Isolate GPIO (not RTC) during deep-sleep

[davdav]

Hi everybody,

I have the necessity to isolate some GPIO (not RTC) like GPIO16, GPIO18, GPIO22 and GPIO23 during deepsleep in ESP32-WROOM32D module.

In my case GPIO22 and GPIO23 are outputs and using

Code: Select all

	gpio_hold_en();
	gpio_deep_sleep_hold_en();

I'm able to fix their status during deep-sleep and wakeup stub.


GPIO16 and GPIO18 are used for I2C bus and have external pull-up resistors. Before entring in deep-sleep should I change them to output mode, set high level and hold their status? Or they are automatically isolated from the external resistors?

[ESP_houwenxiang]

Hi, davdav
You do not need to reconfigure the GPIO mode before entering deep-sleep. When `gpio_deep_sleep_hold_en` is called, all digital GPIOs will remain in their current state. But after the chip wakes up from deep sleep and calls `gpio_deep_sleep_hold_dis`, all digital GPIOs will be reset to the default mode. In this case, you need to reconfigure the GPIO before this function call.

thanks !!

[davdav]

Hi, davdav
You do not need to reconfigure the GPIO mode before entering deep-sleep. When `gpio_deep_sleep_hold_en` is called, all digital GPIOs will remain in their current state. But after the chip wakes up from deep sleep and calls `gpio_deep_sleep_hold_dis`, all digital GPIOs will be reset to the default mode. In this case, you need to reconfigure the GPIO before this function call.

thanks !!

Thank you @ESP_houwenxiang,

In practice, if device wakes-up and I DON'T call `gpio_deep_sleep_hold_dis`, digital GPIO (not RTC) inputs should work as before entering in deep-sleep, right? I.e. in my particular case GPIO16 and GPIO18 will still work as I2C bus. Consider that at every start-up (not regarding if it is a wake up from or a power-on) I init the I2C driver.

However, I will do some test in order to understand how it works, because documentation in my opininon is not so clear regarding the "hold" functionality.

thanks

[ESP_houwenxiang]

Yes, all states will remain in the state before sleep. the GPIO can not input or output as you wanted. so, `gpio_deep_sleep_hold_dis` should be called if you want I2C bus works.

[andrewandroid]

Hey davdav and ESP_houwenxiang

Thanks for posting details.

I have exactly the same problem, I believe. Did you get this working?

Here's my setup:
I have three non-RTC GPIO pins (16, 17, 18), and I want them to stay HIGH during deep sleep.

I'm using Arduino IDE:
```
// Stop doing PWM.
ledcDetachPin(16);
pinMode(16,OUTPUT);
digitalWrite(16, HIGH);

ledcDetachPin(17);
pinMode(17,OUTPUT);
digitalWrite(17, HIGH);

ledcDetachPin(18);
pinMode(18,OUTPUT);
digitalWrite(18, HIGH);

gpio_hold_en((gpio_num_t) 16);
gpio_hold_en((gpio_num_t) 17);
gpio_hold_en((gpio_num_t) 18);
gpio_deep_sleep_hold_en();
delay(10000);
esp_deep_sleep_start();
```

Problem:
Pin 16 and 17 go to LOW as soon as I call `esp_deep_sleep_start()`. They should stay HIGH.

Did your IDF code work?

I've read a number of other posts about this topic, and I'm not sure what the problem is.

Would really appreciate any help or hints anyone can give.

Thanks,
Andrew