How to configure the adc periheral in the Device Tree file *.dts

RE: How to configure the adc periheral in the Device Tree file *.dts

Learner — Mon, 19 Oct 2020 18:47:19 GMT

That is fine.

RE: How to configure the adc periheral in the Device Tree file *.dts

Martin Lesund — Mon, 19 Oct 2020 14:09:20 GMT

Hi Mohamed,

I see you are getting support with regards to this in this case: https://devzone.nordicsemi.com/f/nordic-q-a/66702/build-zephyr-elf-versus-build-solution/275634#275634
So lets us keep the discussion there.

RE: How to configure the adc periheral in the Device Tree file *.dts

Learner — Fri, 16 Oct 2020 18:05:45 GMT

Hi Martin,

I give up. I tried few flavours of the overlay file and none worked. The project always fail to load.

# Method 1:
&adc {
# compatible = "nordic,nrf-saadc";
compatible = "voltage-divider";

adc5:adc@... {
label = "AIN_5";
}

adc7:adc@... {
label = "AIN_5";
}

n: node {
io-channels = <&adc5 26>, <&adc7 28>;
io-channel-names = "FOIL", "STRAP";
};
};

# Method 2:
adc0: adc@4000E000 {
compatible = "nordic,nrf-saadc";
# compatible = "voltage-divider";
label = "ADC_0";
};

n: node {
io-channels = <&adc0 4>;
io-channel-names = "AIN_0";
};

Kind regards

Mohamed

RE: How to configure the adc periheral in the Device Tree file *.dts

Learner — Mon, 05 Oct 2020 09:19:10 GMT

Thank you.

Please let me know which one is correct.

Kind regards

RE: How to configure the adc periheral in the Device Tree file *.dts

Martin Lesund — Mon, 05 Oct 2020 09:14:04 GMT

Hi Mohamed,
You are correct, there seems to be some difference in the User guide and the Schematic.

I will check this internally so it will be corrected.

Since the only inconsistency is the user guide, The correct Pin naming is the the schematic and the product spec. which states: P0.04 is AIN0

RE: How to configure the adc periheral in the Device Tree file *.dts

Learner — Fri, 02 Oct 2020 15:34:03 GMT

Hi Martin,

According to the PCA10095 schematics of the nRF5340 PDK (nRF5340-QKAA) pin 4 on P0.04 is AIN0 not AIN1.

Could you please double check. Thank you.

Kind regards

Mohamed

RE: How to configure the adc periheral in the Device Tree file *.dts

Martin Lesund — Fri, 02 Oct 2020 13:11:09 GMT

Hi Learner,
Yes, that should be correct.
p0.04 of the nRF5340, so AIN1

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fug_nrf5340_pdk%2FUG%2Fnrf5340_PDK%2Fhw_analog_pins.html

RE: How to configure the adc periheral in the Device Tree file *.dts

Learner — Thu, 01 Oct 2020 15:56:59 GMT

I have assumed that the number 4 in the line below is the pin number P0.04 which corresponds to adc channel AIN0. Is this right?

io-channels = <&adc0 4>;

RE: How to configure the adc periheral in the Device Tree file *.dts

Learner — Thu, 01 Oct 2020 15:46:41 GMT

Hi Martin,

In NCS Tutorial Part 2- the light intensity controller, there is this section of #defines for the ADC.

/*ADC definitions and includes*/
#include <hal/nrf_saadc.h>
#define ADC_DEVICE_NAME DT_LABEL(DT_INST(0, nordic_nrf_saadc))
#define ADC_RESOLUTION 10
#define ADC_GAIN ADC_GAIN_1_6
#define ADC_REFERENCE ADC_REF_INTERNAL
#define ADC_ACQUISITION_TIME ADC_ACQ_TIME(ADC_ACQ_TIME_MICROSECONDS, 10)
#define ADC_1ST_CHANNEL_ID 0
#define ADC_1ST_CHANNEL_INPUT NRF_SAADC_INPUT_AIN0

Since I am configuring the adc channels using the .overlay with io-channels as you suggested file as follows,

adc0: adc@4000E000 {
label = "ADC_0";
};

n: node {
io-channels = <&adc0 4>;
io-channel-names = "AIN_0"";
};

I think these two lines are not needed anymore, am I right?

#define ADC_1ST_CHANNEL_ID 0
#define ADC_1ST_CHANNEL_INPUT NRF_SAADC_INPUT_AIN0

But I am not sure how the information in the .overlay file will get used by the C code.

Could you please advise on what changes I need to make to the C code to make it use the new info in the overlay file.

Thank you.

RE: How to configure the adc periheral in the Device Tree file *.dts

Martin Lesund — Thu, 01 Oct 2020 13:09:51 GMT

Hi Learner,

Sounds good. Please let me know how it goes, or if you have some additional questions that come up.

RE: How to configure the adc periheral in the Device Tree file *.dts

Learner — Thu, 01 Oct 2020 10:57:42 GMT

Hi Martin,

Thank you for your answer. I did go through the Tutorial Part 2 where the ADC is NOT configured via the .dts file. So, the idea of using io-channels in the .dts file is what I am interested in. I have read some of it and I am not sure I get it. So, I am going to have a go at changing the sample of the light intensity controller in Tutorial 2 and use the .dts file and see if I can get it to work. I will probably need your help at some point to get it to work.

Thank you for your support.

RE: How to configure the adc periheral in the Device Tree file *.dts

Martin Lesund — Thu, 01 Oct 2020 09:37:05 GMT

Hi learner,

In the NCS tutorial you can see how to add a ADC peripheral to your project.

For the .dts you could use "io-channels" as shown here.

Also here is a simple unofficial ADC sample that may be of help.