Dmitry Mastykin wrote:
> I suppose that it's because of some peripherials settings.
> Can you advise me which LPC2148 registers could influence to this?

JTAG is entirely independant of the microcontrollers peripherals and
registers. It is a vary simple interface. Moreover its clock rate is
entirely determined by the host not the target. So I would suggest that
it is a host problem.


> Can you also explain to me why debugger must program the
> microcontroller. Can I program it before, and then run debugger without
> "load" command?
>
Yes, you can do that. The code (or at least the symbol table) must have
been loaded to the debugger so that it can provide source level
debugging. That symbol table must also match exactly the code on the
target, so if you rebuild the code, you must reload the target. But yes
you can simply connect to a target and debug the existing code. If the
code is in ROM you cannot set software breakpoints, only hardware
breakpoints, and these are a severely limited resource (usually just
two). Also if you are debugging code that is copied from ROM to RAM
during boot-up, you must set a hardware breakpoint at some point after
the code has been copied, this then allows any software breakpoints to
be applied (as the copy to RAM will have overwritten them otherwise).

Clifford

Clifford Slocombe wrote:
> JTAG is entirely independant of the microcontrollers peripherals and
> registers. It is a vary simple interface. Moreover its clock rate is
> entirely determined by the host not the target. So I would suggest that
> it is a host problem.
>
Thank you very much for the answer! I think, I will not use "load"
command for the present. But for me it's strange, how may loading of
simple LPC2148Test program may be so healing for the host, so that the
rate of following loading of my project increases ten times, up to
3kB/s.

Dmitry

I have no idea, and have not used this device, or OpenOCD. I would
suggest putting a scope on the TCK line to see what rate it is achieving
and whether it is intermittent.