STM32L476, HAL library SPI3 write lead to hard reset

[Riscy24]

I have the below code, which is supposed to update DAC with sinewave via SPI3 bus. It was configured and working fine via discrete command, but when I used timer7 to generate an event and update DAC16 via SPI3 via the HAL library, it went to hard fault. I have never seen this before. What caused the hard fault to occur?

I use Nucleo STM32L476 and updated IDE and drivers.

Note I have not included the /CS code (yet) because I was trying to figure out what caused the hard fault. I use optimization -Ofast.

#define DAC16_CENTER (32768)
bool FID_DAC16_Timer7_Sinewave_Event(void)
{
volatile static uint16_t DACSine_Pointer=0;

//--------------------------------------------------
zFID_Obj *zFIDObj = (zFID_Obj *)zFIDHandle; // assign the object (local) utobj->
//--------------------------------------------------
uint16_t dacdata = FID_SineWaveTable[DACSine_Pointer];
if (DACSine_Pointer >= FID_SinewaveSise)
{
DACSine_Pointer= 0;
}
else
{
DACSine_Pointer++;
}
//------------------------------- Process amplitude adjustment while keeping center center.

int32_t centered = (int32_t)dacdata - DAC16_CENTER;
centered = centered / zFIDObj->DACSine_Amp;
dacdata = (uint16_t)(centered + DAC16_CENTER);
//------------------------------- Write data to SPI
uint8_t data[] = { dacdata & 0xFF, dacdata >> 8 }; //flipped for proper ordering of MSD.
HAL_SPI_Transmit(&hspi3, data, 1, HAL_MAX_DELAY); // Hard fault crashed event.

//FID_SPI_WriteData16Simple(FID_CS1_DAC16A,dacdata);
return true;
}

[Riscy24]

I forgot to mention I use 16-bit SPI data, but the HAL SPI transmit and received are working fine when not running from Timer7. 

[Andrew Neil · Accepted solution]

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@Riscy24 wrote:

What caused the hard fault to occur?

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https://community.st.com/t5/community-guidelines/how-to-write-your-question-to-maximize-your-chances-to-find-a/tac-p/708193/highlight/true#M51

[Riscy24]

Thank for the link, very useful. It turned out it was divided by zero hard fault. Nothing to do with HAL library which is a relief. 

Lesson learnt and moving on!

R.