I did a little experiment this past weekend playing with the 16f628a- 04 and its internal oscillator. On one breadboard I put 2 16f628's with identical clock programs that display on an LCD. The only difference between the 2 16f628's was I set one up to use the internal oscillator and the other had an external 4mHz oscillator w/ 33 pf capacitors. The difference in the clock accuracy was immediately apparent. I used the clock on my pc as a "control". When I would power up my breadboard, the clock that was powered by the internal oscillator was approx. 25% faster than the clock on my pc. The clock that used an external oscillator was nearly identical to the clock on my pc. It was slightly slower which I attribute to the less than ideal construction on a breadboard. I expected some difference but not that much. Does this surprise anybody? Are any external capacitors required when using the internal oscillator? Just curious. |
16f628 internal oscillator
Started by ●August 4, 2003