Posted on December 22, 2016 at 18:08Recently 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
