Re: Flash Boards

Brian Hechinger wrote ..
> On Fri, Feb 02, 2007 at 02:10:04PM -0500, Mark Gollahon wrote:
> > 
> > You haven't read the history yet, have you?  We've already hashed
> > all of this out a number of times.  JTAG is useless because HP
> > didn't bring the signals out.  USB is useless because its going
> > to be a *host* USB not a *device* USB.  Furthermore, the Jornada
> > cannot be the vehicle by which we put the "first" programming
> > into the flash board (a "chicken-and-egg" problem - see next
> > paragraph).  Finally, reverse engineering the system connector
> > has already been done - that is how I got the information for
> > making a new board....  ;)
> 
> AHHH, you missed what I was talking about.  :)
> 
> I'm not talking about putting any of these things on the Jornada
> itself, but rather the Flash Board itself. :)

Um, that's what I was talking about - these thing on the flash board....

> > Finally, we're left with programming the flash through the only
> > interface we have - the J's system connector.  However, we can't
> > use the J to flash because its dead without its board.  We have
> > to create a specialized flash programmer that acts like a J but
> > that can program the flash.  And creating this programmer is the
> > real time-sink (and why I haven't made this work yet).
> 
> If you've already mapped out the pins on that connector, it should
> mostly be a matter of writing software to frob those pins?  I mean,
> if we had to, we could probably bit-bang the firmware in there, but
> that doesn't meet our expectations of fast. :)

Yes, that is my idea, too.  However you must understand that we will be frobbing 20 address pins, 16 data pins and three or four control pins.  I'm not about to frob 40 pins with a PC.  I was thinking of a USB-connected PIC processor to make the flash board just look like a flash stick.  Then the only software that needs to be written is PIC code (for the programmer, anyway).  But that idea is subject to change as I learn more.

> If I had to money to burn on several Jornadas, I would have purchased a
> Libretto instead.  ;)

Yep.  I agree.  But someone's J is going to have to be the guinea pig.  Since it will probably be mine - I was hoping for "extras" just in case....  :)

Regards,
-Mark Gollahon

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