Wanted: MM5740AA/E Keyboard Encoder Chip

5 replies [Last post]
Offline
Joined: Dec 20 2008
Posts: 211

Hi guys,

These come up on eBay every so often, but they are untested or I miss them. Does anyone have any spares of this old chip? I've got an old Apple II that I'd like to use the regular keyboard instead of the PS/2. Smile

-
Pete Rittwage

__________________

-
Peter Rittwage
Apple II/II+ Registry - Register yours today!
http://diskpreservation.com/dp.php?pg=apple_registry

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.
Offline
Joined: Nov 22 2005
Posts: 44
Re: Wanted: MM5740AA/E Keyboard Encoder Chip
Offline
Joined: Nov 22 2005
Posts: 44
Re: Wanted: MM5740AA/E Keyboard Encoder Chip

That will fix a bad one if you have it and also allow for the use of ps/2.

Offline
Joined: Oct 9 2011
Posts: 1063
Re: Wanted: MM5740AA/E Keyboard Encoder Chip

Only if you have the daughter board version of the keyboard. If you have the MM5740AA/E you most likely don't.

Offline
Joined: Dec 20 2008
Posts: 211
Re: Wanted: MM5740AA/E Keyboard Encoder Chip

Mine is the early revision keyboard with no daughterboard... Mike has mentioned making some headway with replaceing the MM5740 with new tech, but nothing yet.

__________________

-
Peter Rittwage
Apple II/II+ Registry - Register yours today!
http://diskpreservation.com/dp.php?pg=apple_registry

Offline
Joined: Jun 5 2008
Posts: 382
Re: Wanted: MM5740AA/E Keyboard Encoder Chip

One could map a MM5740 pinout to an AVR ATMEGA16 with some socket stacking and rewiring. Then you'd have to write the code to scan the keyboard and map to ASCII. It's not rocket science, but it would take a few weekends of heads down work to get a prototype working. Time I don't have. littlediode.com seems to have MM5740/AAE in stock from time to time.

http://www.willegal.net/blog/?p=2567

Regards,
Mike W.