Freescale Semiconductor MPC5553 - Introduction

MPC5553/MPC5554 Microcontroller Reference Manual, Rev. 5
Freescale Semiconductor 5-1
Chapter 5
Peripheral Bridge (PBRIDGE_A, PBRIDGE_B)
5.1 Introduction
5.1.1 Block Diagram
The PBRIDGE is the interface between the system bus and on-chip peripherals as shown in Figure 5-1.
Figure 5-1. PBRIDGE Interface
5.1.2 Overview
There are two peripheral bridges, PBRIDGE_A and PBRIDGE_B, which act as interfaces between the
system bus and lower bandwidth peripherals. In this manual, PBRIDGE refers to either of these bridges,
as their functionality is identical. The only difference is the peripherals to which they connect. Accesses
that fall within the address space of the PBRIDGE are decoded to provide individual module selects for
peripheral devices on the slave bus interface.
5.1.2.1 Access Protections
The PBRIDGE provides programmable access protections for both masters and peripherals. It allows the
privilege level of a master to be overridden, forcing it to user mode privilege, and allows masters to be
designated as trusted or untrusted. Peripherals may require supervisor privilege level for access, may
restrict access to a trusted master only, and may be write-protected. See Table 5-1 for a list of master/slave
IDs and the peripherals associated with each master and slave. More information on access protection may
be found in Section 13.3.2.9, “Flash Bus Interface Unit Access Protection Register (FLASH_BIUAPR).”
Off-platform Slave
Peripheral
On-platform Slave
Peripheral
Bridge A
(PBRIDGE_B)(PBRIDGE_A)
Bridge B
Off-platform Slave
System Bus
System Bus
System Bus Crossbar Switch (XBAR)
On-platform Slave