SPI Bursts of CM4 on imx7

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SPI Bursts of CM4 on imx7

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miguel13366
Contributor I

Hey,

I am using ecspi on the cortex M4 core of the imx7. I need to make the communication faster.
At the moment the spi sends a burst of 4bytes. Between every burst I have a break of 2.5µs. Is there an opinion to make this faster? Or any other option to speed up the communication?
The software is based on the freertos example ecspi_polling_master.

best regards

Michael

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CarlosCasillas
NXP Employee
NXP Employee

Hi Michael,

You could refer to Chapter 5 “Enhanced Configurable Serial Peripheral Interface (eCSPI)” of “FreeRTOS BSP i.MX 7Dual API Reference Manual” document to verify the features of the eCSPI driver included on the FreeRTOS BSP, and the available APIs, including the usage of DMA.

Hope this will be useful for you.
Best regards!
/Carlos
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miguel13366
Contributor I

Hey CarlosCasillas,

I had a closer look on my problem. It seems, the time between the bursts, wont getting shorter, so I increased my clock rate and got new problems.

With the 48MHz CLK, the controller misses the first bit of the frame. I disabled the hysteresis, but the problem still occurs. 2019-12-05 08_25_03-scope_9.png - IrfanView.png

The data is be captured on the falling edge, so I should receive 0b0110xxxx, but I am receiving 0b00110xxx. Physically the correct data is transmitted, but not written into my receive buffer.

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JanChiang
Contributor I
 
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