[U-Boot-Users] A question about sdram_init

Wolfgang Denk wd at denx.de
Fri May 14 09:35:06 CEST 2004

In message <BAY2-F138np7Y5pnryM00015182 at hotmail.com> you wrote:
> OK, the system I am using is PPC405 custom board. The board is same as 
> WALNUT but install a special purpose I/F in ASIC. That's why I said it is 
> similiar as WALNUT. Since that part won't interfere others, it can be 
> considered same as WALNUT. The board has 8M bytes SDRAM installed. SDRAM 

Does it use exactly the same RAM chips as the walnut?

> I know. But my boss keep saying learnning to use the debugger is 
> time-consuming and refused to buy a debugger for me, which really pissed me 

Your boss is of course right. Learning  how  to  use  a  debugger  is

Maybe nobody told him that working without a debugger  is  even  more
time-consuming, and he will lose this time again and again, while the
learning part is needed only once.

> off. Sigh... But this is the reality - I don't have a debugger and have to 
> have to have the u-boot run on my system within one week...

This is probably where he "hire a guru" part  of  the  porting  guide
kicks in.

> Well, my purpose is just to find out why the 3rd instructions can not get 
> through. So I just strip everything which is temporary is not related to 
> this purpose. Do you think udelay can be a cause? I really doubt it because 
> I've tried both occasions but none of them works.

U-Boot doesn't work this way. I think it will be  very  difficult  to
get  it  working when you stumble from line to line, without tools or
understanding what's going on. There  is  a  95%  chance  that  after
solving  this  problem,  your  system will hang during or after relo-
cation to RAM.

Try to understand what the code is doing, and  if  it  actually  fits
your hardware.

BTW: are you absolutely sure your hardware is working at all?

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
Emotions are alien to me.  I'm a scientist.
	-- Spock, "This Side of Paradise", stardate 3417.3

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