PGOETZ@LOYVAX.BITNET (04/14/88)
Does anyone have experience with using a 2 MHz 65C02? Can you just drop it in & run the computer? I am certain that it would not initialize nor write to disks correctly, but suspect that it could read from disks. Is this correct? Phil Goetz PGOETZ@LOYVAX
TMURPHY@WPI.BITNET (04/16/88)
Just dropping a faster processor into the computer will do nothing, as it is
still clocked at the old speed. If you changed the clock frequency, the
machine could not access disks at all, if I understand how the Apple does
things. You can pull this trick on a PC, thoough, going from 4.7 MHz to
about 10.
________________________________________________________
Thomas C. Murphy Worcester Polytechnic Institute
Electrical Engineering Dept.
BITNET: TMURPHY@WPI
Arpanet: tmurphy%wpi.bitnet@talcott.harvard.eduspike@bu-cs.BU.EDU (Spike) (04/17/88)
In article <8804152211.aa11958@SMOKE.BRL.ARPA> pgoetz@loyvax.bitnet writes:
<
< Does anyone have experience with using a 2 MHz 65C02? Can you just
<drop it in & run the computer? I am certain that it would not initialize nor
<write to disks correctly, but suspect that it could read from disks. Is this
<correct?
The processor should run fine, however it still will be 1 MHz.
The clock in the apple drives the processor at 1 MHz, so changing the
processor in it will not change the speed. The MHz rating off a chip
is how fast it *can* go. In fact, a common manufacturing technique is
to test the chip at the highest speed, if fails try again at lower
speeds until one is found at which it works.
Could you put a faster clock in? Maybe. You would have to
worry about RAM access, video timing, drive access, etc. The only
thing that is sure is that it would require a great deal of work.
"Last night I had that dream again. I dreamt I had to take a
test, in a Dairy Queen, on another planet."
UUCP: ...!harvard!bu-cs!bu-it!spike INTERNET: spike@bu-it.bu.edu
CSNET: spike%bu-it@bu-cs BITNET: engemnc@bostonu "VPS sucks"
--
->Spikefriedman@porthos.rutgers.edu (Gadi ) (04/17/88)
In article <8804152211.aa11958@SMOKE.BRL.ARPA> PGOETZ@LOYVAX.BITNET writes: > Does anyone have experience with using a 2 MHz 65C02? Can you just > drop it in & run the computer? I am certain that it would not initialize nor > write to disks correctly, but suspect that it could read from disks. Is this > correct? > > Phil Goetz > PGOETZ@LOYVAX You are correct. dropping a 2mhz 65c02 into an Apple IIE/C will work great. It will even initialize and write disks correctly. This is because your Apple already has a 2mhz 65c02 in it. The clock speed is set it run at 1MHZ so these chips provide more reliable performance at lower temps. Notice that you will not get any change in speed by replacing your chip. The only way to speed up the computer is by changing the system clock speed. (I suspect the ZIP chip has its own internal clock). However, just replacing the Xtal with one having a higher speed will not work, since most of the Apple components can not handle the higher clock rate. You will also have trouble with the Apple video, which must access the memory each clock cycle. Gadi. PS. The "speed" of a chip just tells you what its maximum rated speed is. The manufacturer guarantees that the chip will work correctly at the rated speed. The system designer, however, can run the chip at whatever speed they like, though if they run in at too high a speed the chip will not work. -- uucp: {ames, cbosgd, harvard, moss}!rutgers!aramis.rutgers.edu!friedman arpa: FRIEDMAN@ARAMIS.RUTGERS.EDU