88b05f9391
Added component containg API that is able to correct raw ADC readings into a voltage in mV. Also provided a helper function that combines the process of getting the raw ADC1 reading then converting it to a voltage in mV. In doing so, the adc1_get_voltage() function of the ADC driver has been deprecated. Instead there is now adc1_get_raw to obtain the raw ADC1 reading, and adc1_to_voltage() that gets the raw reading and converts all in one function. Functions using the deprecated adc1_get_voltage() have also been updated to use adc1_get_raw(). Conversion is based on ADC characteristics. The characteristics are based on the ADC's v_ref, herefore the appropriate structure and functions have been provided to obtain the ADC characteristics. The existing ADC driver has also been modified by adding a function to route the internal ADC reference voltage to a GPIO allowing users to measure it manually. Relevant documentation has also been updated
52 lines
1.6 KiB
C
52 lines
1.6 KiB
C
/* ADC1 Example
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This example code is in the Public Domain (or CC0 licensed, at your option.)
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Unless required by applicable law or agreed to in writing, this
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software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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CONDITIONS OF ANY KIND, either express or implied.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include "freertos/FreeRTOS.h"
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#include "freertos/task.h"
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#include "freertos/queue.h"
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#include "driver/gpio.h"
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#include "driver/adc.h"
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#include "esp_system.h"
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#include "esp_adc_cal.h"
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/*Note: Different ESP32 modules may have different reference voltages varying from
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* 1000mV to 1200mV. Use #define GET_VREF to route v_ref to a GPIO
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*/
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#define V_REF 1100
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#define ADC1_TEST_CHANNEL (ADC1_CHANNEL_6) //GPIO 34
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//#define V_REF_TO_GPIO //Remove comment on define to route v_ref to GPIO
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void app_main(void)
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{
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#ifndef V_REF_TO_GPIO
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//Init ADC and Characteristics
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esp_adc_cal_characteristics_t characteristics;
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adc1_config_width(ADC_WIDTH_12Bit);
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adc1_config_channel_atten(ADC1_TEST_CHANNEL, ADC_ATTEN_0db);
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esp_adc_cal_get_characteristics(V_REF, ADC_ATTEN_0db, ADC_WIDTH_12Bit, &characteristics);
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uint32_t voltage;
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while(1){
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voltage = adc1_to_voltage(ADC1_TEST_CHANNEL, &characteristics);
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printf("%d mV\n",voltage);
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vTaskDelay(pdMS_TO_TICKS(1000));
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}
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#else
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//Get v_ref
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esp_err_t status;
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status = adc2_vref_to_gpio(GPIO_NUM_25);
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if (status == ESP_OK){
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printf("v_ref routed to GPIO\n");
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}else{
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printf("failed to route v_ref\n");
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}
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fflush(stdout);
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#endif
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}
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