gnupic: DIY USB programmer ?
Subject:
Re: DIY USB programmer ?
From:
Byron A Jeff ####@####.####
Date:
14 Jan 2005 00:28:36 +0000
Message-Id: <20050114002832.GA1389@cleon.cc.gatech.edu>
On Thu, Jan 13, 2005 at 01:43:48PM -0500, David Willmore wrote:
> > > Exactly. The 556 can be used in two places in the circuit--once for the
> > > bootstrapper and once in a HV power supply switcher. That keeps the
> > > micro from having to walk, chew gum, pat its head and rub its belly all
> > > at once. ;)
> >
> > You'll have to change up some parts to get it going as I'm sure that the
> > frequency for the HV will have to be higher than the delays for the
> > monostables.
>
> I was thinking of having two different places on the board for the chip to
> fit in. It would cost one socket, but the bootstrap 'option' for the kit
> would be the socket for the 556; an E9 shell; and the handful of caps,
> resistors, and diodes. From a company that just sells boards and simple
> kit parts, they can sell it with the bootstrap option--as they are unlikely
> to have PIC programming ability. But places that can program the PIC will
> just not supply the 'bootstrap' parts.
OK. That's fine with me.
>
> For those who just want to build the think from digikey parts,
Radio Shack David. The US gold standard is parts from the RatShack parts
drawers as expensive as they may be.
> they can so
> with just a bare board--buying the bootstrap parts themselves.
That's cool too.
>
> So, don't worry about the circuit around the 556, we'll move the whole
> chip. :)
Ah. Understood.
>
> > I took a 5 minute look at Pikdev. It'll require adding a new type of
> > programmer
Port, not programmer.
> > separate from the parallel and serial programmers defined now. Fortunately
> > the class only has a handful of definitions. I didn't see how to connect
> > the type to the class though.
I found it. A new port is instantiated in hardware.cc. I got a failure of
pkp when I set the type=555 in .pkprc. So it's just a line of code.
> > It should be too difficult to pull off.
Misspoke: It should NOT be too difficult to pull off.
>
> I thought it would fit in pretty easily. You'd need to make a new
> programmer
> dialog for it, but it would only have to have a pulldown for serial port
> as an
> option--maybe we'd need some calibration stuff in there too, huh?
I'll leave that up to Alain to decide the interface. I'll do all of my
testing using pkp and the .pkprc file from the command line.
>
> > I think I'm going to adopt pikdev for my programmers since it has 18F
> >support and works with the Trivial programmers.
>
> I've been using it for use with your THVP for a while now and I've had great
> luck. For those PICs that it didn't support, I found that it wasn't that
> hard to add it. Of course, I have to finish submitting that... Sorry
> Alain...
I happy to find out that it works. Is there a Windows port for pikdev. I
didn't see anything for it in the download section.
>
> > > :) Well, for my part, I'm going to try to finish up some Pikdev chip
> > > support code (sorry Alain) and watch Byron work his magic! :)
> >
> > I hope to get a chance to work on it some more between now and the weekend.
> > I'm continuing to think on the verify problem that I outlined in my
> > preliminary results post. I realize that I need to isolate the PIC Program
> > Data pin from both the incoming TX circuit (which I was going to do anyway)
> > and the outgoing RX circuit. So it'll take a couple more transistors.
>
> NPNs if they don't have any special requirements are damn near free, so don't
> feel bad. Just follow these kit building guidelines: If you have to use an
> expensive part, use it. If you can avoid it by using a few common parts,
> do so. If you've already used a part using it again is fine.
Then I'm in pretty good shape.
>
> Having 'kitted' a few hundred kits, can safely say that the worst kits to
> prepare are the analog ones where you have *one* of this odd value, *one*
> of that, *one* of some other identical value, but 1% tolerance, etc. I love
> digital designs that are like "C1-C50 .1uF momo cap, R1-R18 10K 5% 1/8W,
> R19-R40 1K 5% 1/8W" Woooo Hooo! That's three parts as I count them. :)
Understood. I think I'll need 3 resistor values along with the pots.
There are two cap values. I'll have to have the zener and a regular
signal diode. And of course the sprinking of NPNs along with the 556 itself
which could be implemented with 2 555s in a pinch.
But it's a handful of cheap plentiful parts.
>
> > I'm starting to think that a modular design may be possible without too
> > much effort. That way you can build the design with or without
> > verification.
>
> I'm always leary of capacitors as they have the largest tolerance specs of
> any common electrical part. Resistors you can get in any arbitrary tolerance.
> Inductors tend to be available in better than 10% tolerances. But caps,
> sheesh. Common 'lytics are +70%/-20% tolerance! Do a timing circuit with
> them, not without calibration. Now, expensive mylar caps can be 1%, but
> they're hard to find and they're not cheap.
That's why I planned on having the pots for tuning the timers.
What's the typical tolerances on tantulums?
>
> That's just my take on kitting. Maybe someone else does it differently--and
> they'd like to interject with their design guidelines.... :)
>
> Keep up the good work, Byron!
I'm very interested now because I can see the light at the end of the tunnel.
The bootstrapper will serve all of my immediate needs because once it's
coupled with pikdev I'll be able to program all the 18F chips that I've
been sampling along with the 12F parts that I've been drooling over. I'll
finally retire Brian Lane's picprog that I've been helping limp along for
the last few years.
BAJ
