K22 I2C eDMA Send 1 data byte

[Marc852]

Hi everyone,

I made a project using fsl_i2c_edma on a k22.

The project works except when i send 1 data byte through i2c, the callback never happened. 

I read later in the file fsl_i2c_edma.c : 

If transfer size is 1, use polling method

I don't understand why, can someone explain me ?

And, is it possible anyway to use the callback; stay in "standart" edma operation ?

MCUXpresso v11.0.0

SDK FRDM_K22F 2.6.0

Based on the example project  "i2c_edma_b2b_transfer_master"

Thanks in advance.

Marc.

[FelipeGarcia · Accepted solution]

Hello Marc,

This implementation is because for i2c send, you need to send 1 byte first to trigger the dma. In other words, because there must be an interrupt of complete 1-byte transfer to trigger the DMA, the address byte should be filled into I2Cx_D by the CPU itself.

Hope it helps!

Have a great day,
Felipe

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