Integrated Device Technology Inc IDT79R3052E20J, IDT79R305240MJ, IDT79R305240J, IDT79R305233MJ, IDT79R305233J Datasheet

COMMERCIAL TEMPERATURE RANGE SEPTEMBER 1995

1995 Integrated Device Technology, Inc. 5.3 DSC-3000/5

IDT79R3051/79R3052
RISControllers



IDT79R3051, 79R3051E
IDT79R3052



, 79R3052E

FEATURES:

• Instruction set compatible with IDT79R3000A and
IDT79R3001 MIPS RISC CPUs

• High level of integration minimizes system cost, power
consumption
— IDT79R3000A /IDT79R3001 RISC Integer CPU
— R3051 features 4KB of Instruction Cache
— R3052 features 8KB of Instruction Cache
— All devices feature 2kB of Data Cache
— “E” Versions (Extended Architecture) feature full

function Memory Management Unit, including 64-

entry Translation Lookaside Buffer (TLB)
— 4-deep write buffer eliminates memory write stalls
— 4-deep read buffer supports burst refill from slow

memory devices

— On-chip DMA arbiter
— Bus Interface minimizes design complexity

• Single clock input with 40%-60% duty cycle

• 35 MIPS, over 64,000 Dhrystones at 40MHz

• Low-cost 84-pin PLCC packaging that's pin-/package­compatible with thermally enhanced 84-pin MQUAD.

• Flexible bus interface allows simple, low-cost designs

• 20, 25, 33, and 40MHz operation

• Complete software support
— Optimizing compilers
— Real-time operating systems
— Monitors/debuggers
— Floating Point Software
— Page Description Languages

1

Clock

Generator

Unit

Master Pipeline Control

System Control

Coprocessor

Integer

CPU Core

Exception/Control

Registers

Memory Management

Registers

Translation

Lookaside Buffer

(64 entries)

General Registers

(32 x 32)

ALU

Shifter

Mult/Div Unit

Address Adder

PC Control

Virtual Address

Data

Cache

(2kB)

Instruction

Cache

(8kB/4kB)

Physical Address Bus

BIU

Control

DMA

Arbiter

4-deep

Read

Buffer

4-deep

Write

Buffer

Clk2xIn

Int(5:0)

32

32

BrCond(3:0)

Data Bus

Bus Interface Unit

Address/

Data

DMA

Ctrl

Rd/Wr

Ctrl

SysClk

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The IDT logo is a registered trademark, and RISChipset, RISController, R3041, R3051, R3052, R3071, R3081, R3720, R4400 and R4600 are trademarks of Integrated Device Technology, Inc.

Figure 1. R3051 Family Block Diagram

Integrated Device Technology, Inc.

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IDT79R3051/79R3052 INTEGRATED RISControllers COMMERCIAL TEMPERATURE RANGE

INTRODUCTION

The IDT IDT79R3051 family is a series of high-perfor­mance 32-bit microprocessors featuring a high level of inte­gration which are targeted to high-performance, but cost­sensitive embedded processing applications. The IDT79R3051
family is designed to bring the high-performance inherent in
the MIPS RISC architecture into low-cost, simplified, power­sensitive applications.

Functional units were integrated onto the CPU core in order
to reduce the total system cost, without significantly degrading
system performance. Thus, the IDT79R3051 family is able to
offer 35MIPS of integer performance at 40MHz without requir­ing external SRAM or caches.

Furthermore, the IDT79R3051 family brings dramatic power
reduction to these embedded applications, allowing the use of
low-cost packaging for devices up to 25 MHz. The IDT79R3051
family allows customer applications to bring maximum per­formance at minimum cost.

Figure 1 shows a block-level representation of the func­tional units within the IDT79R3051 family. The IDT79R3051
family could be viewed as the embodiment of a discrete
solution built around the IDT79R3000A or IDT79R3001.
However, by integrating this functionality on a single chip,
dramatic cost and power reductions are achieved.

Currently, there are four members of the IDT79R3051
family. All devices are pin- and software-compatible: the
differences lie in the amount of instruction cache, and in the
memory management capabilities of the processor:

• The IDT79R3052"E” incorporates 8kB of Instruction Cache,

and features a full-function Memory Management Unit
(MMU), including a 64-entry fully-associative Translation
Lookaside Buffer (TLB). This is the same MMU incorporated
into the IDT79R3000A and IDT79R3001.

• The IDT79R3052 also incorporates 8kB of Instruction Cache.

However, the MMU is a much simpler subset of the capabili­ties of the enhanced versions of the architecture, and in fact
does not use a TLB.

• The IDT79R3051"E” incorporates 4KB of Instruction Cache.

Additionally, this device features the same full-function
MMU (including TLB file) as the IDT79R3052"E”, and
IDT79R3000A.

• The IDT79R3051 incorporates 4KB of Instruction Cache,

and uses the simpler memory management model of the
IDT79R3052.

An overview of the functional blocks incorporated in these
devices follows.

CPU Core

The CPU core is a full 32-bit RISC integer execution
engine, capable of sustaining close-to single cycle execution
rate. The CPU core contains a five stage pipeline and 32
orthogonal 32-bit registers. The IDT79R3051 family imple­ments the MIPS ISA. In fact, the execution engine of the
IDT79R3051 family is the same as the execution engine of the
IDT79R3000A (and IDT79R3001). Thus the IDT79R3051
family is binary-compatible with those CPU engines.

Figure 2. R3051 Family 5-Stage Pipeline

The execution engine of the IDT79R3051 family uses a
five-stage pipeline to achieve close-to single cycle execution.
A new instruction can be started in every clock cycle; the
execution engine actually processes five instructions con­currently (in various pipeline stages). Figure 2 shows the
concurrency achieved by the IDT79R3051 family pipeline.

IF

Current

CPU

Cycle

I#1 ALURD MEM WB

IFI#2 ALURD MEM WB

IFI#3 ALURD MEM WB

IFI#4 ALURD MEM WB

IFI#5 ALURD MEM WB

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System Control Co-Processor

The R3051 family also integrates on-chip the System
Control Co-processor, CP0. CP0 manages both the excep­tion handling capability of the IDT79R3051 family, as well as
the virtual to physical mapping of the IDT79R3051 family.

There are two versions of the IDT79R3051 family architec­ture: the Extended Architecture Versions (the IDT79R3051E
and IDT79R3052E) contain a fully associative 64-entry TLB
which maps 4KB virtual pages into the physical address
space. The virtual to physical mapping thus includes kernel
segments which are hard mapped to physical addresses, and
kernel and user segments which are mapped on a page basis
by the TLB into anywhere within the 4GB physical address
space. In this TLB, 8-page translations can be “locked” by the
kernel to insure deterministic response in real-time applica­tions. These versions thus use the same MMU structure as
that found in the IDT79R3000A and IDT79R3001. Figure 3
shows the virtual-to-physical address mapping found in the
Extended Architecture versions of the processor family.

The Extended Architecture devices allow the system
designer to implement kernel software to dynamically manage
User task utilization of memory resources, and also allow the
Kernel to effectively “protect” certain resources from user
tasks. These capabilities are important in a number of
embedded applications, from process control (where resource
protection may be extremely important) to X-Window display
systems (where virtual memory management is extremely
important), and can also be used to simplify system debugging.

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IDT79R3051/79R3052 INTEGRATED RISControllers COMMERCIAL TEMPERATURE RANGE

Figure 3. Virtual-to-Physical Mapping of Extended Architecture Versions

Kernel Mapped

(kseg2)

Kernel Uncached

(kseg1)

Kernel Cached

(kseg0)

User Mapped

Cacheable

(kuseg)

Physical

Memory

Memory

0xffffffff

0xc0000000

0xa0000000

0x80000000

0x00000000

3548MB

512MB

Any

Any

VIRTUAL PHYSICAL

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Figure 4. Virtual-to-Physical Mapping of Base Architecture Versions

1MB Kernel Rsvd

Kernel Cacheable

Tasks

Kernel/User

Cacheable

Tasks

Inaccessible

Kernel Boot

and I/O

0xffffffff

0xc0000000

0xa0000000

0x80000000

0x00000000

1024MB

2048MB

512MB

512MB

VIRTUAL PHYSICAL

Kernel Cached

(kseg2)

Kernel Uncached

(kseg1)

Kernel Cached

(kseg0)

User
Cached
(kuseg)

1MB User Rsvd

2874 drw 04

The base versions of the architecture (the IDT79R3051
and IDT79R3052) remove the TLB and institute a fixed
address mapping for the various segments of the virtual
address space. The base processors support distinct kernel
and user mode operation without requiring page management
software, leading to a simpler software model. The memory
mapping used by these devices is illustrated in Figure 4. Note
that the reserved address spaces shown are for compatibility
with future family members; in the current family members,
references to these addresses are translated in the same
fashion as their respective segments, with no traps or excep­tions taken.

When using the base versions of the architecture, the
system designer can implement a distinction between the
user tasks and the kernel tasks, without having to execute
page management software. This distinction can take the
form of physical memory protection, accomplished by ad­dress decoding, or in other forms. In systems which do not
wish to implement memory protection, and wish to have the
kernel and user tasks operate out of a single unified memory
space, upper address lines can be ignored by the address
decoder, and thus all references will be seen in the lower
gigabyte of the physical address space.

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IDT79R3051/79R3052 INTEGRATED RISControllers COMMERCIAL TEMPERATURE RANGE

Clock Generation Unit

The IDT79R3051 family is driven from a single input clock,
capable of operating in a range of 40%-60% duty cycle. On
chip, the clock generator unit is responsible for managing the
interaction of the CPU core, caches, and bus interface. The
clock generator unit replaces the external delay line required
in IDT79R3000A and IDT79R3001 based applications.

Instruction Cache

The current family includes two different instruction cache
sizes: the IDT79R3051 family (the IDT79R3051 and
IDT79R3051E) feature 4KB of instruction cache, and the
IDT79R3052 and IDT79R3052E each incorporate 8KB of
Instruction Cache. For all four devices, the instruction cache
is organized as a line size of 16 bytes (four words). This
relatively large cache achieves a hit rate well in excess of 95%
in most applications, and substantially contributes to the
performance inherent in the IDT79R3051 family. The cache is
implemented as a direct mapped cache, and is capable of
caching instructions from anywhere within the 4GB physical
address space. The cache is implemented using physical
addresses (rather than virtual addresses), and thus does not
require flushing on context switch.

Data Cache

All four devices incorporate an on-chip data cache of 2KB,
organized as a line size of 4 bytes (one word). This relatively
large data cache achieves hit rates well in excess of 90% in
most applications, and contributes substantially to the perfor­mance inherent in the IDT79R3051 family. As with the instruc­tion cache, the data cache is implemented as a direct mapped
physical address cache. The cache is capable of mapping any
word within the 4GB physical address space.

The data cache is implemented as a write through cache,
to insure that main memory is always consistent with the
internal cache. In order to minimize processor stalls due to
data write operations, the bus interface unit incorporates a 4­deep write buffer which captures address and data at the
processor execution rate, allowing it to be retired to main
memory at a much slower rate without impacting system
performance.

Bus Interface Unit

The IDT79R3051 family uses its large internal caches to
provide the majority of the bandwidth requirements of the
execution engine, and thus can utilize a simple bus interface
connected to slow memory devices.

The IDT79R3051 family bus interface utilizes a 32-bit
address and data bus multiplexed onto a single set of pins.
The bus interface unit also provides an ALE signal to de­multiplex the A/D bus, and simple handshake signals to
process processor read and write requests. In addition to the
read and write interface, the IDT79R3051 family incorporates
a DMA arbiter, to allow an external master to control the
external bus.

The IDT79R3051 family incorporates a 4-deep write buffer
to decouple the speed of the execution engine from the speed

of the memory system. The write buffers capture and FIFO
processor address and data information in store operations,
and presents it to the bus interface as write transactions at the
rate the memory system can accommodate.

The IDT79R3051/52 read interface performs both single
word reads and quad word reads. Single word reads work with
a simple handshake, and quad word reads can either utilize
the simple handshake (in lower performance, simple sys­tems) or utilize a tighter timing mode when the memory system
can burst data at the processor clock rate. Thus, the system
designer can choose to utilize page or nibble mode DRAMs
(and possibly use interleaving), if desired, in high-perfor­mance systems, or use simpler techniques to reduce com­plexity.

In order to accommodate slower quad-word reads, the
IDT79R3051 family incorporates a 4-deep read buffer FIFO,
so that the external interface can queue up data within the
processor before releasing it to perform a burst fill of the
internal caches. Depending on the cost vs. performance
tradeoffs appropriate to a given application, the system design
engineer could include true burst support from the DRAM to
provide for high-performance cache miss processing, or uti­lize the read buffer to process quad word reads from slower
memory systems.

SYSTEM USAGE

The IDT79R3051 family has been specifically designed to
easily connect to low-cost memory systems. Typical low-cost
memory systems utilize slow EPROMs, DRAMs, and applica­tion-specific peripherals. These systems may also typically
contain large, slow Static RAMs, although the IDT79R3051
family has been designed to not specifically require the use of
external SRAMs.

Figure 5 shows a typical system block diagram. Transpar­ent latches are used to de-multiplex the IDT79R3051/52
address and data busses from the A/D bus. The data paths
between the memory system elements and the R3051 family
A/D bus is managed by simple octal devices. A small set of
simple PALs can be used to control the various data path
elements, and to control the handshake between the memory
devices and the CPU.

DEVELOPMENT SUPPORT

The IDT79R3051 family is supported by a rich set of
development tools, ranging from system simulation tools
through prom monitor support, logic analysis tools, and sub­system modules.

Figure 7 is an overview of the system development process
typically used when developing IDT79R3051 family-based
applications. The IDT79R3051 family is supported by power­ful tools through all phases of project development. These
tools allow timely, parallel development of hardware and
software for IDT79R3051/52 based applications, and include
tools such as:

• A program, Cache-3051, which allows the performance of

an IDT79R3051 family based system to be modeled and
understood without requiring actual hardware.

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IDT79R3051/79R3052 INTEGRATED RISControllers COMMERCIAL TEMPERATURE RANGE

• Sable, an instruction set simulator.

• Optimizing compilers from MIPS, the acknowledged leader
in optimizing compiler technology.

• IDT Cross development tools, available in a variety of
development environments.

• The high-performance IDT floating point library software,
which has been integrated into the compiler toolchain to
allow software floating point to replace hardware floating
point without modifying the original source code.

• The IDT Evaluation Board, which includes RAM, EPROM,
I/O, and the IDT Prom Monitor.

• The IDT Laser Printer System board, which directly drives
a low-cost print engine, and runs Microsoft TrueImage



Page Description Language on top of PeerlessPage Ad­vanced Printer Controller BIOS.

• Adobe PostScript



Page Description Language, ported to

the R3000 instruction set, runs on the IDT79R3051 family.

• The IDT Prom Monitor, which implements a full prom
monitor (diagnostics, remote debug support, peek/poke,
etc.).

• An In-Circuit Emulator, developed and sold by Embedded
Performance, Inc.

Figure 5. Typical R3051 Family Based System

Reset

Clk2xIn

Int(5:0)

BrCond(3:0)

BusReq

BusGnt

AD(31:0) ALE Addr(3:2)

SysClk Rd

Wr

Ack

RdCEn

DataEn

Burst/

WrNear

BErr

Memory and Interface

Control PALs

Address

Decode

PAL

FCT373T

DRAM Control

PALs

DRAM

FCT245T

EPROM

I/O Devices/

Peripherals

System I/O

IDT R3051 Family

RISController

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5.3 6

IDT79R3051/79R3052 INTEGRATED RISControllers COMMERCIAL TEMPERATURE RANGE

Figure 6. R3051 Family Chip Set Based System

Clk2xIn

IDT79R3051 Family

RISController

Address/

Data

Control

I/O Controller

DRAM

Controller

DRAM DRAMPROM I/O I/O

IDT73720

Bus Exchanger

R3051 Family

Local Bus

(2)

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5.3 7

IDT79R3051/79R3052 INTEGRATED RISControllers COMMERCIAL TEMPERATURE RANGE

Figure 7. R3051 Family Development Toolchain

Cache-R305x

Benchmarks

Evaluation Board

Laser Printer System

SABLE Simulator

DBG Debugger

PIXIE Profiler

MIPS Compiler Suite

Stand-Alone Libraries

Floating Point Library

Cross Development Tools

Adobe PostScript

 PDL

MicroSoft TrueImage

 PDL

Ada

Cache-R305x

Hardware Models
General CAD Tools
RISC Sub-systems

Evaluation Board

Laser Printer System

Hardware

Software

Logic Analysis

Diagnostics

IDT PROM Monitor

Remote Debug

Real-Time OS

In-Circuit Emulator

System

Architecture

Evaluation

System

Development

Phase

System

Integration

and Verification

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