rtems gdb/insight to jtag

[Erwin Rol]

On Tue, 2004-08-31 at 23:43, Smith, Gene wrote:
> -boggy wrote, On 8/31/2004 3:32 PM:
> 
> > Hello Gene,
> Looking at the "cable" schematic it appears to drive a standard JTAG 
> port as I find on my ppc405gpr (IBM) board. So this should also work 
> with ppc4xx processors too, not just MC6xxx right?
> 

The problem is the spec of the BDM commands, it might electrically be
the same interface, but for example for the MPC82XX you only get the BDM
command+register description under NDA (also useless for open source
projects). The only two MPC it is possible to make OPen Source
interfaces are the 8xx and 5xx. 

> This appears to be a open implementation of the "wiggler" (or possibly 
> "raven") product from Macraigor, right? Curious as to how it differs. I 
> guess it works just as well since Leon P. now say this is what he uses 
> (bdm4gdb==mpcdbm I think).

I believe the open source ones all have the same roots, a few transistor
version by some Russian guy. But they are not exactly the same, for
example the VAS one is a GDB-only path, where i split things up in a
library and a patch. Leon used my version,or tried to use it, since he
helped me find some smaller problems.

> 
> How do you go about programming flash on your target with mpcdbm/gdb?

By uploading code in the shared-onchip memory, and than run that
program, in combination with uploading the data via the BDM port. If the
shared memory is needed for other things (like in a running system) it
will can do the whole thing (slow) via BDM too. The BDI uses JTAG
(wiggling the real pins) i think, so that works for any JTAG supported
CPU.

The next problem is that LPT ports are starting to disappear :-/ So at
some point the interface will be useless. Maybe i will build one with a
EZ-USB or so, but as long as i don't really need to i won't. 

- Erwin
-- 
      Erwin Rol Software Engineering - http://www.erwinrol.com/
tel:+49-(0)8024-479378 gsm:+49-(0)171-6929198 email:info at erwinrol.com