I assumed he wanted timekeeping accuracy so that would rule out the LM393 which has an accuracy of 10% or worse.
The MCU is still an option but it would need a crystal so the counter might be more convenient.
Hi there Hero,
Are we talking about the same chip, the LM393? That's the 8 pin version of the LM339 more or less right? How did you get an 'accuracy' of 10 percent? That depends on the circuit right?
LM339's are used for time bases for some frequency converters, even some high powered ones
that's why i ask Did i get the part number wrong perhaps?
I was saying before that if the accuracy doesnt have to be super perfect, the internal osc of the PIC can be used. That will get the initial setting close, and a little code adjustment can tune it in very close to the desired frequency. The temperature stability is pretty good too, within 1 percent over the temperature range, so at room temperature it will be very stable.
Yes, the crystal will guarantee near perfect operation though.