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rlegault
Associate
January 16, 2024
Solved

3 SPI busses does not parallelize data access

  • January 16, 2024
  • 1 reply
  • 1112 views

STM32H743
We have 4 SPI busses running at 12.5MHz but the SPI clocks are sequentially. SPI 1 and 2 are using DMA Channel 1 while SPI 3 and 4 are using DMA Channel 2. We would like them to run in parallel.
Can they run in parallel.

The code uses HAL_SPI_TransmitReceive_DMA() for each of the calls to the spi to Tx and Rx.The picture below definitely shows serialization of the accesses. Each access is 32 bytes.

rlegault_0-1705436036380.png

The picture above shows the clocks of 3 of the spi busses and it is quite evident that the SPI busses are not running in parallel.

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Best answer by rlegault

The SPI accesses were ending before the next one could be setup decreasing the clock frequency shows them running in parallel.

3spi_in_parallel.png

1 reply

rlegault
rlegaultAuthorBest answer
Associate
January 16, 2024

The SPI accesses were ending before the next one could be setup decreasing the clock frequency shows them running in parallel.

3spi_in_parallel.png