NRF54L15-DK : ADC Threshold Event Configuration using LPCOMP and ANADETECT

[Pratik Panchal]

Hello Nordic Team,

I am currently working with the NRF54L15-DK. I have successfully configured the simple ADC on AIN4 (P1.11) and am able to read the raw sensor values.

Overlay : 

&adc {
	#address-cells = <1>;
	#size-cells = <0>;
	
	channel@4 {
		reg = <4>;
		zephyr,gain = "ADC_GAIN_1"; //"ADC_GAIN_1_4"
		zephyr,reference = "ADC_REF_INTERNAL";
		zephyr,acquisition-time = <ADC_ACQ_TIME_DEFAULT>;
		zephyr,input-positive = <NRF_SAADC_AIN4>; /* P1.11 */
		zephyr,resolution = <12>;
		//zephyr,oversampling = <2>;
	};
};

However, I would like to understand how to configure and set an ADC threshold using the ANADETECT feature. Specifically, I want to know how to detect when the ADC value crosses a defined threshold, either up , down or cross  and how to receive an event when this occurs. Additionally, I would like guidance on configuring the LPCOMP for this purpose.

Please provide the necessary prj.conf settings, .overlay configuration, and a sample example to help me implement this functionality.

Thanks & Regards,
Pratik Panchal

[Kenneth]

Hi,

I suggest to check out this answer:  Using the new LPCOMP driver in Zephyr 

Kenneth 

[Pratik Panchal]

Hello Kenneth 

Thank you for your response.

I reviewed the Nordic thread you shared and used the referenced code to configure and integrate a comparator into my application. I connected a potentiometer to the defined ADC pin for input variation.

However, I expected to receive specific up or down events based on the configured threshold up/down values.
I referred to the overlay file from the provided GitHub repository, but despite defining th_up and th_down values, the test_callback function does not increment the count on defined up or down threshold, but it only increments when we fully increase the potentiometer value to 4092 = 0.899V, and the event 
bool event = comparator_get_output(test_dev); Returns 1 on 0.899V.

Even I modified the value of th-up to 40, then also the event returns 1 only at 0.899V.

Here, my application overlay for the comparator :

&comp {
	compatible = "nordic,nrf-comp";
	main-mode = "SE";
	psel = "AIN4"; /* P1.11 */
	refsel = "VDD";
	sp-mode = "HIGH";
	th-up = <63>;
	th-down = <31>;//<59>;
	isource = "DISABLED";
	status = "okay";
};

 

Could you please provide a sample that demonstrates the detailed usage of the APIs for configuring up/down thresholds and handling the corresponding events?

Thanks & Regards,
Pratik Panchal

[Kenneth]

Hi,

Dont' have time to test the code, but make sure you understand the difference between COMP and LPCOMP:
https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/comp.html 
https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/lpcomp.html 

One can be used in sleep and wakeup the chip (lpcomp), the other is only active while the CPU is running (comp).

Kenneth

[Pratik Panchal]

Hi Kenneth,

Thanks for the response.

But I have already referred to your given links and online sources, but I won't get proper steps and information.

I want API docs and steps to configure (as per my requirement) the basic comparator first, then after lpcomp. So, I can do basic POCs. 

Whatever is available, either basic Comp or lpcomp, kindly provide me.

Please check with your internal team.

Thanks & Regards,
Pratik