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Question regarding interrupt timing..



I am using the LAUNCHl-F28377S.

I noticed a 200mSec delay in an interrupt where I would not expect to see one.

The basics of my main loop

Toggle an I/O to indicate running (Red trace), check IsProcessingComplete var.

If a switch is pressed it sets a IsProcessing to True and toggles and I/O (Yellow Trace).

While all this is happening the ADC in running in continuous mode with a End of Conversion interrupt routine checking the state of the IsProcessing var. 

Currently I removed the code from the Processing function to simply toggle another I/O LED. (Blue trace) 200mSec after the Yellow Trace goes high.

What could be causing this delay? I would expect a few clock cycles to return from the interrupt and then service the ADC recurring Interrupt. I also noticed the delay before the Yellow race goes High it is the same 200mSec. 

I also have an issue where at times the ADC Interrupt does not get ack'd so it stops triggering. (This is a longer issue and I would need to share the project to get help on that one, but could use the help.)

  • Hi Galen,

    We can first start with how you set up the ADC.  It would help if you could provide me with the following information:

    - CPU or System Clock Frequency

    - ADC clock speed setting (or the clock prescaler)

    - How many SOCs did you use (I am assuming you used all 16 SOCs since you indicated running in continuous mode but wanted to be sure).

    - What is the ACQPS (S/H) setting used.

    - What ADC interrupt number were you using to poll your IsProcessing var.

    Regards,

    Joseph