EEPROM

PM development, programming, hacking and all that fun stuff.
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sergio-br2
Posts: 1
Joined: May 21st, 2015, 04:37

EEPROM

Post by sergio-br2 » May 21st, 2015, 07:30

Hi, i'm new for all of this :)

I was saving game progress with shared EEP, and then changed to non shared, but I have a problem: how to keep the saves. So I asked JustBurn, and he kindly explained that it was possible to split the saves, you just need to know how it works.

So basically, the EEPROM of 8 kiB (8192 bytes) has: a header, which has game info such as code and name; 6 save slots of 1280 bytes; and a final section which stores few settings and RTC data, at the very bottom.

There is "GBMN" string in the first 4 bytes. Each slot names have 18 bytes consisting of 4 bytes for the game code, 12 bytes for game title, and 2 for checksum.

Slots data start at offset 130.

Image

Thanks for JustBurn for the info!

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YasaSheep
Posts: 195
Joined: November 20th, 2005, 04:04
Location: Portland (Also the discord)
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Re: EEPROM

Post by YasaSheep » May 22nd, 2015, 06:35

Cool, good work, nice to see in image form.

Why is that one section not used** but given specific definitions? Is it only sometimes used? Is it inconsistent? Also what is a "Seconds Timer shadow"?

zoranc
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Joined: August 13th, 2010, 18:13
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Re: EEPROM

Post by zoranc » May 27th, 2015, 11:36

Very nice! I think this deserves entry into PM Wiki.

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