Simple ADC Code

[parman]

Hello,

    I am want to read Analog value from LDR sensor. I am unable to find ADC Input pin in nrf52840 Dongle datasheet but I got it in nrf52840 chip datasheet (page -576) which is - P0.31. But as a newly bid I don't know how to read analog input. Can you give/provide me the code which having an only analog pin declaration, get read value (Please don't include any interrupt base, timer base or any other properties base function).

                                    waiting for your quick support.

                                            Thank you.

   

[haakonsh]

You can use p0.02, p0.29, and p0.31 as analog inputs on the PCA10059 dongle. I suggest you use the PCA10056 DK for any HW interface development (Like an analog input), the dongles as great for when you need more than one prototype, but you don't want to buy 10 PCA10056DKs. 

See the SAADC Example and SAADC — Successive approximation analog-to-digital converter HW documentation. 

[parman]

Hello haakonsh,

     Glad to hear from you,

I found the simple code see -

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

#include "nrf.h"
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include "nrf_drv_adc.h"
#include "nordic_common.h"
#include "boards.h"
#include "nrf_log.h"
#include "app_error.h"
#include "nrf_delay.h"
#include "app_util_platform.h"

static nrf_adc_value_t adc_value; /**< ADC buffer. */
static nrf_drv_adc_channel_t m_channel_config = NRF_DRV_ADC_DEFAULT_CHANNEL(NRF_ADC_CONFIG_INPUT_2);

/**
* @brief Function for main application entry.
*/
int main(void)
{
UNUSED_RETURN_VALUE(NRF_LOG_INIT());
NRF_LOG_PRINTF("ADC example\r\n");

while (true)
{
nrf_drv_adc_sample_convert(&m_channel_config,&adc_value);
NRF_LOG_PRINTF("ADC buffer: %d\r\n",adc_value);
nrf_delay_ms(100);
}
}
/** @} */

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

But I got some error for compiling it for - PCA10059. See - 

Rebuilding ‘blinky_pca10059_mbr’ from solution ‘blinky_pca10059_mbr’ in configuration ‘Release’
Assembling ‘thumb_crt0.s’
Compiling ‘nrf_log_frontend.c’
Compiling ‘nrf_log_str_formatter.c’
Compiling ‘boards.c’
Compiling ‘app_error.c’
Compiling ‘app_error_handler_gcc.c’
Compiling ‘app_error_weak.c’
Compiling ‘app_util_platform.c’
Compiling ‘nrf_assert.c’
Compiling ‘nrf_atomic.c’
Compiling ‘nrf_balloc.c’
Compiling ‘nrf_fprintf.c’
Compiling ‘nrf_fprintf_format.c’
Compiling ‘nrf_memobj.c’
Compiling ‘nrf_ringbuf.c’
Compiling ‘nrf_strerror.c’
Compiling ‘nrfx_atomic.c’
Compiling ‘main.c’
nrf_drv_adc.h: No such file or directory
Assembling ‘ses_startup_nrf52840.s’
Assembling ‘ses_startup_nrf_common.s’
Build failed

   Kindly help me to figure out. 

                                  Waiting for your quick response 

[awneil]

Why don't you just start with one of the ready-made SAADC examples?

And, as haakonsh said, it really is better to start your development on a DK rather than a dongle.

A dongle is great for deploying stuff that you know already works. But, as the name suggests, a Development Kit (DK) is the place to do your development and learning.

How to properly post source code:

[awneil]

Think about this line:

#include "nrf_drv_adc.h"

You have given just the name of the file - but how does the compiler (or, strictly, the preprocessor) know where to find it?

The problem is that it doesn't - so it says:

nrf_drv_adc.h: No such file or directory

The way you tell it where to find your header files is via the Include Paths setting in your Project; for SES:

 

Note that this is standard 'C' (and C++) programming stuff - not specific to Nordic or embedded.

And, while the detail of where to find the setting is specific to SES, the concept is common to all IDEs; eg, in Keil:

or Eclipse:

The setting is passed through to the command line of the underlying toolchain; eg, for GCC:

https://gcc.gnu.org/onlinedocs/cpp/Search-Path.html

EDIT

For SES, see also: https://infocenter.nordicsemi.com/topic/ug_gsg_ses/UG/gsg/add_content_ses.html

#IncludePaths 

[parman]

thank you so much for your guidance Mr. awneil. First I want to understand the codes of all project in-depth. After learning that I will go for the DK kit.

[awneil]

It's probably easier to understand the code by seeing it running in the DK ...