Good day,
on a project I'm working on, I'm using two interrupts. One receives a pulse at a frequency between 1 and 30Hz (an RPM Hall sensor), the other one only once every 10 to 15 minutes (output from another micro processor)
I have noticed in the data that I'm collecting that sometime the data of both these inputs are way off; Very high. It occurs that the interrupt is getting a false signal.
I'm not sure is this is caused by one or the other pulse input, both inputs receiving a pulse at the same time. It might be a power supply issue...
Both signals are regular 5V data signals (no relays or switches).
In teh software, the Interrupt macro is nothing more then a counter; One line of code.
Has anyone experienced this before? if so what have you done.
I could write a small subroutine where these high numbers are being deleted, however that doesn't solve the issue...
Thanks for your input
Henk
jitter on interupt; What would you do
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medelec35
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Re: jitter on interupt; What would you do
Hi henker,
what type of interrupt are you using for pulse detection?
INT(rising/falling edge), IOC ect.
Perhaps if you can post a flowchart, I can try and spot what maybe causing the issue.
Martin
what type of interrupt are you using for pulse detection?
INT(rising/falling edge), IOC ect.
Perhaps if you can post a flowchart, I can try and spot what maybe causing the issue.
Martin
Martin
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henker
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Re: jitter on interupt; What would you do
Martin,
Both interrupts are on the falling edge..
Attached are two snap shots.
Could it be a problem that I only enable the interrupt and leave it enabled?
Thanks
Henk
Both interrupts are on the falling edge..
Attached are two snap shots.
Could it be a problem that I only enable the interrupt and leave it enabled?
Thanks
Henk
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medelec35
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Re: jitter on interupt; What would you do
It would be better If I can see the flowchart.
Since it's calculating RPM, it could be the timing, calculations or variables rolling over that's the issue rather than pulse counting?
Can't tell from screen shots sorry.
Since it's calculating RPM, it could be the timing, calculations or variables rolling over that's the issue rather than pulse counting?
Can't tell from screen shots sorry.
Martin
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henker
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Re: jitter on interupt; What would you do
Personally I don't think that this is a flowcode issue. I think it is a hardware related problem.
I think I should put a scope on the signal and see how clean the pulse is.
After I checked this, I'll let you know.
I think I should put a scope on the signal and see how clean the pulse is.
After I checked this, I'll let you know.
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medelec35
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Re: jitter on interupt; What would you do
You could either do a 1Hz test, or place a toggle calculation within the timer interrupt and toggle a pin on every interrupt.
If this is done for both timer and INT interrupts then that will give a clue to what's happening since you will be be able to monitor both interrupts.
If this is done for both timer and INT interrupts then that will give a clue to what's happening since you will be be able to monitor both interrupts.
Martin