Soft-/firm-/hard-/gate-ware consultant @ Merulogic Oy during the day, hardware research and emulators in evenings. Game Boys, Rust, husband, alopecia patient
Finland
Joined August 2012
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I'll probably stop being active here, but you can find me on the popular B and M alternative apps 😀 I'm verified on both using my personal domain gekkio.fi
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After a long break, I'm opening the cartridge section of gbhwdb.gekkio.fi once again for new submissions! I've added almost all GB/GBC/GBA games to the list and most have no submissions so it's looking a bit empty 😅 You can help by taking photos and sending submissions!
Instructions are here: gbhwdb.gekkio.fi/contribute/…
GBA carts that have a soldered battery obscuring the ROM chip are a bit more complicated, because one photo is required where the battery has been desoldered. Sorry!
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The Game Boy Hardware Database now contains a GBA cartridge section 🎉
gbhwdb.gekkio.fi/cartridges/…
Only a few entries right now but more are coming! Submissions are still officially closed but I accept them from some known good contributors whose submissions require minimal work
"Two schematics releases on the same day? Surely you jest, Gekkio!"
Schematics for the Game Boy 4-player adapter:
github.com/Gekkio/gb-schemat…
Nothing special since Jeff Frohwein's old schematics are already available, but my release also includes unpopulated board photos
Exactly 0 people have requested this one but I reverse engineered it anyway: Game Boy Light DC/DC converter board (LSEP01120A1) 😁
Schematics are here:
github.com/Gekkio/gb-schemat…
An old RE friend/adversary: MBC3B memory bank controller found in some Game Boy cartridges
Relatively modern tech (approx. year 2000-2001) so it's tiny, and limits of optical microscopy are making things difficult. Also: a ton of connections obscure the cells underneath
Working on migrating gb-ctr (github.com/Gekkio/gb-ctr) from LaTeX to typst in order to write more docs easier. Had to write a tikz-timing equivalent for the timing diagrams, and it's starting to look pretty good! Left: LaTeX, Right: typst. Not perfect 1:1 match but good enough
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Time for yet another Game Boy schematics release!
It's something I started working on way back in 2018: Super Game Boy!
Fully traced SGB-R-10 board SVG + schematics that hopefully cover all SGB board revisions (assuming I spotted all the differences!)
github.com/Gekkio/gb-schemat…
Joonas Javanainen retweeted
Wrote a new blog post about Cities: Skylines 2, have a look! blog.paavo.me/cities-skyline… #CitiesSkylines2 #gamedev #MadeWithUnity
I should use the word combatible more often
"Device is compatible with Linux" = it works / should work with Linux
"Device is combatible with Linux" = if you use Linux and fight really hard, possibly losing brain cells / part of your soul in the process, you might get it to work
Current status: trying to untangle this embedded RAM logic from Game Boy MBC2 (Memory Bank Controller) chip 🤔
I've done maybe 98% of the schematics for the MBC2 chip already, but still need to understand some things to verify my schematics are correct.
@qwertymodo
Thanks for the ICD2 clock notes on your Super Game Boy Clock Mod page! However, I'm confused about why AC coupling is needed.
I'm asking because I'm almost ready to release my schematics of SGB (and soon SGB2) but would like to fully understand the circuit first...
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Going down a new rabbit hole: trying to read old floppies, including some from the 80s, originally written by Motorola MDOS 3.x operating system on an unknown machine with a M6809 CPU. Information is limited and I haven't even found docs that describe this disk format precisely
Here's my latest schematics release: original Game Boy (DMG)
github.com/Gekkio/gb-schemat…
Some DMG schematics can already be found on the internet, but they lack some details, have errors, and/or in my opinion have some quality/readability issues.
So here's my take on it...enjoy! 😄
An ad about Sharp SM-812/813/814 microcontrollers, found in Japanese "Processor" magazine No. 4, Aug 1985. These chips contain a CPU core that is a possible precursor of Sharp SM83.
Nintendo Game Boy SoC chips use either this precursor, the SM83, or some variant of one of these.
Pure speculation but I think Sharp failed badly with marketing these chips...I've got other "Processor" magazine issues too, and they're all about the usual suspects (Z80/8086/NEC/etc) with no other mention of Sharp SM-81x, especially the scrapped SM-814.
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