Re: IIe enhancement kits!

[Alex Freed <alexf@mirrow.com>]

Don Bruder wrote:
> > Would a 3mhz chip work at a slower clock speed? 

> Yep. Should be a classic "no problemo". The speed rating is a "max speed 
> without troubles starting to show up" number. 

While this is generally true that a CPU will be happy to run slower than 
the maximum rated speed, will the COMPUTER with this chip work is a 
different story.

Specifically the 6502 is "a little asyncronous" - it is using a 
relatively slow clock and some actions happen after a particular DELAY 
after the transition of the clock. This delay is lower in a 3 MHz chip 
than in a 1 MHz chip. And as a result it is a known fact that an
Apple ][+ will NOT work with a 65C02 unless bus buffer chips are 
replaced by faster versions - for example 74Fxx or 74ACxx instead of the 
slow stock 74LSxx.

-Alex.