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I2C problem using DMA on K66

Question asked by Emanuele Marraccini on Jul 22, 2019
Latest reply on Jul 30, 2019 by Felipe García

Dear All,

I'm using Kinetis K66 processor (MK66FN2M0VMD18) on a custom board and I'm having some troubles when I'm using DMA for I2C and SPI peripherals.

I'm using the following configuration:

- I2C0 peripheral on DMA channels 0 and 1;

- SPI0 peripheral on DMA channels 4 and 5.


When the SPI DMA channels are used it seems that I2C DMA channels stop wornking correctly. Notice that I2C DMA channels work fine until the SPI starts.


I've done a lot of tests and it seems that the problem is the DMA configuration or something like that.


If I switch DMA channel configuration priority like this the problem disappears but I don't know why:

- I2C0 peripheral on DMA channels 11 and 12;

- SPI0 peripheral on DMA channels 4 and 5.


Have you ever had a similar behavior? Could You explain the reason for the resolution of the issue when I change the priprity orde? Is this the correct way to operate or not?


Thank You for Your support, I will appreciate any answer or concerning experience about this issue.


Best regards