On Thu, 28 Dec 1995, Martin J. Maney wrote:
>
> Oops, I cut one bit I wanted to inquire about.  You, like others I've
> seen, specify connecting only one each ground and power line to the ZIF
> socket.  The 28 and 40 pin PICs (at least the 73 and 74) have two gounds
> and two each ground and +5 respectively, and I'm wondering if anyone has
> asked Microchip about reccomended wiring for these redundant(?) pins
> during programming of the chips.  I wired the ZIF up to connect both the
> pins for the 16C73s I knew I'd be working with, and it doesn't seem to
> have done any harm, but every time I see someone describe wiring only one
> of each pin for a ZIF socket I wonder about this...

>Also here is what Martin Maney said on the ITU programmer:
>The only problem I had was that the programming would fail after
>writing the first few words until I replaced the 100 ohm resistor
>(R11) with a much smaller value (I used 12 ohms as I had that on
>hand). Perhaps this varies from PIC to PIC, but I had identical
>problems with two 16C73 chips.

I missed this point in my last response.

My programmer has a 100 ohm resistor in line (MCLR) with the 18 pin on
board socket and a 100 ohm resistor in line when my PIGMY board is
used for in-circuit programming via the 10 pin IDC header and the
Load/Run switch. I have only ever programmed the 64 and 84 with it as
I normally use a Newfound PP1 Production Programmer, however Ken
Segler of CyberTech Las Vegas US assures me he has programmed with my
Programmer board and his software, the following PICs without problems:
PIC16C61,C62,C63,C64,C65,C71,C73,C74,C84,C620,C621,and C622.

And the 2 VCCs and 2 Grounds?
Hell, a ground, is a ground, is a ground, I guess! :-))
I have used the pinout to advantage when laying out PCB artwork, apart
from that, I have no idea...

Don McKenzie.            29 Ellesmere Cres., Tullamarine. 3043 Australia
PIC Programmers starting at $15US, BS1/2 & Alternatives 18/28 PIC protos
Promo Disk http://rasi.lr.ttu.ee/~sis/mirror/don/   Ph:Int+613 9338-6286
finger donmck@tbsa.com.au for more info Fax:Int+613 9338-2935 VISA-MC-BC