c->XferSize > 0U)

{

   /* Wait until TXE flag is set */

   if(I2C_WaitOnTXEFlagUntilTimeout(hi2c, Timeout, tickstart) != HAL_OK)

   {

      if(hi2c->ErrorCode == HAL_I2C_ERROR_AF)

      {

         /* Generate Stop */

         hi2c->Instance->CR1 |= I2C_CR1_STOP;

         return HAL_ERROR;

      }

      else

      {

         return HAL_TIMEOUT;

      }

   }

   /* Write data to DR */

   hi2c->Instance->DR = (*hi2c->pBuffPtr++);

   hi2c->XferCount--;

   hi2c->XferSize--;

   if((__HAL_I2C_GET_FLAG(hi2c, I2C_FLAG_BTF) == SET) && (Size != 0U))

   {

      /* Write data to DR */

      hi2c->Instance->DR = (*hi2c->pBuffPtr++);

      hi2c->XferCount--;

      hi2c->XferSize--;

   }

   .........

}

I think the line

if((__HAL_I2C_GET_FLAG(hi2c, I2C_FLAG_BTF) == SET) && (Size != 0U))

should actually read

if((__HAL_I2C_GET_FLAG(hi2c, I2C_FLAG_BTF) == SET) && (hi2c->xferSize != 0U))

As it is, any time the xferSize is 1 at the top of the loop and the BTF flag is set it decrements xferSize past zero and it does not exit the loop correctly.

♯♯

#bug #hal #i2c

[Nesrine M_O]

Posted on December 22, 2016 at 18:34

Hi

Mack.Toby

‌,

You are right. Thank you for bringing this issue to our attention and sorry for the inconvenience it may bring.

It is noted and will be fixed soon.

-Nesrine-

Ifmy suggestanswers your question, please mark it as correct.

[j o]

Posted on April 12, 2018 at 20:39

I don't know what system Toby is referring to, but this bug has yet to be fixed in the L1 series of HAL drivers.  I suggest this code be reviewed in all versions of the STM32.

Having a central git repository, with a common code base, rather than separate for each processor, where all these issues can be cataloged would be awesome.