Why the "Maximum Avalon-MM burst length" options in DDR2/DDR3 SDRAM UniPHY based Controller does not match with the other Platform Designer component like "Maximum burst size (words)" in Avalon®-Memory Mapped Pipeline Bridge?

Description

You may see the DDR2/DDR3 SDRAM UniPHY based Controller has “Maximum Avalon®-MM burst length” options {1, 3, 7, 15, 31, 63, 127, 255, 511, 1023, 2047}.

 

While Avalon-MM Pipeline Bridge has “Maximum burst size (words)” options {1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024} in Quartus® II software version 11.1SP2.

 

The “Maximum Avalon-MM burst length” value choices in DDR2/DDR3 SDRAM UniPHY based Controller is incorrect.

Resolution

The actual maximum burst length implied by the “Maximum Avalon-MM burst length” options in DDR2/DDR3 SDRAM UniPHY based Controller is shown below:

 

1 -> 1

3 -> 2

7 -> 4

15 -> 8

31 -> 16

63 -> 32

127 -> 64

255 -> 128

511 -> 256

1,023 -> 512

2,047 -> 1,024