[U-Boot-Users] about the system clock config

[Wolfgang Denk]

Hello,

in message <55113502b9.502b955113 at rails.com.cn> you wrote:
>
>     I have configed my WindRiver mdppro8xx board
> according to the  TQM8xxL module.The outcome is :

This makes little sense unless you know EXACTLY what you're  doing  -
and  in  this case you usually will start with a new config file from
scratch.

> Now I want to set my system clock to 50MHz.

Do you know exactly how the clock  systems  are  implemented  on  the
TQM8xxL hardware, and on your board?

What makes you think that the TQM8xxL is so similar to your  hardware
that you can just copy the configuration and expect it would work?


>  so I added these:#define CONFIG_80/66/50MHz,but the
> outcome are still :
> ________________
> CPU:   XPC823xxZTnnB2 at 25 MHz: 2 kB I-Cache 1 kB

This is obviously because you are on differetn hardware,  which  uses
not the same input clocks as the TQM8xxL.

> Why  did my #define CONFIG_80/66/50MHz not work?

Because your hardware is different.

> board.h,right? So where to modify my system clock to
> 50MHz?:-)

Start reading the schematics of  your  board.  The  read  the  MPC860
User's  Manual.  Pay special attention to Chapter 15 Clocks and Power
Control. Go through Figure 15-1 step  by  step  and  wrtie  down  all
initialization  values  (MF  bits, PLPRCR, SCCR, ...) needed for your
hardware configuration. Then check where those values are set in  the
config file. Enter the correct values. Then try again.

I am afraid I cannot save you the  effort  of  performing  all  these
boring steps, but without in-depth understanding of what you're doing
you will not succeed.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
Without freedom of choice there is no creativity.
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