9.2.5. AXI extensions

The Cortex-R5 AXI master interface uses the ARCACHEMm, AWCACHEMm, AXI signals and the ARSHAREMm, AWSHAREMm, ARINNERMm, and AWINNERMm extension signals to indicate the memory attributes of the transfer, as returned by the MPU. Table 9.2 shows the encodings used for these signals. ARCACHEMm and AWCACHEMm of the master interface are generated from the memory type and outer region attributes. ARINNERMm and AWINNERMm are generated from the memory type and inner region attributes. ARSHAREMm and AWSHAREMm are asserted for transactions to shared memory regions.

Table 9.2. ARCACHEMm, AWCACHEMm, ARINNERMm, and AWINNERMm encodings

Encoding[a]Meaning
b0000Strongly Ordered
b0001Device
b0011Non-cacheable
b0110Cacheable, write-through, allocate on reads only
b0111Cacheable, write-back, allocate on reads only
b1111Cacheable write-back, allocate on reads and writes

[a] All encodings not shown in the table are reserved.


Additional AXI extension signals on all the AXI master channels are used for bus-ECC and parity information.

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