D1 mini does not resume operation as expected after deep sleep I'm trying to get the D1 mini to return operation after ESP.deepsleep(). The code below compiles and gives the expected output for the first run. Five seconds after the announcement that that the device is going to sleep, there is a brief flash on the on board LED and I get a string of garbage on the serial monitor. Ideas for things to try would be appreciated.

// Testing d1 mini deep sleep
// D0 and RST are connected

/*  platformio.ini:
  [env:d1_mini]
  platform = espressif8266
  board = d1_mini
  framework = arduino
  monitor_speed = 115200
*/

#include &lt;Arduino.h&gt;

void blink();

void setup() {
  Serial.begin(115200);
  pinMode(D0, WAKEUP_PULLUP);
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  blink();
  delay(1000);
  Serial.println("Going for some deep sleep");
  ESP.deepSleep(5e6); // 5e6 is 5 seconds
}

void blink() {
  digitalWrite(LED_BUILTIN, LOW);
  delay(500);
  digitalWrite(LED_BUILTIN, HIGH);
  delay(500);
}


As you can guess I'm running this with platformio. The output on the serial monitor is:

stefan@Cameron ~/.../Projects/Deep sleep $ platformio device monitor --baud 115200
--- Miniterm on /dev/ttyUSB0  115200,8,N,1 ---
--- Quit: Ctrl+C | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---
Going for some deep sleep
sl␀l��|␀�l�|␂␌␌␄�␄l�␌c|ǃ␃�␛�r�cd�c��gg�doo���␌cpp��$sd{d␛�{��o�c�gbx␀�


There is a blink of the LED on the first run, nothing there either after the apparent reset.
The garbage is because the ESP8266 outputs boot information at 76800. This should include the boot reason and may help you understand why the code's not working as expected.

Try changing your Serial speed to 76800 in your code (just so that your messages don't end up being gibberish), use 76800 on platformio's monitor and you should be able to at least see what the D1 says it's doing.

You should see a line that ends in something like:


  rst cause: x, boot mode:(y, z)


x should be 1 ("Power reboot"), 2 ("External reset or wake-up from Deep-sleep" - obviously what you want), 3 ("Software WDT" - the software watchdog went off) or 4 ("Hardware WDT reset" - the hardware watchdog timer went off)

boot mode indicates where the runtime image came from - y should be 3 ("Flash"); anything else is really unlikely for your setup.

There's more info on this at ESP8266 Reset Causes
and Common Fatal
Exception Causes

If you try this please post how it goes! I'd like to hear more about what's going on here.