Light Sleep Wakeup Fails on ESP32-C6-Super Mini Board (Works on ESP32-WROOM)

[JinwooJungFromSouthKorea]

Related area

light sleep

Hardware specification

ESP32-C6-Super Mini

Is your feature request related to a problem?

Hi everyone,

I'm having trouble getting my ESP32-C6-Super Mini board to wake up from light sleep using a button (and even with a timer). My project works fine on an ESP32-WROOM board, but when I switch to the C6-Super Mini, it enters sleep correctly yet never wakes up.

Below are my two code examples and observations.

Working on ESP32-WROOM (using EXT0):

#include "esp_sleep.h"
#include <Arduino.h>

struct Button {
  uint8_t pin;
  bool pressed;
  void init() {
    pinMode(pin, INPUT_PULLUP);  
    pressed = false;
  }
  bool update() {
    bool now = (digitalRead(pin) == LOW);
    if (now && !pressed) {
      pressed = true;
      return true;
    }
    if (!now) {
      pressed = false;
    }
    return false;
  }
};

Button btn = {25, false};

enum State {
  STATE_AWAKE,
  STATE_WAIT_RELEASE,
  STATE_ENTER_SLEEP,
  STATE_SLEEPING,
  STATE_WAKEUP
};

State currentState = STATE_AWAKE;

void setup() {
  Serial.begin(115200);
  delay(1000);
  Serial.println("ESP32-C6 Light Sleep Toggle (EXT1 Wakeup)");

  btn.init();
  // Using EXT0 wakeup here on pin 25
  esp_sleep_enable_ext0_wakeup((gpio_num_t)btn.pin, 0);
}

void loop() {
  switch (currentState) {
    case STATE_AWAKE:
      if (btn.update()) {
        Serial.println("Button pressed in awake state.");
        currentState = STATE_WAIT_RELEASE;
      }
      break;
    case STATE_WAIT_RELEASE:
      if (digitalRead(btn.pin) == HIGH) {
        Serial.println("Button released. Preparing to enter light sleep...");
        currentState = STATE_ENTER_SLEEP;
      }
      break;
    case STATE_ENTER_SLEEP:
      Serial.println("Entering light sleep mode (EXT1)...");
      currentState = STATE_SLEEPING;
      esp_light_sleep_start();
      currentState = STATE_WAKEUP;
      break;
    case STATE_WAKEUP:
      Serial.println("Woke up from light sleep via EXT1!");
      currentState = STATE_AWAKE;
      break;
  }
  delay(10);
}

Serial Monitor Output on ESP32-WROOM:

css

Button pressed in awake state.
Button released. Preparing to enter light sleep...
Entering light sleep mode (EXT1)...
Woke up from light sleep via EXT1!
...
I also measured the current: it drops from around 60mA to 20mA when in sleep, which seems normal.

Failing on ESP32-C6-Super Mini (using EXT1):

#include "esp_sleep.h"
#include <Arduino.h>

struct Button {
  uint8_t pin;
  bool pressed;
  void init() {
    pinMode(pin, INPUT_PULLUP);
    pressed = false;
  }
  bool update() {
    bool current = (digitalRead(pin) == LOW);
    if (current && !pressed) {
      pressed = true;
      return true;
    }
    if (!current) {
      pressed = false;
    }
    return false;
  }
};

Button btn = {7, false}; // Using GPIO 7

enum State {
  STATE_AWAKE,
  STATE_WAIT_RELEASE,
  STATE_ENTER_SLEEP,
  STATE_SLEEPING,
  STATE_WAKEUP
};

State currentState = STATE_AWAKE;

void setup() {
  Serial.begin(115200);
  delay(1000);
  Serial.println("ESP32 Light Sleep Toggle Example");

  btn.init();

  // Keep RTC peripheral power on for internal pull-up stability
  esp_sleep_pd_config(ESP_PD_DOMAIN_RTC_PERIPH, ESP_PD_OPTION_ON);

  // EXT1 wakeup configuration: wake up when GPIO7 goes LOW
  esp_sleep_enable_ext1_wakeup((1ULL << btn.pin), ESP_EXT1_WAKEUP_ANY_LOW);
}

void loop() {
  switch (currentState) {
    case STATE_AWAKE:
      if (btn.update()) {
        Serial.println("Button pressed in awake state.");
        currentState = STATE_WAIT_RELEASE;
      }
      break;
    case STATE_WAIT_RELEASE:
      if (digitalRead(btn.pin) == HIGH) {
        Serial.println("Button released. Preparing to enter light sleep...");
        currentState = STATE_ENTER_SLEEP;
      }
      break;
    case STATE_ENTER_SLEEP:
      Serial.println("Entering light sleep mode...");
      currentState = STATE_SLEEPING;
      esp_light_sleep_start();
      currentState = STATE_WAKEUP;
      break;
    case STATE_WAKEUP:
      Serial.println("Woke up from light sleep!");
      currentState = STATE_AWAKE;
      break;
  }
  delay(10);
}

Serial Monitor Output on ESP32-C6-Super Mini:

mathematica

ESP32 Light Sleep Toggle Example
Button pressed in awake state.
Button released. Preparing to enter light sleep...
Now, entering sleep...
After entering sleep, the board never wakes up—even when I try pressing the button.

Additional Test with Timer Wakeup Only on ESP32-C6-Super Mini:

#include <Arduino.h>
#include "esp_sleep.h"

const int BUTTON_PIN = 7;

void setup() {
  Serial.begin(115200);
  delay(1000);

  pinMode(BUTTON_PIN, INPUT_PULLUP); // Default HIGH
  gpio_wakeup_enable((gpio_num_t)BUTTON_PIN, GPIO_INTR_LOW_LEVEL);
  esp_sleep_enable_gpio_wakeup();

  // Timer wakeup after 5 seconds
  esp_sleep_enable_timer_wakeup(5000000ULL);

  Serial.println("Entering Light Sleep in 3 seconds...");
  delay(3000);

  Serial.println("Now sleeping...");
  esp_light_sleep_start();

  Serial.println("Woke up!");
}

void loop() {
  delay(1000);
  Serial.println("Sleep again...");
  esp_light_sleep_start();
  Serial.println("Woke up again!");
}

Serial Output:

mathematica

Entering Light Sleep in 3 seconds...
Now sleeping...
After entering sleep, no wakeup occurs.

Summary of the Problem:

On the ESP32-WROOM board, my code works perfectly—the board sleeps and wakes via the button (or EXT0) as expected.
On the ESP32-C6-Super Mini board, while sleep is successfully entered (confirmed by the current drop), the board never wakes up—neither with button wakeup (using EXT1) nor with a timer wakeup.
Questions/Observations:

Could there be a bug or incomplete implementation in the Arduino core for ESP32-C6 affecting wakeup functions (esp_light_sleep_start(), EXT1, GPIO wakeup, timer wakeup)?
Is it possible that the ESP32-C6-Super Mini board’s pin mapping or RTC configuration differs from what the code assumes?
Any suggestions on debugging this or a workaround would be greatly appreciated.
Please let me know if any part of this description seems off or if there are additional details I should include. Thanks in advance for your help!

Feel free to edit or add any hardware details (such as external pull-ups, wiring, etc.) to further clarify your setup. Good luck, and I hope this helps get to the bottom of the issue!

Describe the solution you'd like

I want to wake up ESP32-C6 in light sleep mode

Describe alternatives you've considered

No response

Additional context

No response

I have checked existing list of Feature requests and the Contribution Guide

• I confirm I have checked existing list of Feature requests and Contribution Guide.