gnupic: DIY USB programmer ?
Subject:
Re: DIY USB programmer ?
From:
Byron A Jeff ####@####.####
Date:
8 Jan 2005 03:12:27 +0000
Message-Id: <20050108031224.GB3771@cleon.cc.gatech.edu>
On Fri, Jan 07, 2005 at 06:10:20PM +0100, Manuel Bessler wrote:
> On Thu, Jan 06, 2005 at 08:25:52PM -0500, Byron A Jeff wrote:
> > > I need verify. While the main PIC in my project could do the reporting
> > > back the checksum via RS232, the other boards ("daughterboards") can't
> > > at the moment. There's no 'back' channel. It wasn't designed into the
> > > originals. I have realized that I could need it now, but I can't change
> > > it at this point. Maybe when I do an partial redesign of the
> > > motherboard/daughterboard comms. Right now all the daughterboards do is
> > > receive data and control some outputs according to the received data.
> >
> > Are you planning on integrating the programmer into the main board, or
> > will it be a separate board? From your description I always thought that
> > the process of PIC programming would be a separate activity than using
> > the simulator. So the verify could be a part of the programming board.
> > Or even better you can have the programmed PIC do the verification.
>
> Right now I don't plan to integrate anything on the boards. So a
> standalone programmer.
Good. That's the right move.
>
> > I thought a minute or three today about doing dumb verification.
> > [Snipped]
>
> Maybe I should explain a bit about the topology of my project. Right now
> its a "motherboard" which has a serial port with which it talks to the
> host PC. This motherboard has a 18F452 on it. The PIC has a serial
> bootloader, so this one is easy. Programming once out of circuit and you
> are set.
>
> Now, the daughterboards connect via 4-wires: +5V, GND,
> SerialData,SerialClock.
> The serial line is syncronous (data bit gets clocked in at rising edge
> of SerialClock on the daugherboards). SerialData and SerialClock are
> unidirectional (motherboard -> daughterboards).
> Its a multi-drop bus.
> Daughterboards also use PICs, right now the 28pin 18Fseries PICs like
> 18F242,252,2220,...
>
> Every daugtherboard PIC listens on the serialclock/data lines.
> A simple addressing scheme is used to select the daugherboard. All
> receive it, but if they don't see their own address, the data is
> discarded.
>
> here is the URL to my project:
> http://cockpit.varxec.net/electronics/PHCC.html
>
> > BTW you never stated what parts you are using in your cockpit. Care to share?
>
> Sorry. See above.
>
>
> BTW: I've been using your THVP for the whole project.
Interesting. What software are you using?
>Recently I tried a
> JDM type programmer, but I'm still having issues with it.
> Serial port is a bit less picky about the length of the cable connecting
> the PC with the programmer. Thats why I wanted to try the JDM.
It's one the the reasons I want to get away from the parallel port.
But I'm spending time on this new design because the JDM relies too much
on serial ports being standard for voltages and for syncronization of
modem control signals. I want something that works consistently with
marginal serial ports.
BAJ
