If you power OFF your circuit and use LVP then no diode or jumpers are
necessary at all (except the two (or 3) on the portB pins if you are using
them for something else as well - otherwise whatever you have connected to
rb6 or rb7 (or rb3) may become unwantingly active during ICSP programming.
IMHO, you should power off your device before ICSPing it.

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of michael brown
Sent: Friday, 7 February 2003 7:38 am
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: pic16F877 Reset question


On Thursday 06 February 2003 02:26 pm, you wrote:
> The jumper to Vcc is unnecessary really ... you should get into the
> habit of turning power OFF to your board before attempting to program
> it using ICSP. I still, as Wouter has said, do not see the point in
> the Diode in this circuit ??  And this is a simplified ICSP connector
> - there is usually a sixth ICSP connection to RB3/PGM pin (ICSP LOW)
> - rb3 should be LOW during ICSP programming for LVP to work properly.

I sent my other reply before he posted this picture.  I agree that the
diode seems unnecessary since you could just remove a jumper for the
/MCLR pin's Vcc connection also.  I mean, hey, what's one more jumper
if you already have to pull three?  ;-)

michael

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