Content originally posted in LPCWare by mattes on Fri Mar 21 20:14:53 MST 2014
Created SCT functionality that simply counts up. On input signal low an SCT interrupt is created, which then can do the calculation of the signal period. I like to do in a way that the counter is autoreset and continues counting in the background. This way the time spent in IRQ is not delaying the measuring of the next period.
The only thing i found is the LIMIT register, which resets the counter to 0. And then my count sample is gone.
The alternative is to halt the counter, but this interferes again with measuring the next signal.
Or I don't reset the counter (no limit) and it keeps counting. But again by the time I read the counter, it already advanced
and it fudges the result.
I think it is possible with the 'older' timer 16/32 bit. But this is for an lpc810, which for my understanding
does not offer support it.
Is that possible with SCT to 'autobackup' the counter?
I looked at the manual, but the complexity of the SCT offers a lot and I fear that I just overlooked something.
thanx for any advice
