add Sleep-with-millis and power-saving library, understand & document power-saving modes

[SpenceKonde]

This library will provide the following functionality:

• Allow sleep where the RTC is used to keep time in standby sleep, and adjust millis() time upon wake, when using any timer except RTC as the timing source.
• Provide a wrapper around sleep when RTC is used to keep time so that user does not have to manage re-sleeping when the ISR fires to update millis()

This will also coincide with testing to better understand sleep modes on the tinyAVR 0-series and 1-series parts.

[SpenceKonde]

Interesting observation in #264 -

Also SLEEP_MODE_PWR_DOWN does not work (with the fore-mentioned sketch)!

Should be investigated here...

[rolland-fx]

Interesting observation in #264 -

Also SLEEP_MODE_PWR_DOWN does not work (with the fore-mentioned sketch)!

Should be investigated here...

Using 2.1.5, SLEEP_MODE_PWR_DOWN seems to be actually SLEEP_MODE_STANDBY from a power point of view.
No sleep, Idle sleep and stanbdy sleep work as intendeed, but Power Down does not seems to achieve the targeted sleep.
In my tests, SLEEP_MODE_PWR_DOWN used to be +/- 6uA on my board. But is now +/- 150uA (at 3.3v), which is what i used to have with SLEEP_MODE_STANDBY .

EDIT :
looks like it's due to a parasitic capacitance on my board, not sure why it was only impacting SLEEP_MODE_PWR_DOWN.

[ArnieO]

Thank you for your great work!
While we're all eagerly waiting for the megaTinySleep library, I am working on a board design using ATtiny1616, where I want the controller to periodically wake up from sleep, do some measurements etc - and go back to sleep.
But I also want to enable external wakeup if a relay input is triggered.
I have found out how to do those things separately, but have not gotten my head around how to get the ATtiny161 to do both. I think what is confusing me is the ISR that seems to need different input parameters for each case, and I have not seen a way to set up two ISRs in parallel.
Any hint on how this might be done?
I could of course add an external RTC chip, but with such a powerful microcontroller with a RTC sitting there ...
Any guidance would be highly appreciated!

[freemovers]

Do you have an issue with the PORT interrupt not working when you are using the PIT interrupt? Here is an example where I used both: https://github.com/freemovers/teddy_bear/blob/main/main.c I can provide some Arduino examples later today as well if needed.

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On Feb 7, 2021, at 1:23 PM, ArnieO ***@***.***> wrote:  Thank you for your great work! While we're all eagerly waiting for the megaTinySleep library, I am working on a board design using ATtiny1616, where I want the controller to periodically wake up from sleep, do some measurements etc - and go back to sleep. But I also want to enable external wakeup if a relay input is triggered. I have found out how to do those things separately, but have not gotten my head around how to get the ATtiny161 to do both. I think what is confusing me is the ISR that seems to need different input parameters for each case, and I have not seen a way to set up two ISRs in parallel. Any hint on how this might be done? I could of course add an external RTC chip, but with such a powerful microcontroller with a RTC sitting there ... Any guidance would be highly appreciated! — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or unsubscribe.

[SpenceKonde]

@ArnieO - For now I think @freemovers is the guy you want to be asking about this; I have yet to have time to put one of these into sleep mode! I do think that this sounds like it just calls for a linear combination of your two pieces of code...?

[ArnieO]

@freemovers : Thank you for your rapid response!
This will be my first application with an ATtiny microcontroller, and I prefer to work in Arduino IDE. Compared to interrupts on other microcontrollers I have some experience with, the ISR syntax for ATtiny confuses me. I have spent a few hours searching for overview information, but have only found bits and pieces. I have not read the datasheet in detail (it is 589 pages...) - and the sections relating to interrupts seem to require basic knowledge on how this is handled.

My confusion:
In Arduino-style coding several ISRs can be defined, each activated by a call to attachInterrupt().
The ISR examples I have seen for ATtiny use one ISR(<register?>) function call, and it looks like the ISR function must always have this name.

So it could well be that my issue is just lack of competence on the coding of this controller family:

• Is it possible to define multiple ISR(xxx) functions in the same code? Your linked code indicates that the answer is YES - which is already a great indication. If you also have Arduino examples available that would surely be a bonus!
• How is priority between those different ISRs handled?

@SpenceKonde : I thought so too until I started looking at code examples. @freemovers will surely be able to provide guidance!