[U-Boot] BDIxxxx and others...

[David Hawkins <dwh@ovro.caltech.edu>]

> I see you guys talking about BDI3000 and I decided to ask a related
> question.
> 
> Those who happen to own MPC8548CDS or something like this know it comes with
> a small box called CodeWarrior USB TAP.
> 
> It is supposed to work with their software one has to pay for. I never used
> anything but GCC suite for anything GCC supports and always tried to avoid
> commercial tools like a plague. So I want to ask if somebody knows if there
> are any free tools for that thing...
> 
> Not that I really need it for something but it is sitting in the box
> gathering dust and it would be nice ot somehow put it to do something...

I've wondered the same thing. But didn't manage to find
anything out there. I've got three ... in the boxes
the Freescale MDS boards came in.

The USB-TAP has a PowerPC processor in it ... so even if you
had to blow away the original firmware, I'm sure it wouldn't
be too hard to figure out what code would be required to
make the device look like a USB debugger, and then create
a set of USB commands to generate JTAG transactions.

I think the main problem is getting the JTAG TAP codes
for manipulating JTAG. I've never seen a document relating
to that, so they are obviously NDA.

That being said, a weekend with a logic analyzer on a
BDI2000 JTAG connection would probably give you all the
info you need to figure out the appropriate JTAG
commands.

I've wired up the COP connection on my board via an FPGA,
so that I could conceivably use the PowerPC JTAG via
PCI. However, its the lack of open documentation on the
JTAG commands that has limited my interest in pursuing
this. However, it would be simple to use that interface
to log all JTAG transactions, to figure out all the
JTAG TAP instructions.

Cheers,
Dave