Mystery instability of 16f628a

[Davidmarks]

Thanks Bruce. It's back in even as we speak ! Belt, braces and a piece od string as they say !
Cheers

[Archangel]

Hello Davidmarks,
I am curious, are you getting any warnings when you compile? It occurs to me, without the present ability to check MY pbp due to a hard drive failure here at home, What is the default OSC setting in the 16F628A.inc file? Have you opened it and commented it out ? Because if not, your program will use the default osc setting and NOT the one you wrote into your code. So if the default is for using a crystal instead of INTRC_OSC * * * you will in effect have the external crystal ports open to the ether looking for a finger to help start the oscillator by stray capacitance. One more thing, is the " [ " at the beginning of the config statement, in you code or just in your post?

[Davidmarks]

Thanks Joe. As I said in previous post the thing is working OK now. Didn't know about the need to change the inc file for the internal oscillator, but I have now done so and relieved to find it still works. The [ symbol was intended to signify the start of the code.. seem to remember someone telling me that I should do that when posting code. I now have yet another seemingly inexplicable problem. I am programming in circuit with PicKit 2 which has suddenly decided to stop the circuit working if I disconnect it. I have a seperate power supply which is powering the circuit so simply cannot understand why it should stop working when I remove the PicKit2 . It wasn't doing it earlier this week so I am at a loss to know what I have done ( nevertheless I'm pretty sure that I know who is to blame again!)
Cheers
David M

[Archangel]

Microchip sells demo boards at a reasonable price which simply plug into the pickit2. I like them for testing code snippets, easy quick push button changes and viola it is running again, no wires to fuss with. different boards for the 628 and similar vs 690 series. As for who is to blame . . . blame it on the curve, the learning curve, we ALL have lost it on that curve, be careful not to oversteer, so as not to spin out

[mackrackit]

I am programming in circuit with PicKit 2 which has suddenly decided to stop the circuit working if I disconnect it.

Sounds like a MCLR issue. Try _MCLRE_OFF
in your configs.

[Pimentel]

Put a 100nF capacitor near pins 5 and 14 (gnd and vcc) !
Its solve my mistery problems in the pass.

Good luck
Pimentel

[hardcore]

I had problem with 16f628a
After repeating to reprogram IC with the same code it start working as has to be.
Possible disadvantage of 16f628a is some bits of reprogrammed memory do not change their state during programming.
Hope it helps.
hardcore