7 segment clock pulse in

Nicol60

New Member
Hi
I am trying to build a sports timer, I have the 7 segment display working but what I need is a accurate clock pulse. I have tried the pulsout command with the line
Pulsout send a 10us out via pin 5 wait 1.0 sec then loop. Sorry about the description but I am using the Logicator Program I know it is old but then we both match.


This seems to work but I was curious if there is anything better.

Thanks for any help.
 

nick12ab

Senior Member
So it works. Does it work well enough for you?

What do you mean by 'better'? Better accuracy? Having the ability to do something else on the microcontroller in the 1-second wait between pulses?
 

AllyCat

Senior Member
Hi,

Which PICaxe are you using, and what does the Pulse do? The X2 can use an external resonator, which may be more accuate. A 10 us pulse may be quite difficult to "see", even on a 'scope if it's displaying a 1 second timebase.

I can't help with Logicator, but I would change the WAIT 1 to PAUSE 1000 (ms) and the PULSOUT to (say) 100 (=1ms). The DO : LOOP (or a GOTO) will take about 1ms as should the PULSOUT 100. So theretically a PAUSE 998 would give a total period of 1 second.

The PICaxe (internal) clock should definitely have better accuracy than +/- 1%, perhaps as good as 0.1 % if you're lucky (or using an X2). But if you can compare the period (of many pulses) against an accurate electronic watch or clock, then you could trim/calibrate the PICaxe by adjusting the PAUSE value up or down slightly.

Cheers, Alan.
 

Nicol60

New Member
Timed Pluse Out

Hi,

Which PICaxe are you using, and what does the Pulse do? The X2 can use an external resonator, which may be more accuate. A 10 us pulse may be quite difficult to "see", even on a 'scope if it's displaying a 1 second timebase.

I can't help with Logicator, but I would change the WAIT 1 to PAUSE 1000 (ms) and the PULSOUT to (say) 100 (=1ms). The DO : LOOP (or a GOTO) will take about 1ms as should the PULSOUT 100. So theretically a PAUSE 998 would give a total period of 1 second.

The PICaxe (internal) clock should definitely have better accuracy than +/- 1%, perhaps as good as 0.1 % if you're lucky (or using an X2). But if you can compare the period (of many pulses) against an accurate electronic watch or clock, then you could trim/calibrate the PICaxe by adjusting the PAUSE value up or down slightly.

Cheers, Alan.
Gents

Thanks for your reply, I will try what Alan suggested. But to give a little bit more information: I used a 14m2 chip because that was the first that came to hand, proberly over the top as I think the 08 chip would be fine. I have built a seven segment display using a 4026 counter chip and this needs a clock pulse to regulate it. Now I have checked the timer as best I can and it seems to work but although I have been working with the Picaxe for some time it is on and off. So the question was posted to see if there was anything better. Regards Jim
 
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