Hello all,
I have been testing the SAADC example from the peripheral directory.
The goal is to acquire a single sample from SAADC using nrf_drv_saadc_sample_convert() function.
I read over the internet and heard from that nrf_drv will be depricated, so I want to switch to nrfx library.
The issue is that, when I use nrf_drv library I get an ADC output from 0-1023, but nrfx is only from 0-255.
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include "nrf.h"
#include "nrf_drv_saadc.h"
#include "nrf_drv_ppi.h"
#include "nrf_drv_timer.h"
#include "boards.h"
#include "app_error.h"
#include "nrf_delay.h"
#include "app_util_platform.h"
#include "nrf_pwr_mgmt.h"
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
void saadc_event_handler(nrf_drv_saadc_evt_t const * p_event)
{
// Do nothing, as we use blocking mode
}
int saadc_init()
{
int ret = nrf_drv_saadc_init(NULL, saadc_event_handler);
if (ret) return ret;
const nrf_saadc_channel_config_t saadc_config = {
.resistor_p = NRF_SAADC_RESISTOR_DISABLED,
.resistor_n = NRF_SAADC_RESISTOR_DISABLED,
.gain = NRF_SAADC_GAIN1_4,
.reference = NRF_SAADC_REFERENCE_VDD4,
.acq_time = NRF_SAADC_ACQTIME_10US,
.mode = NRF_SAADC_MODE_SINGLE_ENDED,
.burst = NRF_SAADC_BURST_DISABLED,
.pin_p = NRF_SAADC_INPUT_AIN0,
.pin_n = NRF_SAADC_INPUT_DISABLED
};
ret = nrf_drv_saadc_channel_init(0, &saadc_config);
return ret;
}
int saadc_measure()
{
nrf_saadc_value_t value;
nrf_drv_saadc_sample_convert(0, &value);
return value;
}
double convertAdc(int16_t value)
{
return value * (3.3/1023);
}
int main()
{
uint32_t err_code = NRF_LOG_INIT(NULL);
APP_ERROR_CHECK(err_code);
NRF_LOG_DEFAULT_BACKENDS_INIT();
ret_code_t ret_code = nrf_pwr_mgmt_init();
APP_ERROR_CHECK(ret_code);
NRF_LOG_INFO("SAADC Start");
saadc_init();
int16_t measurement;
while (1)
{
nrf_delay_ms(100);
measurement = saadc_measure();
float voltage = convertAdc(measurement);
//NRF_LOG_INFO("Measured value = %ld", measurement);
NRF_LOG_INFO("Voltage: " NRF_LOG_FLOAT_MARKER "V\r\n", NRF_LOG_FLOAT(voltage));
nrf_pwr_mgmt_run();
NRF_LOG_FLUSH();
}
}
Above is the code with nrf_drv library (Desired)
void saadc_event_handler(nrf_drv_saadc_evt_t const * p_event)
{
// Do nothing, as we use blocking mode
}
int saadc_init()
{
int ret = nrfx_saadc_init(NULL, saadc_event_handler);
if (ret) return ret;
const nrf_saadc_channel_config_t saadc_config = {
.resistor_p = NRF_SAADC_RESISTOR_DISABLED,
.resistor_n = NRF_SAADC_RESISTOR_DISABLED,
.gain = NRF_SAADC_GAIN1_4,
.reference = NRF_SAADC_REFERENCE_VDD4,
.acq_time = NRF_SAADC_ACQTIME_10US,
.mode = NRF_SAADC_MODE_SINGLE_ENDED,
.burst = NRF_SAADC_BURST_DISABLED,
.pin_p = NRF_SAADC_INPUT_AIN0,
.pin_n = NRF_SAADC_INPUT_DISABLED
};
ret = nrfx_saadc_channel_init(0, &saadc_config);
return ret;
}
int saadc_measure()
{
nrf_saadc_value_t value;
nrfx_saadc_sample_convert(0, &value);
return value;
}
double convertAdc(int16_t value)
{
return value * (3.3/1023);
}
int main()
{
uint32_t err_code = NRF_LOG_INIT(NULL);
APP_ERROR_CHECK(err_code);
NRF_LOG_DEFAULT_BACKENDS_INIT();
ret_code_t ret_code = nrf_pwr_mgmt_init();
APP_ERROR_CHECK(ret_code);
NRF_LOG_INFO("SAADC Start");
saadc_init();
int16_t measurement;
while (1)
{
nrf_delay_ms(100);
measurement = saadc_measure();
float voltage = convertAdc(measurement);
//NRF_LOG_INFO("Measured value = %ld", measurement);
NRF_LOG_INFO("Voltage: " NRF_LOG_FLOAT_MARKER "V\r\n", NRF_LOG_FLOAT(voltage));
nrf_pwr_mgmt_run();
NRF_LOG_FLUSH();
}
}
Above is the code for SAADC with nrfx which gives a range of 0-255 (Not desired)
I am not able to figure out about how to get SAADC working with nrfx library.
May be I am missing out on something. Could you help me out?
Thanks!
Best regards,
Navin
