Lpc2000

--- In lpc2000@yahoogroups.com, Michael Johnson <mpj@r...> wrote:
>

> >
> Debug from reset doesn't work on any LPC2xxx boards we have. If it does 
> work on the chip (which I doubt) then one of the many LPC2xxx board 
> vendors could gain a technical advantage by producing a board that is 
> correctly wired up. Philips don't seem to want to talk about this
area - 
> we asked a long time ago and received a similar answer to yours.
> 
> Regards
> Michael
> 

ARM Application Note 31 talks about debugging directly from RESET, so
it *can* be done. I am just getting started using Phillip's products,
but I used to work for a chip manufacturer that used embedded ARM
cores, and we also had problems with our earlier reference design
circuit boards debugging from RESET. The ARM7TDMI can be debugged
directly from reset, but it does take a correct circuit board and JTAG
pod design to do it since JTAG has to come out of RESET before ARM
comes out of reset accord to AN31. After we reworked our reference
design circuit board hardware, we were able to debug software out of
reset.  That was a really critical necessity at the time, since we had
some write once registers for system configuration that needed to be
written to very early in the normal boot sequence. If they were
written before the debugger got control, it was too late to debug any
difficulties related to that part of the system configuration.

--Dave