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i.mx ecspi gap within spi burst tx packet

Question asked by Alex Hinton on Jun 2, 2020
Latest reply on Jun 11, 2020 by Yuri Muhin

Hi,

I'm using the i.MX6ULL processor, and I've setup the ecspi 1 in burst transmission mode, with 32 bits-per-word and a burst length of 128 words. However, I'm only needing to send 240 bytes in a single burst transmission. The data output is clocked at 3.45 MHz.

 

The issue I'm seeing in the data packet is an occasional (although seemingly periodic) gap in the transmission. This gap will always be around 1usec in length, and its a delay that is present on the MOSI data and spi clock (indicating the data didn't get changed or corrupted).  A screen-capture of this delay is provided.

 

My 240 byte burst transmission works as intended for a majority of the time, but perhaps ~1/4 of the time this delay will occur within the packet messing up the timing. The DMA for the SPI is being setup and used here. Is it correct for me to think my SPI settings aren't the issue since it works without interruption a portion of the time? What would be causing this; is it possible for something else to be interrupting the SPI even with the DMA handling the buffer transfer?

 

Thanks.

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