Re: PAL Apple IIe (was Re: Apple III?)

[david@uow.edu.au (David Wilson)]

pim@planet.nl (Pim Blokland) writes:
>In article <1e3bdvl.1fvnha2ip2lc0N%dempson@actrix.gen.nz>,
>dempson@actrix.gen.nz (David Empson) wrote:

>> The PAL IIe runs at a slightly lower clock frequency than the NTSC IIe,

>Is that so? I never knew that! I've owned an UK //e for years (made in
>Ireland), and I always assumed the speed was 1.023 MHz, just like the USA
>models. What exactly are the speeds?

The same applies to a EuroPlus. The 14.31818 MHz main xtal is replaced by one
that increases the horizontal timing to 64us (15625Hz). Unfortunately I cannot
read the number off my //e xtal so I will have to try and calculate it:

NTSC	14318180 / 14 / 65 = 15734 Hz
PAL	15625 * 14 * 65 = 14218750

This means the PAL system is running at 99.3% speed of NTSC system.

The cassette and disk systems can handle this 0.7% variation in speed between
NTSC & PAL systems.
--
David Wilson  School of IT & CS, Uni of Wollongong, Australia