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21369 SDRAM problem, two 16-bit devices arranged as a single 32-bit

Question asked by AstroMedGlen on Sep 16, 2009
Latest reply on Sep 23, 2009 by AstroMedGlen

Hello,

 

      I am experiencing an odd problem with my SDRAM. I have a single 21369 processor attached to two Micron MT48LC16M16 16-bits SDRAM chips. The chips are arranged to function as a single 32-bit device. They are attached via MS1. It appears as though I have some functionality of the memory, but its behavior is a bit bizarre. Every four addresses seem fine, the next four do not, then repeat. For example if I do a mem fill from VDSP of twenty addresses starting at XXXX00 with data 1234ABCD I would get something like:

 

XXXX00 : 1234ABCD

XXXX01 : 1234ABCD

XXXX02 : 1234ABCD

XXXX03 : 1234ABCD

XXXX04 : 00000000

XXXX05 : 00000000

XXXX06 : 00000000

XXXX07 : 00000000

XXXX08 : 1234ABCD

XXXX09 : 1234ABCD

XXXX0A : 1234ABCD

XXXX0B : 1234ABCD

XXXX0C : 00000000

XXXX0D : 00000000

XXXX0E : 00000000

XXXX0F : 00000000

XXXX10 : 1234ABCD

XXXX11 : 1234ABCD

XXXX12 : 1234ABCD

XXXX13 : 1234ABCD

 

   I can provide details on pin connections and setup code if need be. Just thought I'd throw this out there first.

 

Glen

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