nRF Connect SDK Fundamentals Lesson 6 Exercise 1: Question on the i2c node used in the example

[byt555]

Hello,

Step 5.2 of this part of the course has a code example which shows which i2c node to use to control the temperature sensor. In the case of the nRF54l15DK it is the &i2c22 node that is used. I also have a nRF52840DK and the code example uses &i2c0 for the sensor. I can see the &i2c0 node being defined in the dts file of the nRF52840DK (nrf52840dk_nrf52840.dts) but I cannot find the equivalent for the nRF54l15DK in any of the dts or dtsi files. The AI assistant says they can be found in the SOC level dtsi files but I still don't see them. How do you know which i2c controller / nodes can be used for that particular DK (especially for nRF54l15DK) ?

I believe I can also see the i2c controllers from the devicetree viewer but that requires a successful build first right? 

Thank you

[Kenneth]

Hello,

First of all make sure you understand that a lot of the peripherals share the same ID: 
https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/_tmp/nrf54l15/autodita/global.instantiation.html 

You can then for instance find that ID 198 is shared between SPIM20, SPIS20, TWIM20, TWIS20, UARTE20. Only one can be enabled. So if you enable TWIM20 (in the zephyr device tree that will be &i2c20), then you can't enable spi20 or uart20. You are kind of responsible to ensure that you meet this requirement (though the build system likely will throw an error if you don't uphold this).

I really recommend that you go through the nRF54L series express course that touch upon this and other things you should know when developing with the nRF54L-series, and also which considerations you should take when you decide on schematic and layout: https://academy.nordicsemi.com/courses/nrf54l-series-express-course/ The instantiation is different compared to the nRF52-series, the nRF54L-series have unique power domains that did not exist in the nRF52-series, so the numbering is different: https://academy.nordicsemi.com/courses/nrf54l-series-express-course/lessons/lesson-2-power-domains-event-system-and-gpio/topic/power-domains/ 

Hope that helps,
Kenneth

[byt555]

Hello Kenneth,

Should I stick with the nRF52 series instead of nRF54L if I'm just beginning to learn embedded programming?

Thank you

[runsiv]

Hi, Kenneth is out of office. In general I would recommend to stick with the nRF54L platform was it is around 10 years newer then the old 52 series. I don't see any reason to stick to the old platform. 

Regards

Runar