[U-Boot-Users] HRCW on mpc8xx

Wolfgang Denk wd at denx.de
Tue Mar 7 00:04:35 CET 2006

In message <af313df20603061432p5dd04d2fq38e1b76ae61cc8b3 at mail.gmail.com> you wrote:
> I have been looking on Readme, Dulg, list and could not find where is
> exactaly the hrcw for 8xx based systems.

Please read the MPC8xx User's Manual. The HRCW is a  hardware  issue.
It cannot be set and not even read (directly) by software.

> Looking at my image (either at the embedded system or the *bin file),
> I've found the magic number (0x27051956) in the begining of it. I
> thought it isn't the hrcw, so, I came around the /cpu/mpc8xx/start.S

No, that's indeed not the HRCW. Not even mine :-)

> So, if the magic number is in the cs0, address zero, it will be at the
> data bus at the reset moment, if CS0 is asserted (better: if the
> device is activated).

No, the HRCW is asserted by external hardware. 

> I do not undestand. Is the magic number the HRCW?

No, it ain't. To most people it's just a magic number.

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
Things that try to look like things often do look  more  like  things
than things. Well-known fact.       - Terry Pratchett, _Wyrd Sisters_

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