Harishankkar wrote:
> Hi ,
>
> Thanx. Okay Strong ARM cannot do it. But my general doubt is that is it
> possible to access core registers of any processor via JTAG ?. I am talking
> in reference how using the freeze pin of the MPC 823E or the Power PC series
> we can get the values of the internal registers etc. Is it a JTAG interface
> like thing?
Tuning into this rather late... Some ARM architecture processors have JTAG
access
to internal registers, co-processor registers etc. Some do not. The XScale,
Intel's
'Strong ARM 2' has JTAG support for so called emulators. Athough these days
the emulator really could be better described as JTAG debug control devices.
In addition to the primitive control of the JTAG signals, usually one needs some
set of software to allow 'easy' access to the controllable features of the chip.
This
varies from vendor to ventor. In addition, some JTAG hardware suppliers have
several software vendors which provide varying degrees of control and
capabilities.
The summation is, what JTAG support is available is highly variable. If you are
working with an SA-1110 design, then there may be next to nothing. In the case
of the XScale, there are at least 4 JTAG hardware interface device vendors, and
some set of software vendors which support such devices.
As for other ARM architectures, since my design is XScale, I have not needed
to look in more depth. But I'm sure many chips designed in the last 2-3 years
will have some form of JTAG control capability for debug purposes... if not
find a chip vendor and architecture that does...
In addition to controlling the processor register set... I suggest one function
for the JTAG package be the ability to program the on board flash devices,
if there is no hardware provision for a socketed programable device...
_______________________________________________
http://lists.arm.linux.org.uk/mailman/listinfo/linux-arm
http://www.arm.linux.org.uk/armlinux/mailinglists.php
Please visit the above addresses for information on this list.
