Save data on power down

The official pyboard running MicroPython.
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Philosophix
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Joined: Wed Jan 02, 2019 11:45 am

Re: Save data on power down

Post by Philosophix » Fri Jan 04, 2019 3:25 pm

I was accidentally looking at the PYB1.0 picture in the quick reference where there is no VBACK. I have PYB1.1 so after getting the correct picture I added a CR2032 to VBACK and which is working fine with the code you provided. I still can't find any documentation on the stm-module.

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Roberthh
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Location: Rhineland, Europe

Re: Save data on power down

Post by Roberthh » Fri Jan 04, 2019 4:59 pm

I was sure it existed in the docs. But it is in the Wiki: http://wiki.micropython.org/platforms/b ... ard/modstm

Philosophix
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Joined: Wed Jan 02, 2019 11:45 am

Re: Save data on power down

Post by Philosophix » Thu Jan 10, 2019 7:10 am

Saving a number to stm.mem32[stm.RTC+stm.RTC_BKP9R] on power down is working fine, but I need to save another number too which can fit in 16 bits. Is there room for another number and if so, what is the address?

The Wiki: http://wiki.micropython.org/platforms/b ... ard/modstm won't let me access http://wiki.micropython.org/platforms/b ... -const-rtc. It's asking me to sign in so I could not check the documentation.

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pythoncoder
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Re: Save data on power down

Post by pythoncoder » Thu Jan 10, 2019 9:20 am

The battery backed RAM is 4KiB of contiguous space. You'll find some tips on accessing it here.
Peter Hinch

chuckbook
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Joined: Fri Oct 30, 2015 11:55 pm

Re: Save data on power down

Post by chuckbook » Thu Jan 10, 2019 10:53 am

So far MicroPython uses only two of the RTC 32-bit backup registers available (20 on Pyboard, 32 on PYBD).
On a PYBV11 BKP1R..BKB18R are available for general usage.Keeping data inside RTC avoids powering backup RAM.

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