PIC output signal not a nice square wave

[ChrisBennet]

Hi everyone,
When I examine the output from the output pins of my 12F675 I don't see a classic square wave. Instead, the Hi to Low transition overshoots i.e. it should have stopped at 0 volts but it continues on and goes negative. It looks this way if the pin is just connected to the oscilloscope or if it also driving a LED.
Is this normal or just a result of using a 60Mhz o-scope and looking too closely?

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thanks in advance,
Chris

P.S. I'm new ot the list, please let me know if posting images like this is causing anyone hardship. I'm thinking of some poor soul using dial up from some remote wilderness.

 

[Nigel Goodwin]

I shouldn't worry about it, you'll never get a perfect squarewave from a micro-controller or micro-processor. I don't see anything wrong with those.

 

[ChrisBennet]

Thanks Nigel!
-Chris

 

[GraveYard_Killer]

i experienced same like that before. disconnect anything that is connected on that port, then check it on oscilloscope. or try using different probe.

 

[bmcculla]

Make sure your probes are compensated correctly too.

Brent