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ACE Transaction Types

The specialized read and write transactions added to AXI for coherency.

ACE adds over 20 new transaction types. Here are the most critical ones for verification.

Non-Caching Transactions

Standard ReadNoSnoop and WriteNoSnoop are used when the Master doesn't want to affect its cache states (IO Coherent only).

Coherent Read Transactions

  • ReadShared: Master wants a copy of the line to read. Doesn't mind if others have it.
  • ReadUnique: Master wants a copy so it can write to it. Interconnect must invalidate other copies.

Verification Tip

Observe the ARDOMAIN and ARSNOOP signals. They tell the interconnect if the transaction needs snooping and what type of coherency operation to perform.
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