ARM NIC-301 - page 22

Functional Description

ID031010 Non-Confidential

Note

When communicating with transfer-sensitive slave devices such as FIFOs, the master might not

be aware of how many read data beats have been read.

Lock transactions

The only supported lock transactions are SWP-like locks. That is, a single locking read followed

by a single unlocking write, with an undefined number of IDLE transactions in between.

Note

If the network receives a non-SWP-like lock sequence, it is possible for a network path to be

stalled, particularly if an odd number of lock transactions is issued. The stall is cancelled on the

next transaction received that unlocks the stalled path.

If you configure lock support and a GPV, then a lock override function is also configured. You

can program this option, named

lock_override

, to force no AXI lock transactions to be created.

See Chapter3 Programmers Model.

Configuration options

You can configure the following AHB options:

• AHB slave or master mirror interface types.

• Address width of 32-64 bits.

• Data width of 32. 64, 128, or 256 bits.

• Data width upsize function that Upsizing data width function on page 2-12 describes.

• Data width downsize function that Downsizing data width function on page 2-14

describes.

• Frequency domain crossing of the following types:

—ASYNC

—SYNC 1:1

—SYNC 1:n

—SYNC n:1

—SYNC n:m.

• Security of the following types:

Secure All transactions originating from this slave interface are flagged as secure

transactions and can access both secure and non-secure components.

Non-secure

All transactions originating from this slave interface are flagged as non-secure

transactions and cannot access secure components.

•

INCR promotion and Early Write Response

• Permit broken bursts using the

allow broken bursts

parameter.

• Support for the full AHB-Lite protocol with only SWAP-like locks.

Note

You can reduce the gate count and increase the performance if the attached master does

not create any AHB lock transactions.