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S32K312 IIC DMA slave mode maximum receiving length can only be 8 bytes

Hi all

 I am using the DMA function of the IIC slave, but the maximum length that IIC can receive at once is only 8 bytes. Data exceeding 8 bytes cannot be retrieved from the buffer. I have uploaded the project, can you help me identify the problem.

Thanks

Re: S32K312 IIC DMA slave mode maximum receiving length can only be 8 bytes

Thank you for your help. Although there is a problem with this routine, it can be used to compare the errors in my current project. I have identified the cause

Re: S32K312 IIC DMA slave mode maximum receiving length can only be 8 bytes

Hi @Reyna_pan45 

I have observed that the project is based on the application provided in Example S32K312 I2C Transmit & Receive Using DMA DS3.5 RTD300. Just to confirm, if no modifications are made to the project, presents the same behavior?

Re: S32K312 IIC DMA slave mode maximum receiving length can only be 8 bytes

As you said ：The number of bytes that can be transmitted per transfer is not restricted.

The received data length I set is 18 bytes ，Why can't I receive data exceeding 8 bytes？

Re: S32K312 IIC DMA slave mode maximum receiving length can only be 8 bytes

Hi @Reyna_pan45 

The I2C bus specification defines that each byte transmitted on the SDA line must be 8 bits long. The number of bytes that can be transmitted per transfer is not restricted.

While the hardware itself does not impose a limit on the read transfer size, it requires the software to queue multiple read commands for larger transfers. Currently, the driver can receive between 1 and 256 bytes of data, and it can also be configured to discard received data instead of storing it in the receive FIFO.

BR, VaneB