On Mon, November 25, 2013 11:55 am, Dwayne Reid wrote:
> The error is that the first location is not programmed correctly
> (desired value (something), read-back value is 00).

When it reads back all zeros- that's usually a sign it isn't getting into
programming/debug mode. #1 tip (see more below)- check the that VPP is
getting through. Try a bulk erase on the part which would clear any
inadvertent copy protect and restore the part to as fresh as possible. The
bulk erase is a separate action in the ICSP world- as close to a complete
wipe as you can get on a PIC.

> I've also tried using the header with a Real-ICE.  I'm not familiar
> with the Real-ICE yet - I've had it only a short while and this is
> the first time that I've used it.  What I did find odd was that the
> Real-ICE doesn't appear to have a Vdd adjustment in the Debugger ->
> Settings menu.

There is no Vdd adjustment with the Real ICE as it does not supply power.
It does need the VDD connection to the circuit- it just isn't a supply
like the ICD2/3 and PICKit2/3.

> Other information: I've tried using both the very short RJ-12 cable
> that came with the Real-ICE with both the Real-ICE and the ICD-2 as
> well as using the longer RJ-12 cable that came with the ICD-2 with
> the ICD-2.  I didn't try the longer cable with the Real-ICE because
> I've read that it probably won't work (length too long).

In situations like this, the thing I try to go back to is the simple
stuff- like are the connections I'm assuming really the connections? Once
you've verified continuity, check that MCLR is changing state as you
expect- including reaching the full voltage.  I've seen many circuits with
too low a pull-up on MCLR which prevents the MCLR voltage from hitting the
threshold to get it into programming mode. 10K is a good value.

Earlier programmers (like the ICD2 and PICKit2 have much stronger (but
less versatile) VPP generators.  It's not as big a deal for older parts,
but some of the newer parts have lower absolute maximum voltages on VPP.
The ICD3 has a better, far more adjustable VPP generator, it just can't
supply as much current.


Matt Bennett
Just outside of Austin, TX
30.51,-97.91

The views I express are my own, not that of my employer, a large
multinational corporation that you are familiar with.
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