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DDR and DDR2 SDRAM High-Performance Controller User Guide: question

Altera_Forum
Honored Contributor II
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Could somebody please explain the following from page 4-16 of 

the DDR and DDR2 SDRAM High-Performance Controller User Guide: 

 

To map local_wdata and local_be to mem_dq and mem_dm, consider the 

following full rate example with 32-bit wide local_wdata and 16-bit wide 

mem_dq. 

 

local_wdata = <22334455> <667788AA> <BBCCDDEE> 

local_be = <1100> <0110> <1010> 

These map to: 

mem_dq = <4455> <2233> <88AA> <6677> <DDEE> <BBCC> 

mem_dm = <1 1> <0 0> <0 1> <1 0> <0 1> <0 1> 

 

how did they arrive at local_be and mem_dm? 

Thanks MikeZ
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