TTGO ESP32 Camera: GPIO 33 can't be selected as wake up pin

ESPHome
1

Hi all. I bought TTGO esp32 camera with PIR sensor for my video doorbell DIY project.
The main idea was to use advantage of deep sleep function. However ESP home says that it is not possible to use PIR sensor GPIO 33 as a wake up pin.
I am not sure whether this some technical or firmware limitation. Could this be changed in future?

thanks in advance.

Kind Regards, Yury.

2

Exactly as stated in the docs. https://esphome.io/components/deep_sleep.html

However the reason for this is unclear to me. For example this page says wake up is possible in GPIO33 https://lastminuteengineers.com/esp32-deep-sleep-wakeup-sources/#ext0-external-wakeup-source

Perhaps @OttoWinter may be able to explain, but if he deosn’t you might want to post an issue on github.

3

Hardware limitation - the GPIO33 is not an RTC pin, and thus is is not accessible from the hw unit that does deep sleep.

4

Thank you guys for clarification. I assume that we can close this topic

5

I have the very greatest respect for your knowledge @OttoWinter, but there are many places on the net which say gpio33 can be used. Am I misinterpreting what I am reading?

6

I have same doubts as @nickrout

I’m really new to ESP32 programming, but after a lot of reading I finally got on this list of RTC_GPIO, also reported on official reference datasheet: https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf

[edit. Specific WROVER-B doc]

The reported list comprises GPIO33/GPIO34/GPIO35

RTC GPIOs

There is RTC GPIO support on the ESP32. The GPIOs routed to the RTC low-power subsystem can be used when the ESP32 is in deep sleep. These RTC GPIOs can be used to wake up the ESP32 from deep sleep when the Ultra Low Power (ULP) co-processor is running. The following GPIOs can be used as an external wake up source.

  • RTC_GPIO0 (GPIO36)
  • RTC_GPIO3 (GPIO39)
  • RTC_GPIO4 (GPIO34)
  • RTC_GPIO5 (GPIO35)
  • RTC_GPIO6 (GPIO25)
  • RTC_GPIO7 (GPIO26)
  • RTC_GPIO8 (GPIO33)
  • RTC_GPIO9 (GPIO32)
  • RTC_GPIO10 (GPIO4)
  • RTC_GPIO11 (GPIO0)
  • RTC_GPIO12 (GPIO2)
  • RTC_GPIO13 (GPIO15)
  • RTC_GPIO14 (GPIO13)
  • RTC_GPIO15 (GPIO12)
  • RTC_GPIO16 (GPIO14)
  • RTC_GPIO17 (GPIO27)

So why runnning the esphome run command I keep getting a message that says
Only pins 0, 2, 4, 12, 13, 14, 15, 25, 26, 27, 32, 39 support wakeup
why I can’t use 33 and 34.

Sorry for the possibly trivial question, but it is not clear to me at all the reason why some GPIO cannot be used.

thanks for any clarification