timing deep sleep with external interrupt

[stefbryssinckx]

Hi everyone,


I'm writing code for a battery powered device that measures how long an RTC GPIO is being held high. Because it's battery powered, I want it to be in deep sleep as much as possible. I made a working code using the timer wake up:

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esp_sleep_enable_timer_wakeup(time_in_us)

The esp32 goes into deep sleep for 5 seconds, wakes up, reads the GPIO, assumes it had this status for the last five seconds, stores that information and repeats the process. However, this means it's waking up more than necessary. Also, it's inaccurate because of the assumption made.

What I would like to do is use the external wake up:

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esp_sleep_enable_ext0_wakeup(GPIO_NUM_X, level)

The esp32 would go into deep sleep, wakeup because the GPIO status changed, read how long it had been in deep sleep, store that information and repeat the process.

Is there a way to read how long it had been in deep sleep? If not, suggestions for workarounds are of course welcome. Thanks!