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mpc8540 and SDRAM burst

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mpc8540 and SDRAM burst

Postby Armand Ciejak » Tue Jan 24, 2006 11:13 am

I'm using the mpc8540 processor with QNX 6.3.0 SP2.
It has the main memory in DDR-RAM. In addition there is a small SD-RAM
on the local bus. Accesses to this memory (SD-RAM) is really slow, since
the processor never uses burst accesses. The documentation claims that
the processor always performs burst accesses but it doesn't (I attached
a scope to the local bus)!
Is there any special functions to use in order to force burst access?
I already tried different settings for the SD-RAM controller: cache
disabled, enabled, witre-through, write back, ...

Do I have to solve this issue in QNX or at a lower level (asm instructions)?

Thanks
Armand Ciejak
 

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