rainer@hibachi.colorado.edu (Rainer Malzbender) (08/15/90)
Sorry, this is a real RTFM question, but the manuals I have are unclear. I'm currently hacking a 68008 with a 10 Mhz clock, and I'm feeding an 8254 with the same clock. Well, the rub is, it's late at night and I only have an 8253, which will only accept clocks to 2 Mhz. So my brilliant idea is to temporarily use the E pin, which is advertised to be CPU clock/10. Having fortunately avoided 6800 peripherals and micros so far, I know little about this signal. Is it in fact just the CPU clock divided down, or does it do squirrely things when wait states or interrupts happen ? I need it to be rock solid. Thanks for all the fish, er, help. -- Rainer M. Malzbender Technology recapitulates biology. Dept. of Physics (303)492-6829 rainer@hibachi.colorado.edu U. of Colorado, Boulder, USA malzbender%opus@vaxf.colorado.edu
daveh@cbmvax.commodore.com (Dave Haynie) (08/17/90)
In article <24775@boulder.Colorado.EDU> rainer@hibachi.colorado.edu (Rainer Malzbender) writes: >Having fortunately avoided 6800 peripherals and micros so far, I know little >about this signal. Is [the E clock] in fact just the CPU clock divided down, >or does it do squirrely things when wait states or interrupts happen ? I need >it to be rock solid. The E clock is indeed a free running clock, 4 CPU clocks high, 6 CPU clocks low. It's not affected by wait stated, interrupts, or bus arbitration. >Rainer M. Malzbender Technology recapitulates biology. -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy Get that coffee outta my face, put a Margarita in its place!