Variation in inferring EBRs for different memory dimensions.

[veeraj_patil]

When I synthesize a 16K X 64 bit Dual port RAM, the synthesis tool infers 64 (16K)EBRs (1 bit data width for each EBR). But when I synthesize 16K X 128 bit Memory, the tool is inferring 120 EBRs(112 EBRs of 18K and 8 EBRs of 4K).

Why this variation for 16K x 128, where ideally it should infer 128 EBRs like it did for 16K x 64. ?

 

[TrickyDicky]

What is this EBR you speak of?

BRAMs and altsyncrams are usually optimised for 9 bit or 18 bit dwords.

 

[veeraj_patil]

EBR (Embedded block ram) is a BRAM. If they are optimised for 9bit then it should take anywhere in between 1 to 9 bits as data width and even then it is possible to have 128 EBRs (16k x 1).