16LF628 Problem

[Ron Marcus]

I am running a 16LF628 on 3 volts @ 8 MHz with a resonator. The chip runs fine, but when I take pin RA1 high, the oscillator stops!?! My first impulse was to pull the chip, but I want to know why it is doing it? I remembered CMCON = 7, and this circuit has worked on 4 exact same boards, with the same code. The current draw is minimal, and I even removed the load, but it still does it. The really wierd part, is that after a random length of time, it starts up where it stopped! Any ideas? Poltergeist?

Ron

[Bruce]

Look at the voltage-frequency chart in the data sheet. You're limited to a MAX frequency at lower operating voltages, and it's affected big time by ambient temperature.

[Ron Marcus]

Thanks Bruce. I replaced the resonator with a 4 MHz part and it ran fine. It was just the erratic behavior with port A that fascinated me.