gnupic: DIY USB programmer ?
Subject:
Re: DIY USB programmer ?
From:
David Willmore ####@####.####
Date:
11 Jan 2005 21:41:49 +0000
Message-Id: <200501111805.j0BI5ddK031515@localhost.localdomain>
> > I wouldn't count on this chip being available for much longer. IIRC, it
> > was a 12V FLASH power supply chip and those kinds of FLASH are long gone.
> > This chip can't be hanging around much longer, either.
> There exist replacement chips. As example microchips sells one.
> The chips now are used for powering audio op/amps, rf stages, leds.
Good point. Still, it's not a very high volume chip and would be abandoned
by suppliers if volume fell or if a better solution (for their problem)
came about. I wouldn't place much trust in it's long term availability.
> > If you use a design like Wouter's for the HV, not only do you not need
> > another chip, but you can tap off of it and feed that back (via a
> > resistive
> > divider) into an analog input of the uC. That way you can use a variety
> > of Vpp voltages.
> The disadvantage is, that you are limited on the chip types. With a simple
> voltage tripler, only the most flash types are programmable.
> The chip version has more output power and minor ripple.
Sure, a capacitor based trippler won't be able to supply much current. Maybe
I need to go to a boost based design?
> > I would say make a decision. Either you want a bootstrap programmer--in
> > which
> > case don't use sockets, have the target in a breadboard and use a few
> > loose
> > wires to connect programmer to target. Or, you want a more full featured
> > programmer in which case you *want* a ZIF socket. Given that the smallest
> > USB PIC is a 28 pin part, you have I/O to use in routing to more pins on
> > the ZIF socket.
> >
> Routing mean, vpp routing and vss/vdd (100 mA).
A few PNP transistors or P-channel FETs. No big issue.
> > That's a good question and I haven't looked into it. Does anyone have any
> > more
> > information on this? Is there some orginization which has already
> > purchased
> > a VID and will sell PIDs?
> The cheapest offer was 250$ for one pid/vid.
Hmmm, where did you find that--feel free to send it directly if it's not
a public offer.
> > With their programmers, IIRC, you're stuck with their programming
> > software,
> > right? Ich spreche leider kein Windows. No se hable Windows.
> The Sw protocol is open. I have downloaded from internet the linux sw to
> program
> pic and scenix cpu's using this usb devices. It was a modification of the
> linux
> software from the newfound warp13 programmer.
Ahh, okay, last I looked at their pages, I saw no reference to the protocol
being available. Could you point me to it?
> > If you do that, you need more I/O or you need to do something ugly with
> > the
> > socket. Also, you need that extra "not long for this early" 12V supply
> > chip. It solves one problem and creates another. Now your programmer
> > must use specialized programming software, as well.
> The 18F parts, that are able to sw flash programming can disable the low
> voltage
> programming option without needing a high voltage programming.
Right, but if the programmer is supposed to become a more general purpose
programmer after it's bootstrapped, you'll need the HV supply later for
the other chips you want to program.
> > > The kitrus kit costs 26$ in quantity 100 and it has active routing, but
> > only
> > > a voltage triplier, so one need really a 5V USB +-4%. Generally, this is
> > not
> > > a problem.
> >
> > It's an open design? What software does it use?
> >
> Schematic are provided, including open protocol and hex firmware.
> It uses the serial FTDI and a 16f628 or 16f648.
Interesting.
Cheers,
David
