Hi Jim,

Basically it's a box that plugs into a PC parallel port and works with any
of the usual AN589-style programming utilities, such as prog84 and jpp877.
A 5-pin connector goes out to the circuit being programmed, and carries
power (3.3 or 5.0V selectable), ground, MCLR/Vpp, and the programming clock
and data lines (RB6/PGC and RB7/PGD for the '84). The PGC and PGD lines
also double as TTL-level RS232 tx/rx lines if desired (the box is smart
enough to disable the transceiver during a program operation). This I/O
goes out to a serial connector on the box for connection to your favorite
terminal.

If the circuit to be programmed is going to use its own power supply, all
you have to do is endure there's a diode between the PIC and your circuit's
reset circuitry, to protect it from the ~13V Vpp during programming. You
also have to be careful about what you're using RB6 and RB7 for, as
discussed in the ICSP guide from Microchip.

If the circuit to be programmed is going to use power supplied by the
programmer, care must be taken to ensure that it doesn't draw too much
power (unspecified right now but probably somewhere around 800mA). The
first board I designed to interface with this programmer (a serially-driven
graphics LCD controller) has a split supply: one small SMT regulator powers
the PIC, one big TO-220 regulator powers the rest of the circuit. This
greatly simplifies the process since the programmer only has to power up
the PIC and can ignore the rest of the circuit if it's properly isolated.

As for software on the PIC, there really is none required. The "debugging"
feature I mentioned refers to the hidden ability to send serial data to and
from the PIC firmware while it's being developed, so you can insert tx
commands at strategic points to let you see what the thing is doing. I
don't know how useful this will be to anyone else, but I personally use
this trick a lot.

Anyway, it seems to be a quite useful little device, and is almost as cool
as an ICE if you factor in the order of magnitude cost reduction. :)  No
real new technology here, just an interesting subset of various
presently-available development tools.

mcb



At 02:58 PM 9/12/99 -0500, Jim Paul wrote:
>Matt,
>
>I would be interested in at least looking at it.  If you could detail some
>of the functionality,
>that would help.   What I'm  talking about here is specifically what does
>the debugging
>portion of it do for me and how does it do it?  Do you need any code above
>the application
>firmware in the target device to use the debugging portion of it, or do you
>need anything
>beyond that?  Let me know as I'm always in the market for development tools
>for PIC's.

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     Matt Burch      |  Pinnacle Technology   | tel: (785) 832-8866
  Project Engineer   | 619 E. 8th St. Suite D | fax: (785) 749-9214
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