The problem

I've pretty much run out of ideas as to why I can't seem to get a program
to run in a 17C756 device.  I designed a board around a 756 and can't get
even the simplest program to run.  I decided it was just as easy to
prototype the board and test since this is a 68 pin PLCC package and I
didn't have any adaptor for breadboarding it.  I have since designed and
built an adaptor and am having the same trouble.

I have tried the device in Xtal and RC mode.  In RC mode, i see a 1 Mhz
sawtooth signal on OSC1 varying between 1.5 and 3 volts approx.  OSC2
remains at ground so I am pretty sure it doesn't matter what I program, the
chip isn't running.

Qualifications

I have designed and built several projects using a variety of PIC
processors of the 14 and 16 bit cores but this is the first in the 68 pin
package.  I have the latest MPLAB software and firmware in my picstart and
the device seems to program correctly.  I have four actual parts so im not
suspecting a bad part.  I belive I have tied all of the VDD and VSS pins
correctly, and have MCLR tied high and the test pin tied to ground.
However, the fact remains that it doesnt work, so I am assuming I am doing
something pretty fundamental wrong.

Measuring the ports shows that all of the PORTB pins to be pulled high, and
all other port pins look like they are floating near ground.

Even though I don't belive the program is an issue, i will append it here
anyway.

        LIST   P=PIC17C756, R=DEC

        __CONFIG _WDT_OFF & _RC_OSC & _BODEN_OFF & _MC_MODE
        #include "P17C756.inc"

        cblock  0x0020
                TEMPCNT
        endc

        org     0x0                     ;reset vector
        goto    start                   ;goto start of program

        org     0x0008                  ;RA0/INT irq on RA0 vector
        goto    extirq

        org     0x0010                  ;TMR0 overflow irq vector
        goto    tmr0irq

        org     0x0018                  ;RB1/T0CKI irq vector
        goto    t0ckiirq

        org     0x0020                  ;peripheral irq vector
        goto    periqr

        org     0x0030                  ;start of program memory

start
        bsf     CPUSTA,GLINTD           ;disable all interrupts
        movlb   0                       ;select bank 0
        movlw   B'00000000'             ;set data direction
        movwf   DDRB                    ;set portb data direction register, bank
 0
        movlw   B'10101010'             ;set port values
        movwf   PORTB                   ;set initial port values for any outputs
        bcf     PORTA,NOT_RBPU  ;enable weak pullup resistors

loop
        incf    TEMPCNT,f
        movfp   TEMPCNT,PORTB
        goto    loop
tmr0irq
extirq
t0ckiirq
periqr
        retfie                          ;ignore unused irq's

sreset
        goto    start                   ;software program reset

        org     0x0FFF                  ;last program location
        goto    sreset                  ;perform software reset

        end
Thanks!

Bob Bullock
KoolKits