[time-nuts] PPS Divider (John Ackermann N8UR)

[Bruce Griffiths]

John

Providing a 5MHz output will be difficult/impossible if the PIC is
clocked at 10MHz as a pin will have to be toggled with every instruction.
Surely this will leave no time for executing other instructions to
produce other output frequencies?

It may be possible to do this using inline code with no conditional
branches if and only if one can loop back to the start of the code
without requiring an extra cycle.
It would probably be easier to use a dedicated hardware divider
(external flipflop or internal timer) to generate the 5MHz output.

Bruce

John Ackermann N8UR wrote:
> You could probably get those output frequencies with a custom version of 
> the PIC code.  There shouldn't be any hardware changes needed, though 
> the circuit board layout wasn't optimized for high frequencies so no 
> guarantee on 5 MHz.
>
> The PIC source code will be available, so anyone who wants to modify it 
> for other outputs can have at it.
>
> John
> ----
>
> Mitchell Janoff said the following on 04/01/2009 05:37 PM:
>   
>> In your post, you mentioned that the TADD-2, will have six low impedance
>> outputs that can be individually jumpered to 1 PPS or 10 Hz through 10 kHz
>> outputs. I was wondering if there was a way to provide outputs of 100k, 1MHz
>> and 5MHz (assuming a 10MHz source). I am looking for a way to use a single
>> source such as a z3801 as the standard for my various counters and clocks.
>> There was also a post to build this using divide by 10,2 and 5 IC's. If
>> someone is going to build this circuit can they provide the schematic? If
>> there multiple people interested we can have a circuit board created for
>> this project.
>>
>> Thanks,
>>
>> Mitch
>> KC2MFB
>>
>>
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