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Thread: Brand new Promate II
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face BY : Mike Mansheim email (remove spam text)



> Does anyone know any "magic tricks" to get the Promate II to start
> working reliably?

We use Promate II's for in-circuit programming a lot.  They work very
well most of the time, but we have had to fight through some problems
that sound similar.  So, here's some general thoughts:

- first of all, we don't even use the ICSP module.  We just use the zif
 socket adaptor (AC164012 in our case), and a homemade cable to the
 target board.  During one of the times we were having problems, it was
 decided that the "official" ICSP module was the cure, so we bought one.
 Never did get it to work reliably, and didn't have time to figure out
 why.  So it now lies in a heap in a corner somewhere.  Knowing what we
 learned since, it should probably be looked at again.
- unless you've isolated it somehow, the promate has to supply the 5V
 requirement for the whole board, not just the pic.  We've run into
 problems with target boards with heavier 5V supply requirements.
- related to that, the promate uses a Raychem polyswitch (or similar)
 type of device for current/temp protection that is too conservative in
 our opinion (downstream of the 78xxx regulator).  So we've bypassed it
 on all of our promates.
- I don't know if this applies to your target chip, but we use the F87x
 and find that we have to ground RB3 when in-circuit programming a chip
 that hasn't ever been programmed.  This whole subject has been dicussed
 extensively on the piclist - I can attest that the problem is real.
- a false code protect error is what the promate will give if you try
 programming with nothing attached.  Nearly every time we get a code
 protect error, it is because of a connection problem.  For example, we
 use 8 pin phone jacks for the board interface, and have had problems
 with conformal coating getting in where it doesn't belong and
 interfering with the spring loaded pins.  Also once saw the RB6 pin
 lifted on a surface mount device.  Incidentally, if the device is truly
 code protected, the promate will allow you to go ahead and program
 anyway.
- verify your target board design - we also discovered that we were
 designing our target boards incorrectly.  We were only putting a diode
 between /MCLR and Vdd to  isolate the 5V supply from Vpp.  However, the
 promate (any programmer, actually) needs to hold /MCLR low to reset the
 chip.  Without a resistor in addition to the diode, this shorts the 5V
 supply.  Amazingly, the promate still managed to program these boards.
 Watching the process on a scope showed that the 5V supply drooped
 dramatically, which must have been low enough to get the pic reset -
 seems a nasty  way to treat the promate though!

The two most important things for us were bypassing the promate's internal
protection and paying attention to RB3.

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