Re: Flash Boards

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. :)

> 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. :)

> I'd LOVE it if you could do that piece.  However, making the
> board AND programmer must come before RedBoot and eCos.  There
> are a few things you can do in parallel (like getting
> RedBoot's RAM version running on the J), but we will still need
> a ROM version to put into the flash and that step can only be
> done once the hardware has been manufactured.

Obviously. :)  A RAM implementation wouldn't be a bad first step as
it would be a bit easier to learn how to access all the hardware
directly without having to reflash the blasted thing all the time. :)

> So far I've counted somewhere in the neighborhood of 20 boards for
> the community.  This means a minimum of two batches of boards - 5
> in the first batch as development "you can torch these boards", and
> 20 in the second batch for the community once the development is
> done.  Not a large number , but nothing "to sneeze at" either.  Now,
> if I could buy a couple of J's from Buy.com so that I can blow them
> up, too.  :)

20 is a nice number.  should get an ok rate on the final run of boards.

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

-brian
-- 
"The reason I don't use Gnome: every single other window manager I know of is
very powerfully extensible, where you can switch actions to different mouse
buttons. Guess which one is not, because it might confuse the poor users?
Here's a hint: it's not the small and fast one."        --Linus