I am working on a project that requires reading in analog data of 2 ADC channels. The circuits before each of the channels are identical. However, when I give, for example, a 50 Hz sinusoid as an input to both circuits, ADC 2 reads the signal just fine while ADC 1 (all of its channels) read in noise near 0 volts. I tested to see if it was a circuit error by swapping which ADC channel reads each circuit, and ADC 1 still only reads noise near 0 volts telling me that there is either an issue with my code or an issue with the microcontroller (I have tested this on 3 different ESP32 S3s and got the same outcome). Could anyone tell me why this would be happening? Is it a programming issue? Is it a firmware bug? I have left a graph of the voltage reading below as well as the code flashed to the microcontroller.
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#include <stdio.h>
#include <driver/adc.h>
#include "sdkconfig.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_system.h"
#include "esp_spi_flash.h"
#include "esp_adc_cal.h"
void app_main(void)
{
printf("Hello world!\n");
/* ADC Configuration and Callibration Documentation: |
------------------------------------------------------
VRef of the ESP32-S3 is 1100 mV |
Right Channel: GPIO 4 ADC1 Channel 3 |
Left Channel: GPIO 11 ADC2 Channel 0 |
ADC Attenuation Options: |
ADC_ATTEN_DB_0 : 0 - 950 mV |
ADC_ATTEN_DB_2_5 : 0 - 1250 mV |
ADC_ATTEN_DB_6 : 0 - 1750 mV |
ADC_ATTEN_DB_11 : 0 - 3100 mV |
ADC Accuracy Options: |
ADC_WIDTH_9Bit |
ADC_WIDTH_10Bit |
ADC_WIDTH_11Bit |
ADC_WIDTH_12Bit |
ADC_WIDTH_BIT_DEFAULT (Max Bit Width) |
-----------------------------------------------------*/
// Configure desired precision and attenuation for ADC pins
adc1_config_width(ADC_WIDTH_BIT_DEFAULT);
adc1_config_channel_atten(ADC1_CHANNEL_3,ADC_ATTEN_DB_0);
adc2_config_channel_atten(ADC2_CHANNEL_0,ADC_ATTEN_DB_0);
// Create ADC channel characteristics structs for use in calibration functions
esp_adc_cal_characteristics_t adc1_chars;
esp_adc_cal_characteristics_t adc2_chars;
esp_adc_cal_characterize(ADC_UNIT_1,ADC_ATTEN_DB_0,ADC_WIDTH_BIT_DEFAULT,1100,&adc1_chars);
esp_adc_cal_characterize(ADC_UNIT_2,ADC_ATTEN_DB_0,ADC_WIDTH_BIT_DEFAULT,1100,&adc2_chars);
int val1;
int val2;
int n = 44100;
int counter = 0;
float difference;
while(true){
val1 = adc1_get_raw(ADC1_CHANNEL_3);
adc2_get_raw(ADC2_CHANNEL_0,ADC_WIDTH_BIT_DEFAULT,&val2);
int adc1_voltage = esp_adc_cal_raw_to_voltage(val1,&adc1_chars);
int adc2_voltage = esp_adc_cal_raw_to_voltage(val2,&adc2_chars);
printf("\n%d, %d",adc1_voltage,adc2_voltage);
vTaskDelay(1);
counter++;
}
}