Quote Originally Posted by George View Post
Got it figured! For some reason the thing won't run at under 4.2V I've been trying to run it at 3.0V - I might revert to the 628A as it's better at lower power - on saying that the datasheet for the 628 does say it will run at 3.0V Thanks for your time everyone, I should have bumped the voltage to 5 much earlier. Good suggestion too skimask about the prototype boards I've had trouble with mine in the past but for some reason i still trust them - figure that one out!
Well, the graph in the 16F628 datasheet does show that at 4mhz the minimum required voltage is 4.5v, even though the line goes up from 3.0 to 4.5v at that exact point.
So you have to wonder. Is it 4.5v @ 4mhz or 3.0v @ 4mhz minimum? Must be 4.5v...
And the datasheet also states that the minimum supply voltage is 3v, no matter the speed.
Maybe it'll run at 3.999999 mhz at 4.2v... after all, that's what the graph says!
Live and learn...
Happy PIC'ing...finally...