Hi,
I took a look a your battery.c file. However, I found it had too much overhead code that does not apply to me (I'm using the nRF52 DK nrf52832 and the nRF Connect SDK).
So, I came up with the following code:
battery.c
/**
* @file battery.c
* @author Ernesto Gonzales
* @brief Battery Measurement Module (using nRF52 ADC)
* @version 0.1
* @date 2023-02-16
*
* @copyright Copyright (c) 2023
*
*/
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <zephyr/kernel.h>
#include <zephyr/init.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/drivers/adc.h>
#include <zephyr/drivers/sensor.h>
#include <zephyr/logging/log.h>
#include <zephyr/device.h>
#include <zephyr/devicetree.h>
#include "battery.h"
#define LOG_LEVEL CONFIG_BT_BAS_LOG_LEVEL
LOG_MODULE_REGISTER(BATTERY,CONFIG_ADC_LOG_LEVEL);
#define ZEPHYR_USER DT_PATH(zephyr_user)
//Since the ADC was set with a devicetree overlay, we can call the settings with:
//static const struct adc_channel_cfg ch4_cfg = ADC_CHANNEL_CFG_DT(DT_CHILD(DT_NODELABEL(adc),channel_4));
static const struct adc_dt_spec adc_ch4 = ADC_DT_SPEC_GET_BY_IDX(ZEPHYR_USER,0);
/* Initializes the adc_ch4 to:
{
.dev = DEVICE_DT_GET(DT_NODELABEL(adc)),
.channel_id = 4,
.channel_cfg_dt_node_exists = true,
.channel_cfg = {
.channel_id = 4,
.gain = ADC_GAIN_1_5,
.reference = ADC_REF_INTERNAL,
.acquisition_time = ADC_ACQ_TIME_DEFAULT,
},
.vref_mv = 1200,
.resolution = 12,
.oversampling = 1,
}
*/
bool battery_ok = false;
struct battery_measurement_periphs {
const struct adc_dt_spec *adc_ch4;
struct adc_sequence *adc_seq;
uint16_t raw_data;
};
// Structure only for this file, not to be shared outside
static struct battery_measurement_periphs batt_meas = {
.adc_ch4 = &adc_ch4,
.adc_seq = &(struct adc_sequence) {
.channels = BIT(4),
.buffer = &(batt_meas.raw_data),
.buffer_size = sizeof(batt_meas.raw_data),
.calibrate = true,
},
};
static int battery_meas_setup(const struct device *arg){
const struct battery_measurement_periphs *batt_meas_setup = &batt_meas;
int success;
/*
Check wether device is ready, first.
*/
if(!device_is_ready(batt_meas_setup->adc_ch4->dev)){
LOG_INF("ADC device is NOT ready!");
return -ENOENT;
}
// 0 = success
success = adc_channel_setup_dt(batt_meas_setup->adc_ch4);
if(success != 0){
LOG_INF("Could NOT setup the ADC channel!");
return -ENOENT;
}
battery_ok = true;
LOG_INF("Battery measurement setup correctly!");
return success;
}
//System drivers: Use SYS_INIT() when you need to run a device's function at boot.
SYS_INIT(battery_meas_setup,APPLICATION,CONFIG_APPLICATION_INIT_PRIORITY);
int battery_sample(void){
int success = -ENOENT;
int32_t val;
if(battery_ok){
const struct battery_measurement_periphs *batt_setup = &batt_meas;
struct adc_sequence *adc_seq = batt_setup->adc_seq;
success = adc_read(batt_setup->adc_ch4->dev, adc_seq);
adc_seq->calibrate = false;
if (success == 0){
val = batt_setup->raw_data;
adc_raw_to_millivolts_dt(batt_setup->adc_ch4, &val);
LOG_INF("Battery read (mV) = %d",val);
return (int)(val/(batt_setup->adc_ch4->vref_mv));
} else {
LOG_INF("Error getting ADC reading.");
return success;
}
} else {
LOG_INF("Battery not ok!");
return success;
}
}
and battery.h only shows the battery_sample() function:
/** * @file battery.h * @author Ernesto Gonzales * @brief Battery Measurement Module (using nRF52 ADC) * @version 0.1 * @date 2023-02-16 * * @copyright Copyright (c) 2023 * */ #ifndef APPLICATION_BATTERY_H #define APPLICATION_BATTERY_H /** * @brief Takes sample measurement from the battery connected to the relevant GPIO * * @return an integer representing the battery capacity in percentage (0-100) */ int battery_sample(void); #endif
I also implemented a simple bas and in the main.c I'm using the following function in an infinite loop to measure battery:
static void bas_notify(void)
{
uint8_t batt_level = battery_sample();
if (batt_level > 100) {
LOG_INF("Battery level measured is higher than 100 percent");
}
bt_bas_set_battery_level(batt_level);
}
As you can see from battery.c, I'm obtaining the ADC initialization structure from a Devicetree overlay as follows:
/ {
zephyr,user {
io-channels = <&adc 4>;
};
};
&adc {
#address-cells = <1>;
#size-cells = <0>;
channel@4{
reg = <4>;
zephyr,gain = "ADC_GAIN_1_5";
zephyr,reference = "ADC_REF_INTERNAL";
zephyr,acquisition-time = <ADC_ACQ_TIME(ADC_ACQ_TIME_MICROSECONDS, 20)>;
zephyr,input-positive = <NRF_SAADC_AIN4>;
zephyr,resolution = <12>;
zephyr,vref-mv=<1200>;
};
};
However, I'm getting a failure using the ADC read function, as it's not returning 0.
On top of that I get the following message: "adc_nrfx_saadc: set_resolution: ADC resolution value 0 is not valid"
How can I solve this? I thought the devicetree should've taken care of initializing with the right resolution.
