[U-Boot-Users] BDI2000 vs Vision-ICE

Wolfgang Denk wd at denx.de
Fri Jan 9 00:04:38 CET 2004

Dear Mike,

in message <3FFDC547.3010302 at lucent.com> you wrote:
> People at my place of work are telling me that the
> Vision-Ice supports "backtrace" and the BDI2000 does
> not.   I looked on the Abatron website and it doesn't
> say.  Can anyone confirm or deny this?
> By "backtrace", I mean the ability to set a breakpoint,
> hit that breakpoint, and be able to see the last N
> instructions executed.

I don't know about the Vision-Ice; but  I've  been  working  (several
years  ago) in a project were we spent a lot of $$$ to buy a SuperTAP
ICE by  Applied  Microsystems  exactly  because  they  promised  this
feature.  It  never  worked  for us. It didn't work at full processor
speed, and the problems where we really wanted a trace did  not  show
up  at  lower  clock  speeds.  The other setup used a MPC8xx with bus
divider  enabled  (CPU  clock  =  2  x  bus  clock).  With   such   a
configuration,  the  CPU does not output the signals you need for the
trace on any pins, so you cannot  get  any  trace  (no  matter  which
vendor's box you buy).

In my experience, this is marketing babble. For the low  level  stuff
("simple  problems"),  a  good logic analyzer is at least as capable,
and for  the  highlevel  ("complicated")  problems  it  doesn't  work
anyway,  and  a plain BDM/JTAG debugger plus a little brain and a lot
of experience gives beter results.

Just my $ 0.02 - ymmv.

Best regards,

Wolfgang Denk

See us @ Embedded World, Nuremberg, Feb 17 - 19,  Hall 12.0 Booth 440
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
By the way, ALL software projects are done by iterative  prototyping.
Some companies call their prototypes "releases", that's all.

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