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Author Topic: 2 Simultaneous Timers  (Read 716 times)

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Offline adaschau2Topic starter

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2 Simultaneous Timers
« on: December 19, 2011, 01:28:24 PM »
Hey all,
     I have been trying to piece together a track timer for my local cub scout troop's pinewood derby (racing small wooden cars down an incline), and I would like the finish line to have two separate timers displaying the finish time of each lane. As I have it set up right now, I need my controller to send a signal of a particular frequency to a "display" circuit which will show the current race time down to milliseconds. Big question is, how can I run both of these timers simultaneously and still be able to stop one lane's timer while having the other continue? Thanks in advance!

Offline absentwizard

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Re: 2 Simultaneous Timers
« Reply #1 on: December 19, 2011, 02:22:40 PM »
Put the clock through a fast AND gate and tie the other input of that gate to the timer stop line. Pull the line low to disable that timer.

Offline adaschau2Topic starter

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Re: 2 Simultaneous Timers
« Reply #2 on: December 19, 2011, 02:34:18 PM »
Aight, thanks absentwizard. I actually thought about doing that, but I had some concerns in regards to accuracy problems due to the and gate having a delay in switching.

Offline absentwizard

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Re: 2 Simultaneous Timers
« Reply #3 on: December 19, 2011, 02:40:42 PM »
There are delays. About 25 nanoseconds. You wanted millisecond accuracy.

Offline adaschau2Topic starter

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Re: 2 Simultaneous Timers
« Reply #4 on: December 19, 2011, 03:38:02 PM »
That I did, that I did.  I certainly do believe that I could suck it up and accept a 25ns loss in accuracy :P Thanks, that clears up my issues as far as that logic goes.

 


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