ESP8266 Community Forum

lethe wrote:Normal RAM will indeed not survive deep sleep.
The RTC has a special block of RAM however, that will survive deep sleep. There is example code in the SDK API documentation and a low power demo on github.

That sounds very interesting

Thanks a lot !

I've some example code that does the sleep for one day by using 24 one hour sleeps that i mentioned over in this post, see the sketch funtion sleep1Day. The RTC memory is broken in the latest Arduino code due to Issue 619 though so at them moment its using EEPROM to persist the counting.

torntrousers wrote:I've some example code that does the sleep for one day by using 24 one hour sleeps that i mentioned over in this post, see the sketch funtion sleep1Day. The RTC memory is broken in the latest Arduino code due to Issue 619 though so at them moment its using EEPROM to persist the counting.

I had already found your post on github, after realising that there is actually such a possibility and it was my way to go !

Thank you very much for your help.

And some testing I did earlier would not deep sleep beyond just over HALF an hour. That would be suggesting 31 bits of microseconds not 32 bits, but I didn't check thoroughly.