Wayne C. Gramlich wrote:
>
>
> Dave (Curtis):
>
> The AT90USBKEY is a neat and inexpensive board.
>
> > On the subject of hosts -- one thing I am excited to play with but
> > haven't had a chance, is the Atmel AT90USBKEY development board.
> > This board is $36 at Digi-Key.
>
> I just checked, it seems to be $31.92 at Digi-Key.

Bonus! Its gone down.

>
> My further comments are:
>
> 1) The AT90USBKey has a AT90UBS-1287 part on it. Since it
> has 128KB of flash, it is not listed as compatible with
> the AVR-Dragon, which is restricted to 32KB of flash.
> It *may* be possible to work on the firsth 32KB of memory,
> but I do not know one way or the other.

That's worth checking. I've heard that the Dragon can debug up to the
first 32K on the larger processors, so you just have to keep your
program under 32K. Which isn't great for bootloaders which are forced to
reside in high memory, but it comes preloaded with a perfectly good
bootloader.

But check for sure before counting on my recollection. And even if it
applies for Mega<large>, it may not apply for AT90USB<large>.

>
> 2) The AT90USBKey is debuggable using the AVR-JTAG-ICE.

Yes, I have one. Wasn't sure if you did.

>
> 3) PORTA through PORTF use .050" x .100" connectors. These
> connectors have two serious problems:
>
> A) It is very hard to find female sockets at that size.

How right you are.

>
> B) The pins are so tight that the PCB design rules usually
> require a manufacturer that can guarantee 5 mil trace
> separation. Most Hobby level PCB manufacturers are at
> 8 or 10 mil trace separation.
>
> I was able to use these connectors once in my life, and
> pain was so great that I convinced the gentleman who
> designed the original board to switch connectors for
> the next board revision.
>
> 4) It is probably possible to side step the connector problem
> by simply soldering in a solid wire.

Which is what I was planning to do. I am planning a card that has the
AT90USB "footprint" on it, and just join the boards as a sandwich using
wires on the 0.050 centers. That should be perfectly doable in 8/8
rules. 0.050 the same spacing as SO, and I get one trace between pads
on SO parts with 8/8 rules.

Another alternative:
http://www.wizbangdesigns.com/10017_PCB.html
$5.95 for a set of 6 header adapters. You end up with 0.100 headers
mounted on little "wings" on your AT90USBKEY. Again, jam in wires to
make a board sandwich.

>
> 5) I really, really want a RoboBrick with USB connectivity,
> working with this board looks like a major project. I'm
> willing to consider the project only if somebody else is
> going to actually help out. This may involve buying an
> AVR JTAG ICE Mk II, designing a daughter board etc.

Well, I already have a design in mind for a board that would mount the
AT90USBKEY as a daughter card. It would have an optional CAN protocol
controller, of course :)

I think the AT90USBKEY is a pretty compelling widget. First of all,
Atmel has priced them very low. For $32, it's hard to beat the
functionality. Secondly, it not only allows your robot to be a USB
device, but since it is USB-OTG you can also use it to host standard USB
peripherals on your robot.

And another interesting looking dev board from Atmel, the DB101:
http://atmel.com/dyn/products/tools_card.asp?family_id=607&family_name=AVR%AE+8%\
2DBit+RISC+&tool_id=4221
$84 at Mouser. 128x64 graphic LCD, a large avr, and a few other widgets,
plus I/O breakout. They are brand new and just trickling out. Mouser
is showing "in stock" -- I pre-ordered one that is somewhere between the
Mouser warehouse and Sunnyvale. I've seen some discussion on the
avrfreaks web site that the DB101 may have some issues -- we'll see when
it gets here.

-dave