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

Wolfgang Denk wd at denx.de
Fri Jul 30 11:56:58 CEST 2004

In message <41099EFD.7060702 at rochester.rr.com> you wrote:
> I am implementing u-boot 1.0.2 on a custom 860P board and am getting a 
> Software Emulation Exception
> (as reported by BDI2000) at the first access of RAM after code is copied 

...whbich is most probably caused by incorrect initialization of the SDRAM.

> The SDRAM setup was copied from a working PSOS+ load running on this 
> board. Successful burst
> reads have been verified with a logic analyzer. I can't easily get 
> access to the logic analyzer for debugging
> u-boot.

Did you verify with the LA which data  was  actually  read  from  RAM
after relocation?

> I have defined SRAM to be at 0x0 and I get the same results.

I don't understand what you mean here. 

> I have searched the list and have found cases where SDRAM 
> initialization/burst read configurations have been
> blamed. Based on success w/ PSOS+, I don't think this is my problem.

I still think it is. I have seen  PSOS  systems  running  happily  on
systems  where  a  real  OS  would  reliably  crash because of memory

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
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