14.3xxx MHz signal on the ISA bus (was Re: Help identifying a

[Tony Duell]

> 
> On 7/20/07, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
> > The OSC signal was the 14.3xxx MHz master clcok signal in the PC and XT...
> >
> > It was used, of course, by the CGA card as the master clock for the video
> > and colour cubcarrier timing. Some other cards used it, often divided
> > down, as a master clock.
> 
> Is there a list anywhere of what cards tended to use that signal?  I

Not that I know of. But it was used on quite a few cards you'd not 
expect, just as a master clock. I know, for example, my POST card 
(displayes the POST errror codes) divides OSC down by 2^n (for a large n) 
to get the display multiplexing signal...

> ask because I manufacture the GG2 Bus+ bus adapter for the Amiga, and,
> because that signal is on the ISA bus, the designer of the card
> slapped a $3 oscillator on it to provide it.  I have a number of
> unassembled cards and, honestly, would like to leave that signal off
> if there's no expectation of folks needing it.

You seem to have a choice. Save $3 and have to put up with people 
complaining (and even worse not complaining, but telling their friends 
that your design doesn;t work right) or do things properly and fit that 
oscillator.

-tony