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keirf / flashfloppy-osd

On Screen Display and keyboard controller for FlashFloppy
The Unlicense
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Support for BBC Micro/Master decoded keyboard #14

Closed dandoore closed 4 years ago

dandoore commented 4 years ago

Is it possible to assign pins on the “Pill” to utilise the output from the BBC micro keyboard (and from the Master’s compatible PL7 header) to allow keyboard control?

keirf commented 4 years ago

Is the keyboard something that's easy to intercept? I think it's not a serial protocol like Amiga and atari st?

dandoore commented 4 years ago

I’m not overly sure but schematic wise it looks like an 8 bit value returned in parallel on a clock cycle when another pin is asserted, presumably as part of the keyboard scan routine.

dandoore commented 4 years ago

There’s a description of how it works here: http://www.cyberspice.org.uk/blog/2011/04/27/the-bbc-model-b-microcomputer-keyboard-how-it-works/ and the schematic for the Master here (which shows both the Master onboard decode custom chip attached to headers PL11 and PL24 and the BBC B header at PL7) http://mdfs.net/Info/Comp/BBC/Circuits/Master/master2.gif also the keyboard matrix http://mdfs.net/Info/Comp/BBC/Circuits/BBC/bbckbd.gif if that helps!

penfold42 commented 4 years ago

That looks pretty messy for the OSD to also do. Could you use an atmega to sniff the BBC and then clock it out to look like Amiga key presses ?

keirf commented 4 years ago

I don't think this is in scope and, since Beeb doesn't have a side-facing drive like Amiga/ST, it seems low priority too.