[Solved] How to properly stop/cancel a (SPI) DMA transfer when CRC is enabled?

[caco3]

Posted on October 07, 2015 at 11:45

I have a SPI slave (RX only) and need to use it with CRC check enabled (STM32F4, 8bit CRC generator of SPI unit).

To process the high amount of data, I use a P2M DMA. What is the correct way to stop/cancel a DMA transfer, before it is completed? Currently, I do it in this way:

void
init(
void
){
HAL_SPI_Receive_DMA(&hspi1, SPI_RX_Buffer, 10); 
//start DMA
}
void
HAL_SPI_RxCpltCallback(SPI_HandleTypeDef *hspi){
HAL_SPI_Receive_DMA(&hspi1, SPI_RX_Buffer, 10); 
//restart DMA
}
void
BUTTON_PRESS(
void
){
HAL_DMA_Abort(&hdma_spi1_rx); 
// Aborting a (possibly incomplete) DMA transfer
HAL_SPI_Receive_DMA(&hspi1, SPI_RX_Buffer, 15); 
//restart DMA with different length
}

This works fine, but only, if the CRC check is disabled!

//..
hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLED;
HAL_SPI_Init(&hspi1);
//..

If I enable the CRC check:

//..
hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_ENABLED;
hspi1.Init.CRCPolynomial = 0x10;
HAL_SPI_Init(&hspi1);
//..

it hangs in the function

HAL_DMA_Abort();

Specifically on the line

__HAL_DMA_DISABLE(hdma);

which is a macro for

hdma->Instance->CR &= ~DMA_SxCR_EN

So my question in summary: How do I properly stop/cancel a SPI RX DMA transfer, when the CRC generator is enabled?

[caco3]

Posted on October 12, 2015 at 14:59

I asked the ST Support to look into this.

They very quickly replied and told me this:

There is a bug in the library. The DMA stop triggers the DMA interrupt and the driver expects data. I created some workaround that should work. Instead of just calling DMA stop you must call:

__disable_irq(); 
/* might not be necessary */

 hspi1.hdmarx->XferCpltCallback = NULL;
 HAL_SPI_DMAStop(&hspi1);
 __enable_irq(); 
/* might not be necessary */

Disable interrupt might not be necessary. This fix works for me as expected! Note: I am currently using the latest versions:

STM32Cube_FW_F4_V1.8.0 including STM32F4xx_HAL_Driver (V 1.4.0) and CMSIS (V 2.4).

Disabling/enabling the irqs was not necessacy for me.