Brand new Promate II
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
- 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.
http://www.piclist.com hint: The PICList is archived three different
ways. See http://www.piclist.com/#archives for details.
See also: www.piclist.com/techref/microchip/devices.htm?key=pic
You must be a member of the
piclist mailing list
(not only a www.piclist.com member) to post to the