Low frequency audio level detector using PIC ADC?

[cncmachineguy]

This gives me an interrupt frequency of 11.44khz (ie 5.72khz on the scope)

Hank, this still bothers me.

Can you try this:

BMAIN:  'make this your new temporary main for this test
 LATC = LATC ^ %00001000 ' this assumes you can use portc.4 as an output.
 GOTO BMAIN

 'new ISR
LATC = LATC ^ %00000100 ' this will toggle portc.3

the point here is main will just toggle portc.4 and the ISR will toggle portc.3. When you scope these, we will see the speed at which you are running. We expect main to be ~4 instructions, maybe 6. so that would give C.4 a frequency of .5M (.25M) and the ISR should interupt every 7 or 8th time through main.