ESP32-C3 cant read all analog values with analogRead()

[kramzarales]

Hello,

I am currently programing an ESP32 C3 devboard which has multiple ADC channels and i would like to read data from 3 different sensors.
The problem is that whenever i use analogRead() with any port it always only shows the measurment on GPIO1.
I have tried it on an ESP32C3-WRoom-02 and also on the ESP32-C3 devmodule 02 with the same result.

I simply connected an external power supply to the pins and when connected to GPIO0 it reads the correct value, but on any other pin it only shows an analog value of 700-900 (i.e. floating pin)
Someone on ESP forum has also reported the same issue

Hardware:

Board: ESP32C3 Dev Module
Core Installation version: 2.0.0. alpha1
IDE name: Arduino IDE
Flash Frequency: 80Mhz
PSRAM enabled: no
Upload Speed: 115200
Computer OS: Windows 10

Description:

When trying to read the analog value of any pin with analogRead(pin); it always reads only the value on GPIO0 (ADC1_CHANNAL0). I can can get any other analog-enabled pin to read the value

Sketch:

//Just a super basic analog read sketch
int sensorPin = 3;
int sensorValue = 0;

void setup() {
// declare the sensorPin as an input doesnt change anything:

Serial.begin(115200);
}

void loop() {
// read the value from the sensor:
sensorValue = analogRead(sensorPin);
Serial.println(sensorValue);
delay(100);
}

Debug Messages:

it compiles and uploads perffectly

[wllis]

I got the same problem too !! so what should I do to solve this issue?

[RudyFiero]

Same here. I tried to follow the code to see if it was a result of the IDF or if it was something in the Arduino code. I wasn't successful. I wanted to try just the IDF alone to check but have not yet found the time to do that.

[kramzarales]

I got the same problem too !! so what should I do to solve this issue?

I later figured out a solution. You can use the #include <driver/adc.h> library (dont need to download it) and then use the folowing example code:

setup:
adc1_config_width(ADC_WIDTH_BIT_12);
adc1_config_channel_atten(ADC1_CHANNEL_3,ADC_ATTEN_DB_11); //set channel atenuation to 11db (optional)
ledcSetup(0, 1000, 8); //channel1, 1000Hz frequency, 8 bit resolution
ledcAttachPin(PWMPin, 1); //map any ADC suported pin to "channel 1"

loop:
ledcWrite(1, duty cycle); // set the duty cycle of "channel 1" (from 0 = 0% to about 1024 =100%)

[wllis]

I got the same problem too !! so what should I do to solve this issue?

I later figured out a solution. You can use the #include <driver/adc.h> library (dont need to download it) and then use the folowing example code:

setup:
adc1_config_width(ADC_WIDTH_BIT_12);
adc1_config_channel_atten(ADC1_CHANNEL_3,ADC_ATTEN_DB_11); //set channel atenuation to 11db (optional)
ledcSetup(0, 1000, 8); //channel1, 1000Hz frequency, 8 bit resolution
ledcAttachPin(PWMPin, 1); //map any ADC suported pin to "channel 1"

loop:
ledcWrite(1, duty cycle); // set the duty cycle of "channel 1" (from 0 = 0% to about 1024 =100%)

Thanks ! I'll try it 😘

[Bastlirovo]

Thank you! I was able to make it work with this setup, ESP32 package 2.0.0:

// Need to add this include
#include <driver/adc.h>

void setup() {
  // ...
  adc1_config_width(ADC_WIDTH_BIT_12);
  adc1_config_channel_atten(ADC1_CHANNEL_0, ADC_ATTEN_DB_11);
  adc1_config_channel_atten(ADC1_CHANNEL_3, ADC_ATTEN_DB_11);
  adc1_config_channel_atten(ADC1_CHANNEL_4, ADC_ATTEN_DB_11);
}

void loop() {
  int analogData0  = adc1_get_raw((adc1_channel_t)0);
  int analogData3  = adc1_get_raw((adc1_channel_t)3);
  int analogData4  = adc1_get_raw((adc1_channel_t)4);
}

[s-light]

i have found this post at the arduino forum

Theory
I believe the problem is that the hardware abstraction layer define in the "esp32-hal-gpio.c" file never defines the pins for the C3 to begin with. ..... There are 2 #defines, one for the ESP32, and one for the ESP32S2, but never one for the ESP32C3. This holds true for both the esp32_gpioMux and the esp32_adc2gpio. I believe, if these arrays are filled out for the C3, this will start working?

The Conclusion???
I really looks like the C3 just doesn't have it's GPIO/ADC pins mapped. The first 22 GPIOs point to Analog channel 0.
And this A/D channel does indeed work as expected.

so the missing peaces are some defines in
cores/esp32/esp32-hal-gpio.c#L49

something like

#elif CONFIG_IDF_TARGET_ESP32C3
const int8_t esp32_adc2gpio[5] = {1, 2, 3, 4, 5};
// GPIO5 == ADC2_0 so we do not want this one?!

and

#elif CONFIG_IDF_TARGET_ESP32C3
    {0x??,  0, -1, -1},
...
    {0, -1, -1, -1}

@me-no-dev could you add these? i have currently no idea how esp32_gpioMux works / what the values mean.....
( i mention you as you added initial c3 support - so i think you have read into the documentation already ;-)

[s-light]

as my comment suggested..
https://docs.espressif.com/projects/esp-idf/en/latest/esp32c3/api-reference/peripherals/adc.html#adc-limitations
ADC2 is used by Wifi - so it is only available if no wifi is used..

[Jason2866]

@s-light ADC1 is fully useable. That ADC2 is conflicting with wifi is the same as for the ESP32. And yes it looks the mapping is not done/there.

[s-light]

i know. my point was:
do we want to include GPIO5 (ADC2_0) as usable adc channel?!
or do we leave it out in the first place as it conflicts if wifi is used...

i personally think it should be included.
(i did not check how the adc1 / adc2 differentiation is implemented in the other ports - and how much extra work this would be..)

[NiklasVoigt]

Ran today into the same error with unusuable GPIO5 (ADC2_0) after manufacturing my pcbs...

do we want to include GPIO5 (ADC2_0) as usable adc channel?!

YES!!!

[mehulsharma21]

i have found this post at the arduino forum

Theory
I believe the problem is that the hardware abstraction layer define in the "esp32-hal-gpio.c" file never defines the pins for the C3 to begin with. ..... There are 2 #defines, one for the ESP32, and one for the ESP32S2, but never one for the ESP32C3. This holds true for both the esp32_gpioMux and the esp32_adc2gpio. I believe, if these arrays are filled out for the C3, this will start working?

The Conclusion???
I really looks like the C3 just doesn't have it's GPIO/ADC pins mapped. The first 22 GPIOs point to Analog channel 0.
And this A/D channel does indeed work as expected.

so the missing peaces are some defines in cores/esp32/esp32-hal-gpio.c#L49

something like

#elif CONFIG_IDF_TARGET_ESP32C3
const int8_t esp32_adc2gpio[5] = {1, 2, 3, 4, 5};
// GPIO5 == ADC2_0 so we do not want this one?!

and

#elif CONFIG_IDF_TARGET_ESP32C3
    {0x??,  0, -1, -1},
...
    {0, -1, -1, -1}

@me-no-dev could you add these? i have currently no idea how esp32_gpioMux works / what the values mean..... ( i mention you as you added initial c3 support - so i think you have read into the documentation already ;-)

@s-light
Hi, Please copy the below table into file esp32-hal-gpio.c

const DRAM_ATTR esp32_gpioMux_t esp32_gpioMux[SOC_GPIO_PIN_COUNT]={
#if CONFIG_IDF_TARGET_ESP32C3
{0x04, -1, 0, -1}, // ADC1_CH0
{0x08, -1, 1, -1}, // ADC1_CH1
{0x0c, -1, 2, -1}, // ADC1_CH2 | FSPIQ
{0x10, -1, 3, -1}, // ADC1_CH3
{0x14, -1, 4, -1}, // MTMS | ADC1_CH4 | FSPIHD
{0x18, -1, 5, -1}, // MTDI | ADC2_CH0 | FSPIWP
{0x1c, -1, -1, -1}, // MTCK | FSPICLK
{0x20, -1, -1, -1}, // MTDO | FSPID
{0x24, -1, -1, -1}, //
{0x28, -1, -1, -1}, //
{0x2c, -1, -1, -1}, // FSPICSO
{0x30, -1, -1, -1}, //
{0x34, -1, -1, -1}, // SPIHD
{0x38, -1, -1, -1}, // SPIWP
{0x3c, -1, -1, -1}, // SPICSO
{0x40, -1, -1, -1}, // SPICLK
{0x44, -1, -1, -1}, // SPID
{0x48, -1, -1, -1}, // SPIQ
{0x4c, -1, -1, -1}, // USB-
{0x50, -1, -1, -1}, // USB+
{0x54, -1, -1, -1}, // U0RXD
{0x58, -1, -1, -1}, // U0TXD

[Jason2866]

With this changes it does now work. Thx @mehulsharma21