gnupic: DIY USB programmer ?
Subject:
Re: DIY USB programmer ?
From:
Manuel Bessler ####@####.####
Date:
5 Jan 2005 01:27:43 +0000
Message-Id: <20050105022047.C19450@betazed3.varxec.de>
Hi David,
On Tue, Jan 04, 2005 at 01:13:48PM -0500, David Willmore wrote:
> Buying a preprogrammed PIC from someone is probably a bit easier than
> getting one of the FTDI chips and it's certainly easier than *working*
Yes, true, but I've had one fellow who went to a place where he got the
PIC programmed, but that wasn't cheap. And my designs consists of different
boards, and some types of them need PICs. So the cost would add up
quickly, esp when I do updates (for those boards that don't have
bootloading capability yet).
> with them. If you're afraid of getting a PIC programmed SMT soldering
> probably isn't your thing, either. :)
Believe it or not, one guy has way more trouble with PIC burning than
SMT soldering (and it was his first SMT).
> > I've skimmed the programming specs for two chips, and it looked like
> > most timings don't have a "max" defined. So, would this be possible ?
>
> Possible or useful?
More like useful.
> > What do you guys think ? Could it be possible to build a simple burner
> > that does not need "intelligence" apart from an USB interface chip.
>
> I just don't see the benefit.
Same as JDM does for owners of serial ports :)
Simplicity, cost, availablility.
> > I know the FTDI USB chips have a "bit-bang mode".
>
> Yes, and there are some drivers for it, but I've heard of issues with
> people who have used it in that it still does not preserve the timing
> as they expected it to.
Thats why I was wondering about the max timing values...
> > Your opinions please :)
>
> I'm a bit biased as I'm working on a USB PIC (well, doesn't just have
> to be PICs) programmer. It will likely be just one PIC18F2550 or
> '2455 with some fairly simple external parts--transistors, resistors,
> caps, and diodes. Mostly junk box variety parts. If you squint your
> eyes *real hard*, it may look like a Wisp628, but that would be a bit
> of an illusion.
This sounds cool.
What you describe, I was wondering if something like that existed.
If I have to go the "intelligent" programmer route, this would be the
best alternative.
I've actually thought about this myself, but, as I said in my other
post, its a matter of time. It takes time to develop and to maintain.
As a matter of fact, I wondered if it would be possible to
"parameterize" the burning protocols such that there wouldn't be any
changes necessary in the burder-PIC itself.
And the new USB flash PICs would be a great way for this. I even have
two 18F2550's here :)
> To the computer, it will look like an USB->RS232 'dongle', so most
This is even better. Excellent idea. I'm looking forward to your design.
Will it be free/open source ?
Please keep me posted on your programmer project.
Regards,
Manuel
--
Opensource/Free Software: No Gates, No Windows
