[U-Boot-Users] Setting up reset on the EP885C

Wolfgang Denk wd at denx.de
Tue Jul 12 22:20:50 CEST 2005

In message <loom.20050712T193709-463 at post.gmane.org> you wrote:
>  However, when I try to run from 0xFC000000 or 0xFC000100 I get no display at
> all, and the BDM reads -TARGET: STOPPED.  Also, when I try to just program to
> flash and then reset the board it seems as if no code is executing.

Don't try to run any code from any specific address at all.  Let  the
CPU  do what it wants to do. Force a reset, and then just single step
in your debugger. I would be surprised if the CPU would not start  at
either 0x0100 or 0xFFF0100.

> Can anyone verify that 0xFC000000 is the correct flash location for an EP885C? 

It is as good as any other. You can map the flash basicly  everywhere
and get a working system.

> Also, I am thinking that by resetting the hard reset configuration word, I could

Oops? I cannot parse that. Reset the HRCW? What exactly do you mean?

> force the board to jump to the correct instruction location, but I am at a loss
> to figure out how to change the hrcw's value.  Any help would be greatly

The HRCW is something you (resp. your hadrware) applies to the bus at
reset. Study the schematics of your hw - this might be as  simple  as
pull-ups  or  -downs  (if  your  hw  is  half-broken),  or  some more
sophisticated way to drive  a  certain  value  on  the  bus  in  this
situation.  Unless  you  use some prgrammable device fort his purpose
you cannot "reset" the HRCW - and if you can change it, it will  take
effect  only  at  the next reset. It will definitely not make the CPU
"jump to the correct instruction location".

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Any sufficiently advanced technology is indistinguishable from magic.
Clarke's Third Law       - _Profiles of the Future_ (1962; rev. 1973)
                  ``Hazards of Prophecy: The Failure of Imagination''

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