ARM R4 Computer Hardware User Manual


 
Introduction
ARM DDI 0363E Copyright © 2009 ARM Limited. All rights reserved. 1-4
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1.3 Components of the processor
This section describes the main components of the processor:
Data Processing Unit on page 1-5
Load/store unit on page 1-5
Prefetch unit on page 1-5
L1 memory system on page 1-5
L2 AXI interfaces on page 1-7
Debug on page 1-8
System control coprocessor on page 1-9
Interrupt handling on page 1-9.
Figure 1-1 shows the structure of the processor.
Figure 1-1 Processor block diagram
The PreFetch Unit (PFU) fetches instructions from the memory system, predicts branches, and
passes instructions to the Data Processing Unit (DPU). The DPU executes all instructions and
uses the Load/Store Unit (LSU) for data memory transfers. The PFU and LSU interface to the
L1 memory system that contains L1 instruction and data caches and an interface to a L2 system.
The L1 memory can also contain optional TCM interfaces.
Processor
Level two interface
Level one memory system
AXI master bus
AXI slave bus
L2 interface
AXI
master port
Data
Processing
Unit
Memory
Protection
Unit
Prefetch Unit
Load/Store
Unit
L2 interface
AXI
slave port
Tightly-
Coupled
Memory
(TCM)
interface
B0TCM
B1TCM
ATCM
L1
instruction
cache control
L1
instruction
cache RAM
L1
data cache
control
L1
data
cache RAM
Debug
Debug
interface
ETM
ETM
interface