part4

part4_inputs_outputs/lab1-2/main.c

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+/****************************************************************************
+ * Copyright (C) 2021 by Fabrice Muller                                     *
+ *                                                                          *
+ * This file is useful for ESP32 Design course.                             *
+ *                                                                          *
+ ****************************************************************************/
+
+/**
+ * @file main.c
+ * @author Fabrice Muller
+ * @date 31 Oct. 2021
+ * @brief File containing the lab1-2 of Part 4.
+ *
+ * @see https://github.com/fmuller-pns/esp32-vscode-project-template
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "freertos/FreeRTOSConfig.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+
+#include "esp_timer.h"
+#include "esp_sleep.h"
+
+#include "driver/gpio.h"
+#include "driver/dac.h"
+
+#include "driver/adc.h"
+#include "driver/adc_common.h"
+#include "esp_adc_cal.h"
+
+/*
+ADC : Analog to Digital Converter
+Documentation:
+https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/peripherals/adc.html
+
+
+Command to obtain Vref: 
+espefuse.py --port /dev/ttyUSB0 adc_info
+
+*/
+
+/* Default eFuse Vref in mV */
+#define DEFAULT_VREF 1121
+
+const adc_unit_t unit = ADC_UNIT_1;
+const adc_channel_t channel = ADC_CHANNEL_1;   
+const adc_bits_width_t width = ADC_WIDTH_BIT_10;
+const adc_atten_t atten = ADC_ATTEN_DB_11;
+
+
+esp_adc_cal_characteristics_t *adc_chars;
+
+/**
+ * @brief Print the Characterization type.
+ * 
+ * @param val_type type of characterization
+ */
+static void print_char_val_type(esp_adc_cal_value_t val_type) {
+	switch (val_type) {
+		case ESP_ADC_CAL_VAL_EFUSE_TP:
+        	printf("Characterized using Two Point Value\n");
+			break;
+		case ESP_ADC_CAL_VAL_EFUSE_VREF:
+        	printf("Characterized using eFuse Vref (%d mV)\n", DEFAULT_VREF);
+			break;
+		default:
+        	printf("Characterized using Default Vref\n");
+    }
+}
+
+
+/**
+ * @brief Starting point function
+ * 
+ */
+
+void app_main(void) {
+
+	/* Configure ADC */
+	adc1_config_width(width);	
+   	adc1_config_channel_atten(channel, atten);
+
+    /* Characterize ADC */
+    adc_chars = calloc(1, sizeof(esp_adc_cal_characteristics_t));
+    esp_adc_cal_value_t val_type = esp_adc_cal_characterize(unit, atten, width, DEFAULT_VREF, adc_chars);
+    print_char_val_type(val_type);
+
+	uint16_t measuredValues;
+	int v;
+
+	for (;;) {
+
+		/* Get start time */
+		int64_t t1 = esp_timer_get_time();
+
+		/* Perform measure */
+		v = adc1_get_raw(channel);
+		measuredValues = esp_adc_cal_raw_to_voltage(v, adc_chars);
+
+		/* Get end time */
+		int64_t t2 = esp_timer_get_time();
+
+		/* Print time conversion and voltage */
+		printf("full time conversion = %lld µs\n", t2-t1);
+		printf("V = %d mV\n", measuredValues);
+
+		/* Every second */
+		vTaskDelay(pdMS_TO_TICKS(1000));
+	}
+
+	/* to ensure its exit is clean */
+	vTaskDelete(NULL);
+}
+

part4_inputs_outputs/lab1-2/sdkconfig.defaults

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+CONFIG_ESPTOOLPY_FLASHSIZE_4MB=y
+CONFIG_ESPTOOLPY_FLASHSIZE="4MB"
+