I believe that the correct programming voltage (Vihh) on MCLR is
meant to be nominally +12 volts.

I could not find the actual specified value anywhere in the 16F84
data sheet.
In AN589 microchp themselves use 13.5 volt. This is for a 16C84 but I
believe the voltage is the same for each. AN656 uses 13 volts.

Your reported 9.4 volts sounds MUCH too low - is this due to a low
supply voltage or does the voltage at MCLR drop to this level during
programming? - if so you may wish to look at other causes.


-----Original Message-----
From: Lynx {Glenn Jones} <jones_gl@EFN.ORG>
To: PICLIST@MITVMA.MIT.EDU <PICLIST@MITVMA.MIT.EDU>
Date: Thursday, September 10, 1998 6:30 PM
Subject: PIC-Programmer 2 not working


>Has anyone built the serial pic programmer at
>http://www.gbar.dtu.dk/~c888600/newpics.htm   ?
>I just finished, and despite checking, rechecking and other efforts,
it
>wont work. I measure 5.25 Volts across Vss and Vdd and 9.4 Volts
across
>MCLR and Vss. is this not enough? also, Ive tried several softwares
>including the one that is on the site to no avail. it seems unable
to read
>or write, when i try reading with a PIC in, i get a bunch of 3FFF's
and i
>get exactly the same without the PIC. Im using a PIC16F84. I have
tried
>two different chips with no success. any ideas?
>
>
>--------------------------------------------------------------------
----------
>A member of the PI-100 Club:
>3.1415926535897932384626433832795028841971693993751
>058209749445923078164062862089986280348253421170679
>