David C Chiu wrote:
"Michael J. Mahon" <mjmahon@aol.com> wrote in message 4oKdnaKrB5aRtsLeRVn-hw@comcast.com">news:4oKdnaKrB5aRtsLeRVn-hw@comcast.com...brad wrote:saw this //c plus for sale on ebay...he posted a pic of making it an 8mhz mod using the 14mhz wdc chip and a crystal change here is the link? http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5823223830&fromMakeTrack=trueIt works. I believe that Wayne (?) has modded his to an even higher speed. Think of it as an "unpotted" Zip Chip. This is the first I've heard of having to upgrade the 65C02 to get it to run faster. Apparently the ones they used in //c+ machines were already high-speed capable.
> > But how does this mod effect the peripheral bus? Is the peripheral > bus clock driven from the same oscillator as the CPU on the IIc+? No. The Zip Chip design is cache-based, and has an asynchronous interface betweed the accelerated processor/cache combo and the processor interface to the rest of the system, which continues to run at standard speed. -michael Music synthesis for 8-bit Apple II's! Home page: http://members.aol.com/MJMahon/ "The wastebasket is our most important design tool--and it is seriously underused."