[time-nuts] An embedded NTP server

Bob Camp lists at rtty.us
Tue Jan 1 17:03:49 UTC 2013


Hi

Most of the small micro's don't get very fancy on the clock chain. You are lucky if the VCO is running at twice the CPU clock. In some cases the input capture(s) (and PWM's)  are running directly on the VCO (at say 72 MHz) and the CPU is running at half  or a quarter of that. 

Bob

On Jan 1, 2013, at 11:34 AM, Attila Kinali <attila at kinali.ch> wrote:

> On Tue, 1 Jan 2013 11:23:57 -0500
> Bob Camp <lists at rtty.us> wrote:
> 
>> The only problem you may run into with an input capture is that the
>> 72 MHz may be from an internal VCO that's locked to the external clock
>> source or crystal. Often these micro's don't have VCO's that are as good
>> a one might hope. You will indeed have less than 1 UI jitter, you may
>> not have a whole lot less…
> 
> What about those uC that use a VCO that runs up at several 100MHz (i've
> seen up to 800MHz) and devide it down to what they actually need.
> Shouldnt this improve jitter quite considerably?
> 
> 			Attila Kinali
> 
> -- 
> There is no secret ingredient
>         -- Po, Kung Fu Panda
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.




More information about the time-nuts mailing list