ESP8266 Community Forum

- Mon Dec 27, 2021 2:41 pm #93179 Hi all,

This is my first time posting here.

Short version: On an ESP-M3/ESP8285, connecting GPIO16 to RST is causing what appears to be rapid resets, instead of waking up after the set interval. Does seem to work if I use my finger to touch one of the leads on the resistor I have between GPIO16 and RST.

Long version:
I have a little remote sensor project that I've been working on for a while using a Wemos D1 Mini, and I was hoping to downsize it to an ESP-M3/ESP8285. My project translates over fine, except I'm having an issue with the Deep Sleep wakeup on the ESP-M3. On the D1 Mini, I have a diode hooked up from D0 to RST, then I give it a ESP.deepSleep with the appropriate amount of time, and it sleeps then wakes up correctly.

All documentation I find indicates that I need to connect GPIO16 to RST. When I power on the ESP-M3 with that connection, the onboard LED flashes rapidly and my serial console shows random gibberish. I realized that the gibberish repeats with every LED flash, and it is the same string of gibberish that appears once when the unit is powered on without the GPIO16 to RST connection.

I also noticed that without the GPIO16 to RST connection, the unit does go into deep sleep, then after the set time, the onboard LED flashes once.

One weird thing is that it seems to work correctly if I touch one of the leads of the resistor with my finger.

For debugging, I have whittled my code down to this:

Code: Select allvoid setup() {
    Serial.begin(115200);
    Serial.println("");     // Linebreak to clear all the gibberish
    Serial.println("Starting up...");

    delay(3000);
    int naptime = 5000000;
    Serial.println("Nap time");
    ESP.deepSleep(naptime, WAKE_NO_RFCAL);
}

void loop() {
}

And simplified my wiring down to just VCC, GND, TX and RX to my USB serial adaptor, and GPIO16 connected to RST.

Things I have tried:

Googling it for hours before posting here.

I have tried the other GPIOs connected to RST.

I have tried it with and without the diode.

I have tried it with some resistors instead of a diode.

Setting GPIO16 to HIGH in setup().

Tried another ESP-M3/ESP8285 board

- Thu Dec 30, 2021 3:20 pm #93202 Photos of the ESP8285/ESP-M3:

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