Asset Tracker v2, using I2C instead of LEDs with UI module

[zachary_z]

I have read some of the Asset Tracker documentation and noticed there is a nice implementation for operating LEDs in the UI module. This seems straightforward for GPIO control, but what about using an I2C device instead? We have our own LED driver that uses I2C and would like to use this instead of LEDs in GPIO pins. Is there a simple way to program this or would it be much more time-consuming?

[Hakon]

Hello,

if you have a LED driver that uses I2C then of course you need to use I2C to communicate with it and not GPIO.

Is there a simple way to program this or would it be much more time-consuming?

I don't know. What type of LED driver is it? Do you have a data sheet for it? I can't imagine it being a hard task.

[zachary_z]

I'm currently having difficulty figuring out what functions actually control the LEDs, for example the actual functions that drive the GPIO pins. My idea was to just modify these. Any tips on where to start?

[Hakon]

zachary_z said:

For example, I cannot find any instance of gpio_pin_configure_dt being called in Asset Tracker.

That's most probably because Asset Tracker is using a more high level API to access the LEDs. This sample uses a more low level approach and accesses the LEDs directly.

[zachary_z]

Do you have any recommendations on where to start modifying the code to either bypass the high level APIs or on how to make the I2C compatible with this API?

[JONATHAN LL]

Håkon will be back next week, pardon the delay, summer vacation in Norway. 

Regards,
Jonathan

[Hakon]

zachary_z said:

Do you have any recommendations on where to start modifying the code to either bypass the high level APIs

If you want to "bypass the high level API" you can just set the GPIO pins directly, which is what is done in the sample I provided. But you said that the LED driver uses I2C to access the LEDs, which means you probably need to write your own functions for communicating with the LEDs.

[zachary_z]

I am still lost on this. I was looking into other ways to do this and read about the Application Event Manager. To rephrase my problem, my goal is to perform an action on an I2C device depending on what the chip is doing within the Asset Tracker program. Would creating an event or module etc. that would execute this be a more 'correct' way?

[Hakon]

zachary_z said:

Would creating an event or module etc. that would execute this be a more 'correct' way?

Creating a module would probably be the way to go then. Then in the event handler of that module you would perform the actions on the I2C based on the event received. You can take a look at this for reference https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/libraries/others/app_event_manager.html#code_example .