boundary concept

Hi all,

I am new to protocols AHB and AXI.

can anyone explain why there is 4kb boundary in AXI and why there is 1 kb boundary in AHB?

Also what these boundaries are for? Does they represent the maximum slave size?

Parents
  • As to why AHB is 1kB and AXI is 4kB, this is simply down to the age of the protocols. When AHB was first released in 1999 it wasn't common to see wide data buses (32-bits and 64-bits would be common), so with a maximum defined burst length of 16 this meant typically 128-byte long bursts, which wouldn't often be impacted by the 1024 byte boundaries. However AXI first released in 2003 started to see wider data buses implemented, 

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  • As to why AHB is 1kB and AXI is 4kB, this is simply down to the age of the protocols. When AHB was first released in 1999 it wasn't common to see wide data buses (32-bits and 64-bits would be common), so with a maximum defined burst length of 16 this meant typically 128-byte long bursts, which wouldn't often be impacted by the 1024 byte boundaries. However AXI first released in 2003 started to see wider data buses implemented, 

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