How to use BS2P measure time like this

Duke

Hello,

I have a problem about measuring time from a Photo Interruper Device.
The pulse looks like this attached picture.

When pulse start running, I what to ignore first 2.5 ms (masking time)
Then measure the down edge of first pulse (High state)·that comes out after masking time.

Please help give me a idea how to write program detect this kind of pulse

Thank you

Duke..

Chris Savage

Duke,

·· There really isn't enough information here to write sample code...What is the state of the signal prior to the pulses coming in?· Is it always one high-pulse prior to the pulse you want to measure?· If so you can simply do a PULSIN twice and ignore the first one.· I'm not sure what you're saying about "down-edge" but if you're measuring the HIGH time, the use the same PULSIN command.

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Chris Savage
Parallax Tech Support
csavage@parallax.com

Duke

Thank you,

The first pulse is always High but it doesn't have raising edge.
When start measure the signal was already High, In this case how can I use pulsin ?

I wonder if there are some commands like stop watch this I can keep lap time.
Do you have more suggestion for me

Chris Savage

Duke,

·· If the signal starts HIGH, then just sit in a tight loop checking for the pin to go LOW.· When it does, do your PULSIN.



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Chris Savage
Parallax Tech Support
csavage@parallax.com

Duke

Like this ?
Loop:
PULSE1
If PIN1 = O then Jump
goto loop

Jump:
...

Chris Savage

Duke,

·· More like:

Main:
DO
LOOP WHILE IN1 = 0
PULSEIN 1, 1, PulseVal

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Chris Savage
Parallax Tech Support
csavage@parallax.com