Sample zephyr adc not working

[Sahu]

Hi,

I am using nrf52833dk_nrf52820 to test adc sample in samples/boards/nrf/battery.

I have issues in building.  

.dts has no adc, so i added it in overlay as suggested in readme. 

.overlay has following.

/ {

    zephyr,user {

       io-channels = <&adc 4>;

    };

 };

 &adc {

    status = "okay";

};

I am seeing following error message

devicetree error: C:/Users/sxt0714/Documents/Workspace/Zephyr-examples/adc/test_battery/nrf52833dk_nrf52820.overlay:19 (column 2): parse error: undefined node label 'adc'
CMake Error at C:/ncs/v2.0.0/zephyr/cmake/modules/dts.cmake:213 (message):
gen_defines.py failed with return code: 1
Call Stack (most recent call first):
C:/ncs/v2.0.0/zephyr/cmake/modules/zephyr_default.cmake:121 (include)
C:/ncs/v2.0.0/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:51 (include)
C:/ncs/v2.0.0/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:81 (include_boilerplate)
CMakeLists.txt:5 (find_package)

if I dont use overlay, i am seeing following build issue.

[Sahu]

Hi sorry. 

Just noticed nrf52820 doesnt have adc. Can you direct me to a comparator example for the same.

[Naeem Maroof]

Hi Swathi,

Yes, we don't have an ADC on nrf52820.

Also, I don't have a specific example for your case. Nonetheless, You can use NRFX COMP drivers.

Regards,
Naeem

[Sahu]

Hi,

I used NRFX COMP drivers.

I have a doubt on comparator. On a single ended mode, is it compulsary to specify Vup thrershold and Vdown threshold?

For my application, I will be looking for Voltage to drop down below a particular V level to trigger interrupt. I dont need two V levels just need 1 lower threshold voltage and what is the best example to look into for software interrupt?

[Naeem Maroof]

Hi Swathi,

In a single-ended mode, we must configure TH that will use reference ladder (using VREF) to configure VUP and VDOWN.