14.7. External private peripheral interface

The external private peripheral interface is an APB (AMBA v2.0) bus. Data and debug accesses to the External Peripheral memory space (0xE0040000 - 0xE00FFFFF) are performed over this bus. Wait states are not supported on this bus. The TPIU and any vendor specific components populate this bus. Core data accesses have higher priority than debug accesses, so debug accesses are waited until core accesses have completed when there are simultaneous core and debug access to this bus. Only the address bits necessary to decode the External PPB space are supported on this interface. These address bits are bits [19:2] of PADDR.

PADDR31 is driven as a sideband signal on this bus. When the signal is HIGH, it indicates that the AHB-AP debug is the requesting master. When the signal is LOW, it indicates that the core is the requesting master.

Unaligned accesses to this bus are architecturally Unpredictable and are not supported. The processor drives out the original HADDR[1:0] request from the core and does not convert the request into multiple aligned accesses.

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