[ntp:questions] how do I lock in average frequency correction

David Lord snews at lordynet.org
Wed Feb 15 16:30:55 UTC 2012

John Hasler wrote:
> Dave Hart writes:
>> I believe it had more to do with the Color Graphics Adapter circuitry
>> needing to operate at NTSC-compatible frequency.
> According to my Technical Reference manual the XT and the Portable PC
> used a 14.31818MHz crystal.  This was the only crystal on the
> motherboard.

I just dug out the a86 program I wrote in 1990 for setting
the MM58167 clock chip on an isa card I bought for my XT.


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