trouble with my 16f84a

[cavity creep]

Would you believe that did the trick?????

Thanks you so much! Can you give a little insight into what exactly is going on with the timers?I'm certain I'll run into this again.

Thanks again to everybody for their insight

Shawn

[mackrackit]

The data sheet says it best. If not, let us know.

6.10 Watchdog Timer (WDT)
The Watchdog Timer is a free running On-Chip RC
Oscillator which does not require any external
components. This RC oscillator is separate from the
RC oscillator of the OSC1/CLKIN pin. That means that
the WDT will run even if the clock on the OSC1/CLKIN
and OSC2/CLKOUT pins of the device has been
stopped, for example, by execution of a SLEEP
instruction. During normal operation, a WDT time-out
generates a device RESET. If the device is in SLEEP
mode, a WDT wake-up causes the device to wake-up
and continue with normal operation. The WDT can be
permanently disabled by programming configuration bit
WDTE as a '0' (Section 6.1).
6.10.1 WDT PERIOD
The WDT has a nominal time-out period of 18 ms, (with
no prescaler). The time-out periods vary with
temperature, VDD and process variations from part to
part (see DC specs). If longer time-out periods are
desired, a prescaler with a division ratio of up to 1:128
can be assigned to the WDT under software control by
writing to the OPTION_REG register. Thus, time-out
periods up to 2.3 seconds can be realized.
The CLRWDT and SLEEP instructions clear the WDT
and the postscaler (if assigned to the WDT) and prevent
it from timing out and generating a device
RESETcondition.
The TO bit in the STATUS register will be cleared upon
a WDT time-out.

[cavity creep]

Well here's the strange thing.Shutting off the watchdog timer works quite well on one PIC.It functions as it is supposed to.However, I tried the exact same thing in the exact same circuit with the other pic, and it doesn't work. Same old problem. Also the book I've been referencing states to set the watchdog and power up timers on.
Any thoughts?

[mackrackit]

Well here's the strange thing.Shutting off the watchdog timer works quite well on one PIC.It functions as it is supposed to.However, I tried the exact same thing in the exact same circuit with the other pic, and it doesn't work. Same old problem. Also the book I've been referencing states to set the watchdog and power up timers on.
Any thoughts?

Just guessing...as usual.

Try reading the PIC and see if that hex matches the hex generated by the assembler. The config part might not be getting programed correctly.

If they are not the same.

Erase all but the chips ID if the EPIC has that setting. Then write to the chip program memory and config settings.

[cavity creep]

Nope.They look the same.

[Acetronics2]

Hi,

Works fine, as written ...

Hardware problem ( or config ) ... then !!!

Alain

[Bruce]

Have you tried the code example I posted above?

[cavity creep]

Hi,

Works fine, as written ...

Hardware problem ( or config ) ... then !!!

Alain

I'm going to have to agree with you I think.I suppose I have one good PIC and one bad, but I would think I would have difficulty reading from the ports of aa bad one, or at the very least the programmer would fail to recognize it.Maybe I'm asking for too much.

Bruce, I haven't tried your code yet.I'm afraid your suggestion got buried in the conversation.I think I'll give it a try and post the results later if I have any success.

Thanks for everyone for helping me figure this out.I'm sure I'll have many more questions as I go