Stewart:

You realy must connect those pins together and to supply.  I accidentally left
one of the VS's off on a '73 once, and the A/D didn't work right at all.  A
cursory check with a meter saw that pin at ground, or so one would think on a
quick glance.  Turns out that a few tens of mV will whack the A/D.  Connect
them through and to supply, with bypass.

Try a small hello world by killing the watchdog, interrupts, and all
unnecessary calls.  Start small and work up!  You might just read TMR0 and
stuff it onto port C for the fun of it.. Scope should go nuts.  Don't forget
that the portA is set for analog function by default.  Ref ADCON0/1.  And that
RA4 is an open collector all the time.  If you were looking for excitement on
one of these RA pins, you could have the wool over your eyes.

Stewart Pye wrote:

> Hi...
>
> I'm testing a project that uses a 16C74A. I've used the 16F84 quite a bit
> but this is my first try using the 16C74 with a HS osc at 16Mhz.
>
> Problem:
> I cant even get an led to flash. I know the code is correct. I set the osc
> to HS.
>
> Question:
> Are the two VDD and VSS pins connected internally???
> I got 12ohms between the 2 Vss pins but several Mohms between the Vdd pins.
> Is this correct??
> Should I connect these pins externally???
> Is there something else that could be causing the problem?
>
> Any help would be much appreciated. (the frustration's building)
>
> Thanks,
> Stewart Pye