You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
72 lines
1.9 KiB
72 lines
1.9 KiB
#include <stdint.h>
|
|
#include <stdatomic.h>
|
|
#include "analog.h"
|
|
#include "freertos/FreeRTOS.h"
|
|
#include "freertos/task.h"
|
|
#include "driver/gpio.h"
|
|
#include "driver/adc.h"
|
|
#include "esp_adc_cal.h"
|
|
|
|
static esp_adc_cal_characteristics_t *adc_chars;
|
|
|
|
// 32-39
|
|
static const adc1_channel_t channel = ADC1_CHANNEL_4; //GPIO34 if ADC1, GPIO14 if ADC2
|
|
|
|
static float measurement_celsius;
|
|
static const adc_atten_t atten = ADC_ATTEN_DB_0;
|
|
static const adc_unit_t unit = ADC_UNIT_1;
|
|
|
|
static void analog_service(void *arg);
|
|
|
|
static TaskHandle_t hAnalog;
|
|
|
|
#define DEFAULT_VREF 1100
|
|
#define NO_OF_SAMPLES 64
|
|
|
|
void analog_init() {
|
|
printf("Analog init\n");
|
|
|
|
adc1_config_width(ADC_WIDTH_BIT_12);
|
|
adc1_config_channel_atten(channel, atten);
|
|
adc_chars = calloc(1, sizeof(esp_adc_cal_characteristics_t));
|
|
esp_adc_cal_characterize(unit, atten, ADC_WIDTH_BIT_12, DEFAULT_VREF, adc_chars);
|
|
|
|
int rv = xTaskCreate(analog_service, "analog", 4096, NULL, 6, &hAnalog);
|
|
assert (rv == pdPASS);
|
|
}
|
|
|
|
|
|
static void __attribute__((noreturn)) analog_service(void *arg) {
|
|
while (1) {
|
|
uint32_t adc_reading = 0;
|
|
//Multisampling
|
|
for (int i = 0; i < NO_OF_SAMPLES; i++) {
|
|
adc_reading += adc1_get_raw(channel);
|
|
}
|
|
adc_reading /= NO_OF_SAMPLES;
|
|
|
|
//Convert adc_reading to voltage in mV
|
|
uint32_t voltage = esp_adc_cal_raw_to_voltage(adc_reading, adc_chars);
|
|
|
|
#define CORRECT -10;
|
|
voltage += CORRECT;
|
|
|
|
// printf("Raw: %d ... Voltage: %dmV ...", adc_reading, voltage);
|
|
|
|
float volts = voltage * 0.001f;
|
|
|
|
#define R1 4750
|
|
#define V1 3.3f
|
|
float r_pt100 = (volts * R1)/(V1 - volts);
|
|
float celsius = (r_pt100/100.0f - 1.0f) / 3.9083E-3f;
|
|
// printf("Rpt %.3f, Celsius: %.1f\n", r_pt100, celsius);
|
|
|
|
measurement_celsius = celsius;
|
|
|
|
vTaskDelay(pdMS_TO_TICKS(100));
|
|
}
|
|
}
|
|
|
|
float analog_read() {
|
|
return measurement_celsius;
|
|
}
|
|
|