RB6 and RB7 both have 4k7 pull down resistors. I just measured it.
Actually I have seen it before from some ICD2 clone circuit.

Xiaofan

-----Original Message-----
From: Philip Pemberton [mailto:philpem@dsl.pipex.com]
Sent: Monday, June 13, 2005 8:01 AM
To: piclist@mit.edu
Subject: Re: [PIC]: ICD2 loading down RB6/RB7?


In message <1118613434.5665.32.camel@pII266>
          Herbert Graf <mailinglist2@farcite.net> wrote:

I'm beginning to think "ICD firmware bug". It uses tristate buffers in th=
e
PGD/PGC circuitry and the 16F877 in the ICD2 has full control over the
output-enable state of the buffers. Setting them to Hi-Z (as it does for
reading data from the chip) should tristate it to the point where all you=
'd
have is normal wire effects (stray inductance, capacitance, signal bounce
and
such).
What I want to know is why the hell the MPLAB 7.11 version of the firmwar=
e
isn't tristating the pins. It sure as hell can do it - the programming
algorithm REQUIRES it (if the buffers couldn't be tristated, you wouldn't=
 be
able to read the program/data memory out of the PIC).

Heck, the ICD2 cost me =A390. I'd expect it to be able to do rapid-cycle
programming... I'll see about filing a problem ticket on support.microchi=
p
in
the morning.

Later.
--=20
Phil.                              | Acorn Risc PC600 Mk3, SA202, 64MB, 6=
GB,
philpem@philpem.me.uk              | ViewFinder, 10BaseT Ethernet, 2-slic=
e,
http://www.philpem.me.uk/          | 48xCD, ARCINv6c IDE, SCSI
... These aren't my boxers -- they bend !
--=20

--=20
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