16F877 Wackiness

[Dino308gt4]

That's good to know that I'm not the only one to experience this. I've ordered a few new PICs.

I'll reprogram and set TRISB.7 = 1 as well.

Thank you.

[Dino308gt4]

I mean TRISB.7 = 0

[Dino308gt4]

I found the problem. My 9V battery was low. I swapped it for a fresh one and that fixed it. I can duplicate the problem by swapping in the old one.

Now my next question. What should I use to power my ciruit? I'm using a 7805, and I'm driving a couple of servos, so I kill the 9V batteries quickly.

I looked at a few 9V AC to DC power supplies that I had lying around, but not enough amps I guess. The servos don't move like they should. A fresh 9V drives them at at first but run out quickly.

[mackrackit]

I found the problem. My 9V battery was low. I swapped it for a fresh one and that fixed it. I can duplicate the problem by swapping in the old one.

Now my next question. What should I use to power my ciruit? I'm using a 7805, and I'm driving a couple of servos, so I kill the 9V batteries quickly.

I looked at a few 9V AC to DC power supplies that I had lying around, but not enough amps I guess. The servos don't move like they should. A fresh 9V drives them at at first but run out quickly.

So many options...
A 9 volt Wall Wart with a 500ma output will do just about everything the 7805 will handle. I keep a few 12 Wall Warts around for a quickie. A capacitor across the rails is sometimes needed as some of the Warts are pretty dirty.

A battery pack with 4 AA rechargeable and no regulator. Non rechargeable have to high voltage to run straight.

If you are going to be doing this often (working on PICs and things) a good bench top power supply is the answer.

Whatever you use, be sure to have a a fuse, smaller the better, as near to the source as possible.

[financecatalyst]

Hi
I have jumped on to use a 16F877A, Its the first time I am trying to use an external oscillator : Can you please give me the values you have used for the capacitors which are Grounding the Osc1 & Osc2. I have an 2 Pin ceramic 4MHz Oscillator connect between Osc1 & Osc 2
Thanks

[Dino308gt4]

Hi
I have jumped on to use a 16F877A, Its the first time I am trying to use an external oscillator : Can you please give me the values you have used for the capacitors which are Grounding the Osc1 & Osc2. I have an 2 Pin ceramic 4MHz Oscillator connect between Osc1 & Osc 2
Thanks

I use a pair of 22pf caps.

[financecatalyst]

Thanks for the input. I have followed and something very strange is happening :

I am using an external oscillator 4MHz. My program simply toggles one pin every 30ms.
Problem is that I see sometimes the toggling if I touch the PIC,leg of the capacitor (earth) or touch the bench the circuit is left on and sometimes it works fine and sometimes the led is just on constantly.

I have never ever seen this happening with any PIC I have used till now. What could be the reason for this??? Any advise ????