From uchinews!linac!att!pacbell.com!mips!zaphod.mps.ohio-state.edu!rpi!usenet.coe.montana.edu!nntp.uoregon.edu!nntp.uoregon.edu!stevev Thu May 14 11:36:56 CDT 1992 Article: 22201 of alt.folklore.computers Newsgroups: alt.folklore.computers Path: uchinews!linac!att!pacbell.com!mips!zaphod.mps.ohio-state.edu!rpi!usenet.coe.montana.edu!nntp.uoregon.edu!nntp.uoregon.edu!stevev From: stevev@miser.uoregon.edu (Steve VanDevender) Subject: Re: Coleco ADAM In-Reply-To: robm@void.ncsa.uiuc.edu's message of Thu, 14 May 1992 06:43:20 GMT Message-ID: Sender: news@nntp.uoregon.edu Organization: University of Oregon Chemistry Stores References: <1992May14.064320.7567@news.cso.uiuc.edu> Date: 14 May 92 00:09:07 Status: RO In article <1992May14.064320.7567@news.cso.uiuc.edu> robm@void.ncsa.uiuc.edu (Rob McCool) writes: Out of curiosity, does anyone know what sort of main microprocessor the 2600 used? I heard it was a 6502 but opened it and found no such beast... or at least, no such labeled beast. Was it a Z-80? Something 4-bit? Does anyone really care? It was a 6502 derivative (6510?). Specs for the 2600 were posted in alt.sources a long time ago, and I was amazed. The 2600 had 128 bytes of RAM. Yup. And that was mapped into both the zero page and the stack page so it was used for both purposes. 2600 programs basically had to control screen displays scan line by scan line by modifying registers that controlled the player/missile/background graphics. I now have an incredible amount of respect for the Activision programmers who did all my favorite games on that machine, because they earned their money like few other programmers, shoehorning really great games into 2K and 4K ROM cartridges. I'd love to know how they did the pseudorandom terrain generation in _River Raid_. -- Steve VanDevender stevev@greylady.uoregon.edu "Bipedalism--an unrecognized disease affecting over 99% of the population. Symptoms include lack of traffic sense, slow rate of travel, and the classic, easily recognized behavior known as walking." From uchinews!linac!uwm.edu!cs.utexas.edu!swrinde!mips!mips!munnari.oz.au!uniwa!gudjm Thu May 14 11:37:13 CDT 1992 Article: 22205 of alt.folklore.computers Path: uchinews!linac!uwm.edu!cs.utexas.edu!swrinde!mips!mips!munnari.oz.au!uniwa!gudjm From: gudjm@uniwa.uwa.edu.au (D John McKenna) Newsgroups: alt.folklore.computers Subject: Re: Coleco ADAM Message-ID: <1992May14.082557.5418@uniwa.uwa.edu.au> Date: 14 May 92 08:25:57 GMT References: <1992May14.064320.7567@news.cso.uiuc.edu> Organization: University of Western Australia Lines: 20 Status: RO >In article <1992May14.064320.7567@news.cso.uiuc.edu> robm@void.ncsa.uiuc.edu (Rob McCool) writes: > 2600 used? I heard it was a 6502 but opened it and found no such beast... > or at least, no such labeled beast. Was it a Z-80? Something 4-bit? Does > anyone really care? >It was a 6502 derivative (6510?). Specs for the 2600 were posted >in alt.sources a long time ago, and I was amazed. So was I. It wasn't a 6510 - that was a CBM hack for the C64 (they added an almost 8 bit I/O port with data direction register to locations 0 and 1). The 2600 used a 6507 - a REALLY cut down 6502. Only 13 address lines (8K total - the machine allocated 4K to the cartrige and 4K to the rest). Also no IRQ line. Very interesting. All of the timing had to be done in software - timing loops, checking HSYNC and VSYNC flags on the video chip. Blech. I have MUCH respect for the people who wrote such triffic games on them. John West -- gudjm@uniwa.uwa.edu.au For the humour impaired: insert a :-) every 3 words