The Apple 1 was designed to support a 6502 or 6800 processor. Given
the cost of the 6502, Woz went with that. There are a few out there
considering making 6800-based Apple 1 replicas. The ROM has already
been ported to the 6800 by Eric Smith and with a few MESS patches it
can be emulated. Missing is the cassette ROM.
Is this something that OE could support? Something intended, but
never created? Well 99% created. The only difference is the clock
circuitry and the ROM code.
Attached is the MESS 146 patched files based on Eric's original 143 patches
used for the 2011 Summer RetroChallenge. You'll also find the 6800 Apple-1 ROM
source and binaries.
Also attached is a video of the Apple-1 6800 running a demo program.
Demo programing listing:
1/ 0 : =$FFB4 echo = $FFB4 ; character out sub
2/ 0 : =$FFA2 prbyte = $FFA2 ; print a hex byte
3/ 0 : =$FF21 warm = $FF21 ; warm boot
4/ 0 :
5/ 280 : .org $280 ; start here
6/ 280 :
7/ 280 : CE 02 94 ldx #hello ; load address hello into ldx
8/ 283 : BD 02 89 jsr print
9/ 286 : 7E FF 21 jmp warm
10/ 289 :
11/ 289 : A6 00 print: ldaa ,x
12/ 28B : 27 06 beq +
13/ 28D : BD FF B4 jsr echo
14/ 290 : 08 inx
15/ 291 : 20 F6 bra print
16/ 293 : 39 / rts
17/ 294 :
18/ 294 : 0D 0D 48 45 4C 4C hello: .byt "\r\rHELLO\r\0"
4F 0D 00
Thanks.
Original issue reported on code.google.com by dataj...@gmail.com on 6 Sep 2012 at 4:35
Original issue reported on code.google.com by
dataj...@gmail.comon 6 Sep 2012 at 4:35Attachments: