I am glad to hear it works for you now.

Yes, the battery will drain much faster when using ESP32 deep sleep or light sleep compared to a full shutdown.

You can find the currents for all three modes here.

Thanks
Felix

Just a quick question. Now we have commented out the below lines, so does that means that the battery will drain out much faster as the M5 paper is in light sleep mode?

M5.shutdown();

M5.disableEXTPower(); 

in order to use ESP32 deep sleep ESP32 and external power to the Grove ports need to stay on. Grove power is required for the pull-up resistors in the button unit. (Internal pull-up is too weak.)

I can get your sketch to work if I comment the following lines:

//    M5.shutdown();                    // Shutdown the display and peripherals

//    M5.disableEXTPower();             // Disable external power supply

and adding this line:

gpio_hold_dis((gpio_num_t)M5EPD_EXT_PWR_EN_PIN);

after the other gpio_hold_dis() line.

Plus adding this line:

gpio_hold_en((gpio_num_t)M5EPD_EXT_PWR_EN_PIN);

after the other gpio_hold_en() line.

Thanks
Felix

maybe below lines are the issue?

pinMode(WAKEUP_PIN_26, INPUT_PULLUP);  // Enable internal pull-up for stability
esp_sleep_enable_ext0_wakeup((gpio_num_t)WAKEUP_PIN_33, LOW);  // Wake when pin goes LOW

you enable wakeup on GPIO33 while the pullup is set for GPIO26.

Thanks
Felix

1. Not connected to the charger: The Epaper didn't woke up from the deep sleep, as expected, as you said.

2. Connected with the charger: The Epaper continously keep restarted after executing the shutdown command, until I unplug the button from the PORT B.
   Do you have an idea about this behavior, what is going on with Epaper?

This is the code I am running on Epaper

#include <M5EPD.h>
#include <Arduino.h>

M5EPD_Canvas canvas(&M5.EPD);

#define WAKEUP_PIN_26 26  // GPIO pin on PORT B (G26)
#define WAKEUP_PIN_33 33  // GPIO pin on PORT B (G26)
void setup() {
    wakeupM5OnButtonPressMode();
}

void loop() {
}

void wakeupM5OnButtonPressMode(){  
    M5.begin();
    M5.EPD.SetRotation(90);
    M5.EPD.Clear(true);
    canvas.createCanvas(540, 400);
    canvas.setTextSize(4);

    gpio_hold_dis((gpio_num_t)M5EPD_MAIN_PWR_PIN);
    gpio_deep_sleep_hold_dis();

    // Display battery voltage before shutting down
    Serial.print("\nVoltage before shut down: " + String(M5.getBatteryVoltage() / 1000.0));
    
    // Update the e-ink display with messages
    canvas.drawString("Press button on PORT B to wake up!", 5, 160);
    canvas.drawString("Going to sleep in 5 secs...", 5, 200);
    canvas.pushCanvas(0, 0, UPDATE_MODE_DU4);
    delay(5000);

    // Enter deep sleep
    shutdownEPD();
}

void shutdownEPD() {
    Serial.println("\nShutting down...");
    
    // Display voltage after shutdown (for debugging purposes)
    Serial.print("\nVoltage after shutdown: " + String(M5.getBatteryVoltage() / 1000.0));
    Serial.print("\n*********************************************\n");
    
    // Prepare for deep sleep
    M5.shutdown();                    // Shutdown the display and peripherals
    M5.disableEPDPower();             // Disable e-paper power
    M5.disableEXTPower();             // Disable external power supply
    
    // Configure GPIO for wake-up on button press (PORT B - G26)
    pinMode(WAKEUP_PIN_26, INPUT_PULLUP);  // Enable internal pull-up for stability
    esp_sleep_enable_ext0_wakeup((gpio_num_t)WAKEUP_PIN_33, LOW);  // Wake when pin goes LOW
    
    // Hold power pins to preserve state during deep sleep
    gpio_hold_en((gpio_num_t)M5EPD_MAIN_PWR_PIN);
    gpio_deep_sleep_hold_en();
    
    // Enter deep sleep
    esp_deep_sleep_start();
}

unfortunately that is not possible; all GPIOs (Port A, B and C) and the GPIO used for the side button go directly to ESP32 which is powered off in shutdown mode.

The only two options (I know of) to wakeup M5Paper from shutdown mode are:

• long press of side button
• RTC alarm

Thanks
Felix