Intel
®
81341 and 81342—Peripheral Registers
Intel
®
81341 and 81342 I/O Processors
Developer’s Manual
December 2007
1018
Order Number: 315037-002US
21.2
Accessing Peripheral Memory-Mapped Registers
The PMMR interface is a slave device connected to the 81341 and 81342 internal bus.
This interface accepts data transactions which appear on the internal bus from the ATU
and the Intel XScale
®
processors.
The PMMR interface allows these devices to perform read, write, or read-modify-write
transactions. The specific actions taken when modifying any value in the PMMR space is
independently defined within each chapter which describes the functionality of the
register.
Note:
The PMMR interface does not support multi-word burst accesses from any internal bus
master.
All PMMR transactions are allowed from the Intel XScale
®
processors operating in user
or supervisor mode. In addition, the PMMR does not provide any access exception to
the Intel XScale
®
processor.
21.3
Accessing Peripheral Registers Using the Core
Coprocessor Register Interface
Registers may be accessed/manipulated through the CCR interface with the MCR, MRC,
STC, and LDC instructions. The CRn field of the instruction denotes the register number
to be accessed. The opcode_1,and opcode_2 fields of the instruction should be zero.
The CRm field must be set to 0 for the Interrupt Controller Unit and to 1 for the
Programmable Timers. Most systems restrict access to coprocessor registers to
privileged processes. To control access to a coprocessor register, use the Coprocessor
Access Register as described in the ARM Architecture Reference Manual.
21.4
Architecturally Reserved Memory Space
The 81341 and 81342 provides 64 GBytes of address space. Portions of this address
space is architecturally reserved and users are restricted as to their function.
shows the reserved address space.
Addresses 0 0000 0000H through 0 0000 001FH are reserved for the exception vectors
of the Intel XScale
®
processor.
Addresses 0 FFFF 0000H through 0 FFFF 001FH are reserved for the relocated
exception vectors of the Intel XScale
®
processor.
29
Addresses 0 FFD8 0000H through 0 FFDF FFFFH are allocated to the PMMR interface by
default. These registers can be relocated by re-programming the PMMR Base Address
Register (PMMRBAR).
29.By enabling the Exception Vector Relocation mode (bit 13, CP15, Register 1), the Exception
Vectors (except Reset Vector at 0000 0000H) can be relocated to be based at FFFF 0000H rather
than 0000 0000H. (i.e., FIQ Vector located at FFFF 001CH)