What Is the Best Way to Handle I2C Communication Errors on STM32?

[cedrick]

When using I2C peripherals with an STM32, occasional NACKs or communication timeouts can be difficult to diagnose.

How do you usually approach debugging these issues? Do you start by checking the bus signals with a logic analyser, reviewing the timing configuration, or inspecting the firmware error handling?

I'd be interested in hearing which debugging techniques have been most useful in practice.

[Andrew Neil]

You always need to start by checking the hardware - it’s pointless to dive into the software before you know that it’s a software problem!

 

Do you start by checking the bus signals with a logic analyser

 Before using a LA, you need to check with an oscilloscope that the signals are clean, at the right levels, etc.

Without first checking those “analogue” issues, a LA can give misleading results.

 

When your problems are “occasional”, that most likely indicates a hardware issue - such as noise, poor connections, marginal pullups, etc.

 

In software, always check the return codes from driver functions, and act on them.

If you’re writing your own drivers, be sure that they detect fault conditions, and return useful error codes. Test this!

 

Again, none of this is specific to STM32.

 

Some previous threads on recovering from I2C failures:

 

[cedrick]

Thanks, Andrew. That’s a useful reminder to verify the electrical signals with an oscilloscope before relying on logic-analyser results. I’ll also keep the importance of checking driver return codes and handling errors properly in mind. Appreciate the detailed explanation and linked references!

[Peter BENSCH]

Please let us know exactly which STM32 you are currently using, and what I2C clock frequency and peripheral setup are being used.

Regards
/Peter

[cedrick]

Thanks, Peter. I haven’t specified a particular STM32 or peripheral configuration, as I was interested in general debugging practices rather than troubleshooting a specific setup. I appreciate the clarification.

[Ozone]

And I might add, this includes reading and understanding the datasheet of the I2C slave device.
A NACK from a slave is not necessarily a hardware problem or software isse, but can result from incorrect expectations.

This especially applies to reused ‘foreign’ example code that uses only a fraction of the slave’s features.
For example, many serial EEPROM or Flash devices with I2C interface from different manufacturers have mostly identical features and specifications, but occasionally differ in subtle ways.

[Andrew Neil]

(deleted response to @cedric the AI bot)

[David Littell]

This type of thread is beginning to reek of yet-another AI-rooted waste of everyone’s time.

[Peter BENSCH]

Correct, that’s the reason why it is closed now.