esp32 firmware for a toaster reflow oven WIP!!!!!
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reflower/main/analog.c

88 lines
2.4 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;
float reg_meas_history[REG_HISTORY_LEN] = {};
float reg_tset_history[REG_HISTORY_LEN] = {};
uint32_t history_counter = 0;
// TODO move to regulator module (make extern)
float reg_setpoint = 125;
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;
for (int i = 0; i < REG_HISTORY_LEN-1; i++) {
reg_meas_history[i] = reg_meas_history[i+1];
reg_tset_history[i] = reg_tset_history[i+1];
}
reg_meas_history[REG_HISTORY_LEN-1] = celsius;
reg_tset_history[REG_HISTORY_LEN-1] = reg_setpoint;
history_counter = (history_counter + 1) % 20;
vTaskDelay(pdMS_TO_TICKS(500));
}
}
float analog_read() {
return measurement_celsius;
}