trouble with my 16f84a


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  1. #1
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    Quote Originally Posted by cavity creep View Post
    For this particular PIC at least , it seems to be the norm to use a 47k resistor.
    ???
    Do you mean 4.7K
    Dave
    Always wear safety glasses while programming.

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    Yes I did.Apologies for the typos.

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    Quote Originally Posted by cavity creep View Post
    Yes I did.Apologies for the typos.
    Darn, that probably would have been the problem.

    I do not have an 84A to test your HEX with, but I can say the fuses are correct.
    I do not think it will make a difference, but you may try setting the WatchDogTimer to OFF??
    Dave
    Always wear safety glasses while programming.

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    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

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    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.
    Dave
    Always wear safety glasses while programming.

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    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?

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    Quote Originally Posted by cavity creep View Post
    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.
    Dave
    Always wear safety glasses while programming.

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