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Re: PS-2 Keyboard for Aplle II ?
- Subject: Re: PS-2 Keyboard for Aplle II ?
- From: "Michael J. Mahon" <mjmahon@aol.com>
- Date: Sat, 31 Dec 2005 01:23:14 -0800
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Linards Ticmanis wrote:
Jay Maynard wrote:
That depends. Just what does an Apple ][ keyboard look like to software?
Plain 7-bit ASCII of key appears in address $C000, whenever the high bit
is set it means a key has been pressed. Accessing $C010 clears out the
previous key and allows a new one to be received.
While the Apple main board takes care of the $C010 keyboard strobe, the
keyboard adapter/encoder must supply a "new key down" strobe in addition
to the 7-bit ASCII. This will do it for a ][ or ][+.
For the //e, it is trickier, since the //e keyboard connector interface
is an unencoded keyswitch matrix plus a few unmatrixed keyswitches. It
would be trickier to emulate such a keyboard with a microcontroller,
since it would have to sync with the main board encoder scan.
-michael
Music synthesis for 8-bit Apple II's!
Home page: http://members.aol.com/MJMahon/
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