NXP Semiconductors freescale KV4 Series, Reference Manual

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21.5 Introduction
The peripheral bridge converts the crossbar switch interface to an interface that can
access most of the slave peripherals on this chip.
The peripheral bridge occupies 64 MB of the address space, which is divided into
peripheral slots of 4 KB. (It might be possible that all the peripheral slots are not used.
See the memory map chapter for details on slot assignments.) The bridge includes
separate clock enable inputs for each of the slots to accommodate slower peripherals.
21.5.1 Features
Key features of the peripheral bridge are:
• Supports peripheral slots with 8-, 16-, and 32-bit datapath width
• Programming model provides memory protection functionality
21.5.2 General operation
The slave devices connected to the peripheral bridge are modules which contain a
programming model of control and status registers. The system masters read and write
these registers through the peripheral bridge. The peripheral bridge performs a bus
protocol conversion of the master transactions and generates the following as inputs to
the peripherals:
• Module enables
• Module addresses
• Transfer attributes
• Byte enables
• Write data
The peripheral bridge selects and captures read data from the peripheral interface and
returns it to the crossbar switch.
The register maps of the peripherals are located on 4-KB boundaries. Each peripheral is
allocated one or more 4-KB block(s) of the memory map.
The AIPS-Lite module uses the data width of accessed peripheral to perform proper data
byte lane routing; bus decomposition (bus sizing) is performed when the access size is
larger than the peripheral's data width.
Introduction
KV4x Reference Manual, Rev. 2, 02/2015
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Preliminary
Freescale Semiconductor, Inc.