Re: Apple Graphics Tablet

[buggie@enzu.unm.edu (stephen e buggie)]

What is this --- Apple Graphics Tablet???  Is it a Koala Pad????

SB



: first, let's make sure we're talking about the same thing: the Apple
: Graphics Tablet I know of is rather large and heavy; its pen is
: attached to it with a (too short) cable; it makes funny sounds that
: change when the pen is moved in/out the reach of of the tablet.

: A long time ago I patched a few programs to make use of this tablet.
: To make it clear in the first place - I don't have theese patched
: versions available anymore :-(. But I found a listing from which I can
: tell You this:

: To detect to interface card, I looped over all slots to check in its
: firmware for

: $B0 at location $Cx01 and

: $20 at location $Cx09

: beeing x the slot number. I never found this 'signature' in any other
: firmware.

: To check for the pen position one has to poll the tablet (again beeing
: x the slot number):

: LDA $CFFF ; switch off all extension ROMS

: LDA $Cx00 ; switch on the extension ROM of the tablet

: LDA #$Cx
: STA $07F8 ; initialize some hidden text screen data area for the
: tablet firmware

: JSR $CBB9 ; call well known location ;-) in tablet firmware

: When the pen is in reach of the tablet (up or down) this routine will
: return immediatly. Else it will block - fortunatly the routine checks
: the keyboard strobe ($C010) too and will also return if a key is
: pressed, even if the pen remains out of tablets reach.

: After the routine has returned one can get the information:

: $0280 contains the state of the pen (up or down), I don't know excatly
: any more wich bit it is nor if one can distiguish between 'pen up' and
: 'pen out of reach but key pressed'

: $0281, $0282 contains the absolute X position of the pen

: $0283, $0284 contains the absolute Y position of the pen

: As far as I can remember the values have about 12 bit resolution (!).
: Usually I needed screen coordinates (280 x 192), so I dropped the 4
: least significant bits and did some additional adjustment.
: Unfortunatly I can't remember either what coordinates will be there in
: the 'out of reach but key pressed' case.

: Hope this helps a little - if somebody has success using this method,
: please give me some feedback.

: BTW: I'm working on an Apple ][+ emulator, but suffer from a total
: lack of infos about the Apple ][ mouse (I think it goes into slot 4
: and uses some interrupt stuff ???) due to the fact that I have never
: even seen such a mouse. Any way I'd like to build support for it into
: my emulator. So what ports - what firmware - ... thanks for help in
: advance.

: Oliver

: EOF