wrd@tekigm2.UUCP (Bill Dippert) (08/13/86)
Does anyone know much about the 65C02 chip? I understand from an article in either Antic or ANALOG that it was pin compatible with the 6502 chip. Hence I obtained one and swapped it with my 6502 chip in a 1200XL. Voila, instead of getting a normal screen, I got an all green screen and nothing happened. This was with no cartridge inserted. With a cartridge inserted I could not get anything on the screen. (Altho between tests, I had swapped the 6502 in and out again to check the computer.) Finally I gave up and put the 6502 back in again. Computer worked fine. Only thing that I noticed was that the chip said that it was a R65C02. I thought initially that the R indicated the vendor, but I am wondering -- is there such a thing as a "reverse chip" -- in other words is what I have a 65C02 chip with pins reversed (or backwards)? Has anyone had any success in swapping in 65C02 chips? Or is the Atari 6502 a custom modified 6502? I do notice that the Atari chip has their part number on it and not the JDEC 6502 designation. (Did not Commodore originate the 6502 and if so, is Atari merely trying to hide the origin?) --Bill-- --------------------------------------------------------------------------- Just hacking away at my hardware, a little saw cut here, a new chip there!! ---------------------------------------------------------------------------
jhs@MITRE-BEDFORD.ARPA (08/14/86)
Bill, I think that is a CMOS chip, and as such may not have enough oomph to drive the circuits connected to it in the Atari 1200XL, which are TTL. I think the R means it is a Rockwell chip. A more interesting question would be whether the 65802 chip from The Western Design Center, Inc., would drop in and work! This would give us 6809-like power with upward compatibility, if what I have heard is true. Does anybody know if this would work? -John Sangster jhs@mitre-bedford.arpa
Ishler.WBST@XEROX.COM (08/15/86)
Bill I don't know about the 1200XL but the 6502 in the 800XL has several of the pins relocated and a new signal added(halt).The 800XL repair manual lists the chip as a 6502(modified). Mike