ADC configuration for nRF5340DK SDK Connect SES

RE: ADC configuration for nRF5340DK SDK Connect SES

Kazi Afroza Sultana — Thu, 17 Mar 2022 12:15:59 GMT

Hello Gulzar,

Sorry for the late reply; I was in sick leave.

How does your overlay file look like?

/ {

zephyr,user {

/* adjust channel number according to pinmux in board.dts */

io-channels = <&adc 0>, <&adc 1>;

};

For these channels to be on AN0 and AN1, the above overlay needs to be added.

Best Regards,

Kazi Afroza Sultana

RE: ADC configuration for nRF5340DK SDK Connect SES

mexco — Sat, 12 Mar 2022 06:17:06 GMT

Hi, I tested the program in the attached file. AN0 and AN1 channels configured to sample two anlaog Inputs. The AN0 channel is sampled very well and the ADC result is avaialbale at index 0 of the buffer. The result of AN1 should be available at index 1 of buffer, but remains zero. Please, have a look at the code. If, you test it with any variable voltage at AN0 and AN1, will be better to verify.

devzone.nordicsemi.com/.../1307.adc.txt

RE: ADC configuration for nRF5340DK SDK Connect SES

Kazi Afroza Sultana — Wed, 23 Feb 2022 15:30:07 GMT

Hello,

1. In the adc.h, if #define BUFFER_SIZE 2 right or wrong to sample 2 analog channels ? If in future, 3 chhannels are required, may I set #define BUFFER_SIZE 3.

The buffer size should be set to N*number of enabled channels, as SCAN mode will sample each channel subsequently and put the result in the RAM buffer as described here: https://infocenter.nordicsemi.com/topic/ps_nrf5340/saadc.html?cp=3_0_0_6_28_4_3#saadc_operationmodes_scan. If you set a buffer size that does not match the number of enabled channels, you will miss samples, or samples will be stored in the buffer in non-deterministic order.

2. In the main file, I adc instantiated by binding and then, set up channels using err = adc_channel_setup() .. function. Is it proper way ?

yes it is.

3. '' #if defined (CONFIG_BOARD_BMS_NRF5340_CPUAPP)
NRF_SAADC->TASKS_CALIBRATEOFFSET = 1''

this task will start offset auto-calibration in SAADC peripheral.

4. I wrote two sample functions, as in adc.c. Is this proper way to add to sequence ? If, wrong any where, may you make changes and attached corrected code file ?

It is ok. I have added a sample code where 2 channels are used. you can look at this as reference. devzone.nordicsemi.com/.../test_5F00_adc.c

5. I called adc sampling functions in repeatitive timer. Is the result of adc from AIN0 and AIN1 be avaialble at same index or at different indices in p_sample_buffer[]

Indexes will be different if both channels are enabled at once and scan mode are used. p_sample_buffer[] will have different values.

Regards,

Kazi Afroza Sultana

RE: ADC configuration for nRF5340DK SDK Connect SES

mexco — Wed, 23 Feb 2022 13:05:58 GMT

Hi, I just need answer of three queries as shown in attached image.

RE: ADC configuration for nRF5340DK SDK Connect SES

Kazi Afroza Sultana — Wed, 23 Feb 2022 09:38:57 GMT

I mean the project folder which contain build file, configure file, cmakelist text file and source file. like the following screenshot:

RE: ADC configuration for nRF5340DK SDK Connect SES

mexco — Wed, 23 Feb 2022 07:49:24 GMT

Hi, here is the code in attached file.

devzone.nordicsemi.com/.../adc_5F00_prg.txt

RE: ADC configuration for nRF5340DK SDK Connect SES

Kazi Afroza Sultana — Wed, 23 Feb 2022 06:59:12 GMT

Hello Gulzar,

I have started looking at your files. Could you please send me the whole project so I can try to reproduce it?

Best Regards,

Kazi Afroza Sultana

RE: ADC configuration for nRF5340DK SDK Connect SES

mexco — Tue, 22 Feb 2022 02:02:32 GMT

Hi, I created an application for testng the sampling of 2 channels on AIN0 and AIN1. The files are attached. I have few doubts.

1. In the adc.h, is #define BUFFER_SIZE 2 right or wrong to sample 2 analog channels ? If in future, 3 chhannels are required, may I set #define BUFFER_SIZE 3.

2. In the main file, I adc instantiated by binding and then, set up channels using err = adc_channel_setup() .. function. Is it proper way ?

3. As, I copied the most coe from sample program, what is meaning of following ?

#if defined (CONFIG_BOARD_BMS_NRF5340_CPUAPP)
NRF_SAADC->TASKS_CALIBRATEOFFSET = 1;

4. I wrote two sample functions, as in adc.c. Is this proper way to add to sequence ? If, wrong any where, may you make changes and attache corrected code file ?

5. I called adc sampling functions in repeatitive timer. Is the result of adc from AIN0 and AIN1 be avaialble at same index or at different indices in p_sample_buffer[].

devzone.nordicsemi.com/.../1641.main.txt devzone.nordicsemi.com/.../1145.adc.h devzone.nordicsemi.com/.../2625.adc.c

Gulzar Singh

RE: ADC configuration for nRF5340DK SDK Connect SES

Kazi Afroza Sultana — Fri, 18 Feb 2022 13:54:04 GMT

Hello,

You have not defined the channel 2 for sampling in your code. You have to do define this.

Best Regards,

Kazi Afroza Sultana

RE: ADC configuration for nRF5340DK SDK Connect SES

mexco — Thu, 17 Feb 2022 05:20:01 GMT

Hi, I tried to use ADC code for single channel AIN0 from the following link.

[quote userid="108933" url="~/f/nordic-q-a/84732/adc-configuration-for-nrf5340dk-sdk-connect-ses/353037#353037"]y0b[/quote]

The code is in attached files (adc.h, adc.c). The device binding fails as shown in attached image.devzone.nordicsemi.com/.../adc.h devzone.nordicsemi.com/.../adc.c

RE: ADC configuration for nRF5340DK SDK Connect SES

Kazi Afroza Sultana — Wed, 16 Feb 2022 18:48:24 GMT

Hello,

SAADC supports 8 channels- One cannel per single-ended input and two channels per differential input. So, If you want two single-ended inputs- you need to create two separate channel configurations; one for AIN0 and one for AIN1 for instance. It has to be defined from the main.c file. Also if you intend to do periodic sample using PPI or collect the sample as part of interrupt handling like this example I linked before https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/reference/peripherals/adc.html?highlight=adc_channel_cfg#c.adc_channel_cfg ; you have to define this in C file.

Best Regards,

Kazi Afroza Sultana

RE: ADC configuration for nRF5340DK SDK Connect SES

mexco — Wed, 16 Feb 2022 01:34:17 GMT

[quote userid="108933" url="~/f/nordic-q-a/84732/adc-configuration-for-nrf5340dk-sdk-connect-ses/353037#353037"]Could you please share your .dts file? [/quote]

Please which .dts file you asking ? Zephyr.dts or elseone ? Zephyr.dts is attached.

devzone.nordicsemi.com/.../1033.zephyr.dts

RE: ADC configuration for nRF5340DK SDK Connect SES

Kazi Afroza Sultana — Tue, 15 Feb 2022 09:41:13 GMT

Hello Gulzar,

It is needed to figure out what should be placed in the devicetree to enable two channels in the SAADC. There may be something wrong with the device tree configuration. nRF5340 has only one SAADC core with 8 input channels mux. Could you please share your .dts file?

Our getting started guide seems to have a section on its own for how to add the ADC peripheral to an example project for example https://devzone.nordicsemi.com/guides/nrf-connect-sdk-guides/b/getting-started/posts/nrf-connect-sdk-tutorial---part-2-ncs-v1-4-0#h185sjwm5882m1bcimiad82dnf4kcy0b

You can also check out ADC driver documentation:https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfx/drivers/adc/index.html?highlight=ad

Thanks.

Best Regards,

Kazi Afroza Sultana