BS2 Timing question

lfreeze

I have been working on project where timing of am incoming bit is critical.· I must sample a bit of data for 200ms and take action based on receipt of a hi....i am doing this with a simple "do while loop"

Do while recordcount <180
if in8=1 then recordmark.
pause 20
loop

My question is how long in milliseconds will the 'do while" portion take to
execute 180 times?· I have tried various ways to determine this but
have not been successful.

Thanks you for any responses

Larry

dandreae

Your best bet is to use an oscilloscope for an accurrate measurement.· This will allow you to verify the exact execution time of your code.

Dave

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Dave Andreae

Tech Support
dandreae@parallax.com
Http://www.parallax.com

·

Paul Baker

Tracy has done some measurments on the execution speed of commands on various Stamps here: http://www.emesystems.com/BS2speed.htm·But as Dave says oscilloscopes are the best method. You do this by making a pin high when entering the code to be measured, then making it low after the code being measured is done, if youre using a storage scope, get the pulse width from the recorded data, if not loop over the code to be measured.

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·1+1=10

Post Edited (Paul Baker) : 3/30/2006 9:18:43 PM GMT

lfreeze

Thanks for the responses, I guess I'll have the bite the bullet and spend some bucks on
a scope. Any suggestions for minimum scope requirements? I don't want to buy
a cadillac when a ford will do...

Larry

Adrian Schneider

For a scope, these are just a few of many options to consider.
I really recommend using a decent scope when getting serious in electronics - its definitely
worth the extra bucks. I use the Tektronix TDS1000.

decent scope on a low budget:
www.tek.com/products/oscilloscopes/tds1000_tds2000/?wt=550&title=Tektronix%3A%20Products%20%3E%20Oscilloscopes%20Home&label=http%3A//www.tek.com/products/oscilloscopes/tds1000_tds2000/&link=http%3A//www.tek.com/products/oscilloscopes/tds1000_tds2000/

most inexpensive solution:
www.parallax.com/detail.asp?product_id=28119

makes use of your computer's power:
www.picotech.com/

Regards
Adrian

lfreeze

Thank you for the tips on a scope. A quick look at the three suggestions leads me to the parallax scope , but that is based on price only. I'll spend some time looking them over and decide how much budget busting I can stand.

Larry

Paul Baker

The Parallax scope is sufficient for working with stamps.

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6+6=10 (Long live the duodecimal system!)