I can't even make an LED flash!

[skimask]

How about the prototyping board itself? We've had some discussion here lately about how badly those things will treat you over time, connections not working, intermittent connections, etc. I've started replacing all of mine (got tired of messing with bad connections).
Have you tried putting the chip at the other end of the board or anything like that?

[Archangel]

How about the prototyping board itself? We've had some discussion here lately about how badly those things will treat you over time, connections not working, intermittent connections, etc. I've started replacing all of mine (got tired of messing with bad connections).
Have you tried putting the chip at the other end of the board or anything like that?

Very good point! I just bought 4 replacements last month.

[George]

Thanks for your input so far - but still nothing! The LEDs r the right way around, all the pins metered up ok - I might try the chip on INTRC to see what happens - will let you know how i get on, cheers

[George]

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!

[skimask]

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...

[George]

Thanks for that - I didn't even think to look at the electrical specs I just noted the voltage range on the intro page (didn't help that most of the time I was looking at the 628A datasheet either)