3.3.11 Shareable Override Register

This register overrides the shareability characteristics of Normal transactions that are received on the relevant interface. Overriding of the shareability settings does not occur for FIXED bursts, Device transactions, or DVM message transactions.

Usage constraints
This register is for ACE-Lite slave interfaces only.
Accessible using only Secure accesses, unless you set the Secure Access Register to permit Non-secure accesses.
Available in all CCI-550 configurations.
An instance of this register exists for each slave interface.
See 3.2 Register summary for more information.


Exclusive accesses must not be issued on an interface that is being overridden as shareable. If the CCI-550 is programmed to override transactions as shareable, exclusive accesses are overridden to normal accesses. An exclusive write then receives an OKAY response to indicate that the slave does not support exclusive accesses.
The following figure shows the bit assignments.
Figure 3-9 share_ovr register bit assignments
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The following table shows the bit assignments.

Table 3-12 share_ovr register bit assignments

Shareable override for slave interface:
0b00-0b01Do not override AxDOMAIN inputs.
Override AxDOMAIN inputs to 0b00, meaning that all transactions are treated as Non-shareable:
  • ReadOnce becomes ReadNoSnoop.
  • WriteUnique and WriteLineUnique become WriteNoSnoop.
  • CleanShared, CleanInvalid, and MakeInvalid transactions do not generate snoops.
Override AxDOMAIN inputs to 0b01, meaning that all Normal transactions are treated as Shareable:
  • ReadNoSnoop becomes ReadOnce.
  • WriteNoSnoop becomes WriteUnique.
  • CleanShared, CleanInvalid, and MakeInvalid transactions generate snoops.
Related reference
3.3.2 Secure Access Register
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