[time-nuts] Frequency Counter using OCXO and MCU

Brian Lloyd brian at lloyd.com
Wed Mar 12 12:05:25 EDT 2014


On Wed, Mar 12, 2014 at 10:48 AM, d0ct0r <time at patoka.org> wrote:

>
> LCD connected to the same MCU. And it has relation to the core clock too.
> So, nothing on LCD before I reset entire MCU. I think initial incorrect
> core clock reading cause a lot of issues. Probably my only option will be
> to implement some external relay and timer to turn on MCU few seconds after
> OCXO. Or may be to put 10Mhz oscillator to PCB and connect OCXO output in
> parallel to it (not sure if its good idea or it will works).
>

Why not debounce reset from power-up using an RC network and a Schmitt
trigger? Set the time constant so that it will hold the mpu in reset until
power has been asserted long enough to ensure that the OCXO is producing
output.

-- 
Brian Lloyd, WB6RQN/J79BPL
706 Flightline Drive
Spring Branch, TX 78070
brian at lloyd.com
+1.916.877.5067


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