[ntp:questions] how do I lock in average frequency correction
David Woolley
david at ex.djwhome.demon.invalid
Wed Feb 15 21:13:17 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.
Did the XT have an RTC? The original PC certainly did not.
The AT has at least two crystals (4* NTSC and 32768kHz).
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