ESP32 external pin wakeup with internal pullup resistor

[mtwellmann]

I also posted this on StackExchange (https://arduino.stackexchange.com/quest ... p-resistor)

I am very new to working with Arduino and any kind of circuits.

I am trying to set up an ESP32 board to wake up with an external trigger by using the command `esp_sleep_enable_ext0_wakeup`

Code: [Select all] [Expand/Collapse]

1.     void setup(){
2.         int MY_PIN = 13;
3.         pinMode(MY_PIN, INPUT_PULLUP);
4.  
5.         int reading = digitalRead(MY_PIN);
6.         if(reading == 1) {
7.             esp_sleep_enable_ext0_wakeup(GPIO_NUM_13,0);
8.         }
9.         else {
10.             esp_sleep_enable_ext0_wakeup(GPIO_NUM_13,1);
11.         }
12.  
13.         // I want the board to wake up every time the state of the switch changes.
14.  
15.         esp_deep_sleep_start();
16.     }

GeSHi © Codebox Plus Extension

I run into troubles with this. The wakeup doesn't happen when I expect it to. I assume it has to do with using an external pull-up resistor. I didn't connect one.

Is there a way to use the internal pull-up resistor for this purpose?

I would appreciate anyone who could explain how this works in general.

The documentation[1] says:

@note This function does not modify pin configuration. The pin is configured in esp_sleep_start, immediately before entering sleep mode.

Maybe I need to configure it correctly with `esp_sleep_pd_config`. Could that be the reason for the pullup resistor not working?

https://github.com/espressif/arduino-es ... sp_sleep.h