Here's some more info on my problem... Any suggestions would be appreciated.
It seems that the oscillator is running fine, VDD is at 3.3V, but the weak
pull-ups are not enabled on PortB.  This is a problem as far as decoding
inputs, but there is something else wrong that will not allow basic
execution of the code.  PortA should have a flashing LED, but nothing.
There must be something going on in the fuses or ICSP procedure.  I just
can't find what I'm missing.

    Here's my complier config:
 __CONFIG _CP_ALL &_PWRTE_ON & _WDT_OFF & _XT_OSC

    And my Option setup:
OPTSET  EQU     B'01000110'     ;OPTION-REGISTER SETUP.

    And PORTA setup:
    SETPA   EQU   B'11110000'      ;PORTA I/O STRUCTURE.
    INITA   EQU   B'00000001'       ;INITIAL STATE OF PORTA OUTPUTS.
  MOVLW   INITA           ;INITIALIZE THE PORTA OUTPUTS.
  MOVWF   PORTA
  MOVLW   SETPA           ;SETUP PORTA'S DATA DIRECTION REGISTER.
  TRIS    PORTA

    And PORTB:
INITB   EQU   B'00000000'       ;INITIAL STATE OF PORTB OUTPUTS.
SETPB   EQU   B'00111111'       ;Redefine PORTB I/O STRUCTURE.
etc...

    It runs beautifully w/my ICE, as well as on any board w/ an 'F84; but
not on any board w/a 'C621A.

    Thanks,

    Tim
    -----Original Message-----
From:
Sent: Wednesday, January 24, 2001 1:00 PM
To: pic microcontroller discussion list
Subject: [PIC]: 16C621A vs. 16F84


Dear Piclist:

    I have a problem using 16C621 A  parts.   I finished development w/
F84's now I'm converting to the '621 and checking out the code.  I added a
step to set the CMCON register to 0x05 (all digital  comparators).  It works
great with my emulator (ICE2000 w/ PCM16XC0), but when I program them
individually, they seem to get stuck somewhere after initialization of RAM,
ports and option register and before the main code.

    Any thoughts?

    Thanks,

    Tim Crist
    Tri-tronics

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