Using SAADC with Zigbee and NRF Connect SDK

[IanAber]

I am trying to figure out how to use the SAADC component of the nRF52840 to measure an analogue input and report it as an attribute in a Zigbee end device. I have, so far, failed to find an example that will compile using the latest development environment with the nRF Connect SDK 1.6.0. The library documentation does not appear to have anything that gives an overview of the SAADC component or any detail regarding how to incorporate this into a project. I enabled the component in the configuration (modules=>hal_nordic=>nrfx drivers=>Enable SAADC Driver) but I have no clue as to how to use it and I cannot find any examples of it. Can you point me to something that can get me started please?

[Simon]

Check out these Zephyr ADC samples:

• zephyr/samples/drivers/adc 
• zephyr/samples/boards/nrf/battery 

There is also an ADC sample in the NCS tutorial:  

• https://devzone.nordicsemi.com/nordic/nrf-connect-sdk-guides/b/getting-started/posts/nrf-connect-sdk-tutorial---part-2-ncs-v1-4-0#h185sjwm5882m1bcimiad82dnf4kcy0b 

Best regards,

Simon

[IanAber]

The tutorial say...

The tutorial supports these boards:

 → nRF9160 DK

 → nRF5340 DK

I am using the nRF25840 DK. What do I have to do to make the tutorial apply to that board, if it is possible.

The adc samle specifically states that is is NOT compatible with Nordic hardware and points to the battery example you listed. The battery example does not appear to be a Nordic project useable in Segger, unless I am missing something obvious, so I tried using the command line tools to build it with west. It built OK but when I tried to program it, west complains about a missing utility called nrfjprog which does not appear to be part of the NRF Connect SDK.

Is there some example that can be made to work with the nRF52840DK simply?

[Simon]

IanAber said:

The tutorial say...

The tutorial supports these boards:

 → nRF9160 DK

 → nRF5340 DK

I am using the nRF25840 DK. What do I have to do to make the tutorial apply to that board, if it is possible.

 I modified the ADC sample from the tutorial to support the nrf52840 dk, check it out here:

light_controller.zip

https://github.com/simon-iversen/sdk-nrf/tree/light_controller/samples/light_controller 

IanAber said:

The battery example does not appear to be a Nordic project useable in Segger, unless I am missing something obvious, so I tried using the command line tools to build it with west. It built OK but when I tried to program it, west complains about a missing utility called nrfjprog which does not appear to be part of the NRF Connect SDK.

Install the nRF Command Line Tools, then nrfjprog will get installed as well:

https://www.nordicsemi.com/Products/Development-tools/nRF-Command-Line-Tools/Download#infotabs

Best regards,

Simon

[IanAber]

Many thanks Simon. It looks like the main problem was that you had the adc_read call inside the interrupt service routing which is what was causing the errors I was seeing which didn't make any sense at first. Using a semaphore and putting the adc_read in the main thread got it working for me. I really appreciate the great support and speedy fixes. You are a gold mine.

[Simon]

I'm happy to help and glad you got it working :) 

An even better approach than using a semaphore is to use a work queue, like it's done here: 

https://github.com/too1/ncs-peripheral-uart-adc/blob/d575cdb9a2e0d7e5f0984a6a228bcb0d3a6f1a7c/src/main.c#L564

Best regards,

Simon