Date: Mon, 13 Oct 1997 14:10:24 -0700
From: aj pollock <aj_pollock@bc.sympatico.ca>
To: david.tait@uk.ac.man
Subject: PIC16C5X/XX programmer thanks!

Thank you for making available the hardware schematic and the software for
your PIC16C5X/XX programmer.

If you update the documentation for your programmer please consider the
following suggestions.

Do not use a substitute for the 74HC367.  A 74LS367AN would not work for
18 pin PIC's unless a 100nf capacitor was placed between pin 12 and ground.
Even with the capacitor, programmer operation was unstable for both 28
and 18 pin PIC's.

Keep the parallel port cable as short as possible, ie., less than 45 cms.
With a 150 cm long 25 conductor flat ribbon cable the programmer did not
work.  With a 75 cm cable it worked sometimes.  A 45cm cable works always.
Even with a high quality 180 cm IEEE 1284 compliant cable, programmer
operation was unstable.

Finally, never apply or remove power to the programmer with a PIC installed.
Power to all the components of my computer system, including the PIC
programmer, are controlled by a single switch.  During system boot-up the
vdd and vpp LED's come on.  If a PIC is in the programmer during system
boot-up it will be destroyed.  I lost a 16C54/JW and a 16C57/JW doing this!
