[U-Boot-Users] Software emulation exception on entry into RAM

[Thomas Laman]

Wolfgang Denk wrote:

>In message <410A157E.5060307 at rochester.rr.com> you wrote:
>  
>
>>In my board specific code, after initialization of the SDRAM, I have 
>>    
>>
>code that writes the address as data to that address - write 0x0 to 0x0, 
>  
>
>>0x4 to 0x4, etc. After the Software Emulation Exception, I go into the 
>>SDRAM and the code is copied correctly in the used areas, and my pattern 
>>is in the other areas.
>>    
>>
>
>And which data are you RADING from SDRAM? 
>  
>
The data that was copied prior to the branch to SDRAM.

>  
>
>>Because of this, I don't think my SDRAM settings are being changed.
>>    
>>
>
>You wrote you are using a BDI2000 - you can use  it  to  single  step
>into  the  code  in  SDRAM.  What  does  this give? And if you get an
>exception - where does it happen? What was the incorrect data?
>
>  
>
I get an exception on the first access of SDRAM (the address branched to 
from flash). The data is correct. I will have access to a logic analyzer 
this weekend and will check out the SDRAM burst read access.

>You got the tools - use it to analyze your problem [or just save  the
>time   and  re-check  your  SDRAM  initialization  against  the  chip
>manufacturer's manual; at least this is what I would do if I  was  in
>your position.]
>
>  
>
I have checked the SDRAM initialization and it appears to be correct. 
With the logic analyzer, I will check out the burst read cycle.

>Best regards,
>
>Wolfgang Denk
>
>  
>