RE: Dynamic I2C configuration

delossantos — Mon, 06 Mar 2023 12:13:03 GMT

Thanks for sharing useful information I will come back to your article to update with more new information.

RE: Dynamic I2C configuration

rdim — Thu, 09 Jun 2022 09:17:04 GMT

Hi Einar,

Thanks a lot for your suggestion! I will try to figure out if pin control could be used. I am little bit uncertain because of the following statement in the doc:

Note

Dynamic pin control should only be used on devices that have not been initialized. Changing pin configurations while a device is operating may lead to unexpected behavior. Since Zephyr does not support device de-initialization yet, this functionality should only be used during early boot stages.

As we would need to reset pins during on the fly, I would need to find a proper de-initialization function that is not static 🙂

And yes, i2c_configure() does change bitrate for me without re-initialization of the device. I was lucky that this function is only changing interface speed (and allowing 10 bits operations). Note, that the proper way to use it would be to a) get current configuration [that is not possible :\] b) modify it accordingly, and c) set it back using i2c_configure(). Its parameter dev_config is also "encrypted" as the doc only says that it is some bit-packed structure while in fact there are perfectly defined relevant macros in the codebase like for example

I2C_SPEED_SET(I2C_SPEED_FAST)

So I managed to change bitrate on the fly although I had to explore the SDK source for that 🙂

RE: Dynamic I2C configuration

Einarh — Wed, 08 Jun 2022 15:29:21 GMT

Hello!

I believe what you're looking for is Zephyr's Pin Control API.

At least for the changing pins part. Are you able to change bus speed at runtime using i2c_configure()?

Best regards,

Einar