DMA -> MDMA chaining stm32h7

[MonsieurShann]

Hello everyone,

Context : 

I am having troubles chaining the DMA1 and MDMA of the stm32h755, more precisely, I am looking for the following data flow when reading data from SPI, the SPI being regularly triggered  : 

SPI -> DMA1 Channel3 -> SRAM -> MDMA Channel 3 -> DTCM.

I transfer 4 halfwords between my SPI and my SRAM. I also want to move 4 halfwords between my SRAM and my DTCM thanks to the MDMA.

The connection between the DMA1 Channel 3 and the MDMA Channel 3 being the DMA1 Channel Transfer complete request.

Problem : 

I have no problem moving data from SPI to SRAM using DMA1 Channel 3 every time I read something on my SPI.
However my MDMA is only working on the first transfer, then he's not transfering no more, even if my DMA1 Channel 3 transfer complete has triggered. I could not figure why..

Code : 

hmdma_mdma_channel3_dma1_stream3_tc_0.Instance = MDMA_Channel3;
hmdma_mdma_channel3_dma1_stream3_tc_0.Init.Request = MDMA_REQUEST_DMA1_Stream3_TC; // Requête déclenchée par DMA1_Stream3_TC
hmdma_mdma_channel3_dma1_stream3_tc_0.Init.TransferTriggerMode = MDMA_BUFFER_TRANSFER;
hmdma_mdma_channel3_dma1_stream3_tc_0.Init.Priority = MDMA_PRIORITY_LOW;
hmdma_mdma_channel3_dma1_stream3_tc_0.Init.Endianness = MDMA_LITTLE_ENDIANNESS_PRESERVE;

hmdma_mdma_channel3_dma1_stream3_tc_0.Init.SourceInc = MDMA_SRC_INC_HALFWORD;      // Incrémentation de la source
hmdma_mdma_channel3_dma1_stream3_tc_0.Init.DestinationInc = MDMA_DEST_INC_HALFWORD; // Incrémentation de la destination

hmdma_mdma_channel3_dma1_stream3_tc_0.Init.SourceDataSize = MDMA_SRC_DATASIZE_HALFWORD;
hmdma_mdma_channel3_dma1_stream3_tc_0.Init.DestDataSize = MDMA_DEST_DATASIZE_HALFWORD;

hmdma_mdma_channel3_dma1_stream3_tc_0.Init.BufferTransferLength = 4; // Transfert de 4 HALFWORDS

hmdma_mdma_channel3_dma1_stream3_tc_0.Init.SourceBurst = MDMA_SOURCE_BURST_4BEATS; // Burst de 4 HALFWORDS
hmdma_mdma_channel3_dma1_stream3_tc_0.Init.DestBurst = MDMA_DEST_BURST_4BEATS;     // Burst de 4 HALFWORDS

hmdma_mdma_channel3_dma1_stream3_tc_0.Init.SourceBlockAddressOffset = 0;
hmdma_mdma_channel3_dma1_stream3_tc_0.Init.DestBlockAddressOffset = 0;

And :

HAL_MDMA_Start_IT(&hmdma_mdma_channel3_dma1_stream3_tc_0,
                      (uint32_t)adc_burst_sram, 
                      (uint32_t)adc_burst_dtcm,
                      sizeof(adc_burst_sram), 
                      1)

If someone has an idea :)

Regards,

[Saket_Om]

Hello @MonsieurShann 

Please refer to the example Projects/NUCLEO-H7A3ZI-Q/Examples/MDMA/MDMA_LinkedList to set your MDMA transfer.