S32K311 NACK occurs in I2C communication by FlexIO

[MickMick]

Hi!

We use FlexIO for I2C communication with peripheral IC and have a problem.

FXIO_D0 is used as SCL and FXIO_D1 is used as SDA.

Sometimes, NACK is detected in the transmit event handler function in RTD below, around line 2268.

When NACK occurs, the local variable values and SMOD status are below.

Our questions are:
1. What are the possible causes of NACK?
2. How can we take steps to ensure that NACK does not occur?

Please instruct it.

Thank you!

[MickMick]

I am very sorry for the delay in replying.
I have checked the past information about the problem when FlexIO is used.
In the end, we implemented the I2C communication process in the direction of communicating by controlling GPIO with software instead of using FlexIO, and communication no longer fails.
Thank you very much for your help.

[danielmartynek · Accepted solution]

Hi @MickMick,

Can you please scope the bus? Is there a NACK on the bus?

There are some limitations in comparison to the dedicated LPSPI.

Have a look at this thread:

https://community.nxp.com/t5/S32K/I2C-through-FlexIO-doesn-t-work-right/td-p/907888

Regards,

Daniel