Hello to the list.
=20
I am reasonably new to PIC assembler and PICs in general and I have a
question, hoping to get some ideas from the vast experience here on the
list.
=20
Pic 16f84a, 4mhz, 3 7 seg leds driven by PortB,6:0 and triggered by
PortA,2:0.  PortA,3 is count input, High to trigger, and PortA,4 is
Direction indication.
=20
I have written a 16 bit counting program that will perform the =
following
functions:
=20
            Check EEprom and set FF to 00 initially.  This is a one =
time
only process.
            After this is done, EEprom is read at powerup and reset =
time to
display saved values.
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            Second, it will loop, checking and waiting for a pulse =
input on
RA3 to indicate a count of one
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            It will then check for logic level on RA4 to indicate =
direction
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            Finally, during the pulse counting, it will convert for =
display
on 7 seg leds, also updating EEprom .
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Now, the =93problem=94.  When I bring MCLR low to reset the chip, the =
display
will usually show erratic values.  If I power down the test board, it =
will
power up with the usual erratic values, although EEprom holds the =
correct
values.
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I have been checking, but haven=92t found what I might do to ensure =
that PORTB
is =93clean=94 to accept the EEprom values at restart time. =20
=20
Thank you all for your attention and thanks also for the great info =
from all
the contributors on the list.
=20
Mark Cherry
Sacramento, CA

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