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Interrupt- On digital input egde example
October 20, 2015
1:50 am
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koforever
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September 21, 2015
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About Interrupt- On digital input egde example , 13 pin(digital output pin) turn on when pressed the button 5 times.

But it turn on randomly for me. I don't changed the example code and coplile is successufully completed.

Schmatic is attached below~

My arduino is UNO and Arduino compatible compiler for LabVIEW version is 1.0.0.19.(LabVIEW version is 2015)

Thank you~

(yellow cable -switch& pin 2)//(black cable-GND&switch)

pull-up-1.jpgImage Enlarger

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October 20, 2015
1:21 pm
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LubomirJagos
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August 4, 2015
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Hmmm, you could try to set up defined state for interrupt pin, when button is not pressed, ie. try connect resistor (100kOhm or other big value) between pin and Vcc. Also I haven't look for that example, but when you are using buttons, you have to solve glitches (you think that you pressed button once, but MCU see much more, for it is like you pressed it 5 times because mechanic contacts) so there is hopefully some delay after interrupt or there is electronic solution by connecting capacitor and resistor between pin and GND.

Here is what I think using resistor to set up default level on pin when button is not pressed: https://cdn.sparkfun.com/assets/6/f/b/c/7/511568b6ce395f1b40000000.jpg

October 20, 2015
2:27 pm
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Steffan
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It is likely you are getting button bounce.  When a mechanical button is pressed it may bounce and you may get a few interrupts for a single press.  You can do some of the things LubomirJagos suggested.  You can also change the example to output the actual count to the serial terminal, for example, and you should see the count increase a couple of times when the button is pressed.  This would confirm what is going on.

October 23, 2015
8:18 am
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koforever
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Steffan said
It is likely you are getting button bounce.  When a mechanical button is pressed it may bounce and you may get a few interrupts for a single press.  You can do some of the things LubomirJagos suggested.  You can also change the example to output the actual count to the serial terminal, for example, and you should see the count increase a couple of times when the button is pressed.  This would confirm what is going on.

Thank you!~ LubomirJagos and Steffan.

I confirmed that there are several falling edges when button pressed by using serial monitor.

So I'd like to add some delay to attcehd callback.vi.

But I saw contents that Delays not working inside of attaced callback.vi at the manual.

Is there are any other delay fuction working inside the attached vi?

At the arduino sketch, there is delay_ms() fuction to postpone.

December 1, 2015
7:36 pm
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tronron
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I have a similar issue. I am trying to use zero crossing detection of an AC waveform to trigger a adjustable delay prior to firing a triac to control the brightness of an AC lamp. (very common technique) However, if I cannot create a delay in the interrupt service routine, I cannot accomplish this. Has anybody any ideas how to address this?

December 1, 2015
7:43 pm
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Steffan
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No, you cannot use delays directly in ISRs because the delay requires an interrupt itself.  Thats a common thing with embedded systems.  Refer to here.

Alternatives:

You could not use an interrupt altogether and do your detection, processing and delay in the main loop.

You could set a flag in the interrupt and exit.  Then in the main loop check the flag and then perform your delay after detecting the flag is set.  This is a common thing to do with ISRs.

 

In general you want your ISRs to execute as fast as possible and do a very small amount of work.  Usually set a flag and exit and your main loop does the heavy lifting.

December 1, 2015
7:48 pm
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tronron
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Thanks, Stefan. I'll try that!!!

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