80 Col Card

2 replies [Last post]
Mot
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Joined: Jun 4 2006
Posts: 2

First, sorry my english is bad. My Question: On which way I can check out in Assembler that is an 80Col Card in the AppleII/II+/IIe.
I write an Program that need the 80 Col Card and must be stop is no there. And I want that this program run on all AppleII.
Have somewhere an assemblerroutine or an example that can this check out correct.

Many thanks for answer
Mot

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mmphosis's picture
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Joined: Aug 18 2005
Posts: 316
finding that card ASM sample code

; This will only work for the particular 80Col Card(s) that you have or know about:

; Go through each slot's ROM to look for signature bytes of the 80Col Card. (This is how the AUTOSTART ROM finds the Disk II Controller Card.)

LDY #$00
STY $00
LDX #$C8 ; start with slot 7 ROM
loop
DEX
CPX #$C0
BEQ nocardfound
STX $01
; check signature byte
LDY #signaturebyteoffset
LDY ($00),Y
CMP #$signaturebyte
BNE loop
; check another signature byte
LDY #signaturebyte2offset
LDY ($00),Y
CMP #$signaturebyte2
BNE loop
; TODO:
; - add in as many signature byte comparisons as you need
; - modify to search for many types of 80 column cards
; using signature tables for each card
; .
; .
; .
cardfound
; indicate that a card was found

nocardfound
RTS

Mot
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Joined: Jun 4 2006
Posts: 2
finding that card

Many thanks for your fast help mmphosis
Mot