ARM Technical Support Knowledge Articles

Can an AHB WRAP burst cross a 1KB boundary?

Applies to: Micropack v2.0

Answer

No, it is a protocol violation for any AHB burst to cross a 1KB boundary.

There is only one possible (illegal) way that this could ever happen, which is when HBURST = WRAP16 and HSIZE = 1024-bit.  This burst would have a total transfer size of 2KB, meaning at some point a 1KB boundary would have to be crossed.

It is impossible for any other wrapping transfer (either less than WRAP16 OR less than HSIZE = 1024-bit) to cross a 1KB boundary, because the total transfer size is at most 1KB.  Therefore, it would be required to wrap at the 1KB boundary when approaching a 1KB boundary (and wouldn't cross it).

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