Doh! First time poster caught out by the subject tag. I am well informed
now. Please read on for my original question.

Rob

On Thu, 2004-01-08 at 22:46, Rob Stockley wrote:
> Hi all. I'm new to pics so please excuse this relatively basic question.
>
> PIC:    16f648a with 20MHz xtal
> Aim:    To measure the charge time of an RC pair using the
>         comparator and timer1 modules.
> Issue:  What is the relationship between ticks and uC frequency? Or
>         more simply, how do I convert the tmr1 value to seconds?
>
> These are my ponderings :)
>
> Assuming no prescaling does one tick occur for every cycle?
>
>         t(s) = 1 / xtal
>
> Which with prescaling would lead to something like...
>
>         t(s) = prescaler / xtal
>
> So with prescaler 1:8...
>
>         t(s) = ( 8 / 20 * 10^6 ) = 0.4us
>
> Am I somewhere over the plate or stuck out in the carpark?
>
> Rob
>
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[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads