Re: Hardware debuggers for PPC74xx G4 CPUs

On 11/22/07, Benjamin Herrenschmidt [off-list ref] wrote:

On Thu, 2007-11-22 at 19:00 -0500, Jon Smirl wrote:

quoted

quoted

It seems like AMCC does provide the necessary infos for 4xx

processors

quoted

though. Jon, do you think what they provide is enough to use an open
source debugger ?

Do you have a link to the info?

Not at hand, but easy to find from AMCC main product page, you can then
go to the various eval board download pages, and some of the d/l are
infos for JTAG debugger manufacturers.

Dominick Rath wrote OpenOCD (open source JTAG) as his senior thesis in
college, he graduated this spring and has a job now. I've sent mail to
him but he may be a lost cause.
Thesis: http://developer.berlios.de/docman/display_doc.php?docid=1367&group_id=4148

Low cost dev tools are an important part of the CPU selection process.
We went through four ARM CPUs before deciding on the MPC5200. We were
able to get ARM eval boards and JTAGs for under $500 for each of the
eval CPUs. We used the low cost evals to screen the CPUs, we didn't
want spend $5-10K until we are 90% sure we are going to use the CPU. I
returned one $5K eval board, it was a pain and it took over six months
to get a refund.

We have also learned the hard way about "port and forget" several of
the CPUs we picked had Linux ports, but the ports were five years old.
When we pushed the vendors for more recent kernels the typical answer
was, send us $50,000 and we'll see what we can do. We're not going to
send in $50K for a CPU we haven't decided to use, that answer simply
resulted in us changing CPUs. An example of this is the NXP LPC3180,
$9 with a FPU, but only a 2.6.5 kernel.

I've also only seen ARM CPUs being used in schools. You can get ARM
eval boards and a JTAG for under $100 on some ARM CPUs. AFAIK there is
no low cost PowerPC option suitable for classroom use.

-- 
Jon Smirl
jonsmirl@gmail.com