IDT75P42100S100BSI - Integrated Device Technology, Inc.

OCTOBER 2001

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2002 Integrated Device Technology, Inc.

Features

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◆Full Ternary 32K x 72 bit content addressable memory

◆◆

◆Upgradeable to 64K x 72 and 128K x 72 IPCs

◆◆

◆Power Management

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◆Global Mask Registers

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◆Segments individually configurable

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◆36/72/144/288/576 multiple width lookups

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◆100M sustained lookups per second at 72 and 144 width lookups

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◆Burst write for high speed table updates

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◆Multi-match

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◆Learn new entries

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◆Dual bus interface

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◆Cascadable to 8 devices with no glue logic or latency penalty

◆◆

◆Glueless interface to standard ZBT™ or

Synchronous Pipelined Burst SRAMs

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◆Boundary Scan JTAG Interface (IEEE 1149.1compliant)

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◆1.8V core power supply

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◆2.5V VBIAS power supply

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◆User selectable 2.5V or 1.8V I/O supply

IP Co-Processor

32K x 72 Entries Datasheet

Brief

75P42100

Device Description

IDT’s 75P42100 IPC is a high performance pipelined low-power,

synchronous full-ternary 32K x 72 entry device. Each entry location in

the IPC has both a Data entry and an associated Mask entry. IDT’s IPC

devices integrate content addressable memory (CAM) technology with

high-performance logic. The device can perform Lookup and Learn IPC

operations plus Read, Write, Burst Write, and Dual Write maintenance

operations.

The IDT 75P42100 IPC device has a bi-directional bus that is a

multiplexed address and data bus that can support 100 million sustained

searches per second. This device provides array segments which can

be configured to enable multiple width lookups from 36 to 576 bits wide.

The IDT 75P42100 requires a 1.8-volt VDD supply, a user selectable 1.8

or 2.5-volt VDDQ supply, and a 2.5-volt VBIAS supply. This IPC device

provides the user with flexibility and control in determining the device

power. Only the array segments that will be used for a specific IPC

operation are powered up while the unused segments are not.

The IDT 75P42100 utilizes IDT’s latest high-performance 1.8V

CMOS processing technology and is packaged in a JEDEC Standard,

thermally enhanced, low profile Ball Grid Array. The options include a

304 BGA, satisfying smaller footprint requirements and a 372 BGA

package that is compatible with IDT's 64K x 72 Entry (75P52100) and

128K x 72 Entry (75K62100) IPC devices.

Configuration Registers

and

Ram Control Circuits

CLOCK

CCLK

÷2

PHASE

SRAM CONTROL

Address

MMOUT

MATCHOUT

REQSTB R/W

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RESET

Command

Bus

Request

Data

Bus

Index

Bus

Counter

BURST

IPC

REQUEST

BUS

IPC

RESPONS

BUS

LAST IPC

LAST SRAM

ASIC FEEDBACK

Bypass

DATA

ARRAY

Comparand Registers

Instruction

Global Mask Registers

Result Register

Block Diagram

Figure 1.0 ASIC / Compatible IPC / SRAM configuration

System Configurations

IDT’s IPCs are designed to fulfill the needs of various types of

networking systems. In solutions requiring data searching such as

routers, a system configuration as shown in Figure 1.0 may be realized.

Maximum flexibility is provided by allowing one board design to be

populated today using either IDT’s 75P42100 or 75P52100 IPCs and

later upgraded to use IDT’s 75K62100 IPC. Applications note AN-279

discusses how to accommodate one board design for any of these IPCs.

In this compatible configuration, the IPC interfaces directly to an

ASIC/ FPGA for lookups and routes an Index to an associated SRAM

device, which supplies the next hop address via an SRAM Data Bus to

the ASIC. The IPC provides the required control signals to directly

hookup to ZBT™ or Synchronous Pipeline Burst SRAM. Lookup results

can also be fed directly back to the ASIC/ FPGA without the use of external

SRAM. Control of the associated handshake signals is provided by all

IPCs to adapt to either configuration.

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Optional

Network Interface

ASIC

FPGA

ZBT

Sync SRAM

To request the full IDT75P42100 datasheet, please contact your local

IDT Sales Representative or call 1-831-754-4555

IDT

75P42100

75P52100

75K62100

IP Co-Processor

IP Co-Processor 32K x 72 Entries Datasheet Brief 75P42100

SRAM Interface

The IPC provides all required address and control signals for a

glueless SRAM interface. The IPC provides a pipelined bypass path for

reads or writes to the external SRAM. The ASIC/FPGA handles the

pipelining of the data to and from the SRAM.

Registers

There are four basic types of registers supported:

◆ Configuration Registers are used at initialization to define the

segmentation of the entries, timing of outputs and the SRAM interface.

◆ Global Mask Registers are provided to support Lookup

instructions by masking individual bits during a search.

◆ Comparand Registers assist in the Learn Instruction.

◆ Result Registers are used to store the resulting index of a

search from a Lookup or Learn operation.

Synchronous Burst Write

The burst write feature has no limit on the number of continuous write

accesses and supports initialization of the IPC.

Width Segmentation Capability

The IPCs are capable of performing lookups for comparisons on data

structures of 72 bits, 144 bits, 288 bits and 576 bits. These devices has

can be configured to meet various system requirements.

◆Single Width Array

◆Multiple Width Arrays within a Single Device

Multi Match

The Multi-Match feature signals to the user that more than one match

has resulted. The result of the lookup, which defines the highest priority

match, is sent along with the Multi-Match signal.

Power Savings and Classification Features

See the full IDT75P42100 Datasheet for more information.

Functional Highlights

Figure 1.1

Bus Interface

The IPC utilizes a dual bus interface consisting of the IPC Request Bus

and the IPC Response Bus.

The IPC Request Bus is comprised of the Command Bus and the

Request Data Bus. The Command Bus handles the instruction to the IPC

while the Request Data Bus is the main data path to the IPC.

The 72 bit bi-directional Request Data Bus functions as a multiplexed

address and data bus, which performs the writing and reading of IPC

entries, as well as presenting lookup data to the device.

The IPC Response Bus is comprised of an independent unidirectional

Index Bus which drives the result of the lookup (or index) to either an

SRAM device or an ASIC. In addition to driving the Index, the IPC

Response Bus also drives the associated SRAM control signals (CE/OE,

and WE) for either ZBT™ or Synchronous Pipeline Burst SRAM devices.

Command Bus

The Command Bus loads the specific instructions into the IPC. These

include:

◆ Read or Write

A Read or Write instruction operates on a specified data entry, mask

entry, or register.

◆ SRAM No Wait Read

An SRAM No Wait Read is a Read instruction to an external SRAM

that can be pipelined within a series of operations and does not require

the user to wait for the Read to complete before loading the next instruction.

◆ Dual Write

In addition to individual writes, the IPC has the ability to perform

simultaneous writes to a Data entry and a respective external SRAM

location.

Data and Mask Array

The IPC has Data cell entries and associated

Mask cell entries as shown in Fig. 1.1. This

combination of Data and Mask cell entries en-

ables the IPC to store 0, 1 or X, making it a full

ternary IP Co-Processor. During a lookup

operation, both arrays are used along with a

Global Mask Register to find a match to a re-

quested data word.

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Data

Mask

◆ Lookup

A lookup can be requested in 72-bit, 144-bit, 288-bit or 576-bit widths.

A 36-bit lookup can be accomplished by using two Global Mask Registers.

◆ Learn

The IPC implements a fully autonomous Learn Instruction, which

provides a mechanism for the user to write a lookup entry into an unused

location in the IPC and the associated data in external SRAM. This allows

the user to update an entry into the IPC which had not previously been stored.

The Learn writes the new entry, making it available for future lookups.

6.42

IP Co-Processor 32K x 72 Entries Datasheet Brief 75P42100

Signal Descriptions

Pin Function I/O Description

IPC Request Bus:

Re que st Strob e Input This inp ut sig nifie s a v alid inp ut re q ue st and signals the start o f an IP C o p eratio n cycle .

Command

Bus

Instruction Input These two fields of the Command bus define the instruction to be performed by the IPC and the lookup

type . The lo ok up ty pe is se le cte d only for op e ratio nal type comm and s (Lo o kup s, Le arns) and is a "d on't

care " fo r m ainte nance ty p e command s (all Read s and Write s).

Lookup Type Input

Global Mask

Register Select Input This field is within the Command bus. During Lookup or Write operations, this field defines which of the

Global Mask Register groups are b eing accessed. This field is a "don't care" for Read, SRAM No Wait

Re ad, and Le arn Op eratio ns.

Co mp arand and

Result Re gister

Select Input This is a multiplexed field within the Command Bus that specifies both the Result Register to store the

Inde x into , and the C o mp arand Re gister to use . This fie ld is samp le d e very inp u t c lo ck cycle . The first

cycle decodes the selected Comparand Register and the second decodes the selected Result Register.

Request Data Bus Input/Output

Three State The Re quest Data Bus is a multiplexe d add ress/data bus used to perform re ads (a nd writes) from (to) the

IPC, and to p re se nt se arch d ata for lo okups .

IPC Response Bus:

Ind e x Bus

Address Output

Thre e State

This b us is us ed to driv e the ad d re ss of an e xte rnal SRA M, o r fe e db ack Loo kup result informatio n

directly to the IPC's ASIC/FPGA. The Index Bus contain the encoded location at which the compare was

found, the address of the IPC which found the result and the Lookup type.

De v ic e ID

Lo ok up Ty pe

Chip Enab le / Output Enab le Output

Three State This signal is driven along with the Index Bus. It is connected to the CE i np u t p in o f a ZBT S RA M o r to the

OE p in o f a PB SRAM.

Write Enab le Output

Thre e State This signal is driven along with the Index bus. It is used to assert the WE

pin of an external SRAM. It is

active for b oth SRAM write op e ratio ns and the Le arn co mmand.

Read Acknowledge Output Thi s s ignal is se nt b ac k when the d ata is re ad from the IP C o n the Req u e s t Data B us , o r whe n th e d ata

b e ing re ad fro m the assoc iated external SRAM.

Match Acknowledge Output This is signal is sent with the Index. It will be driven low if there was no match, high if a match was found.

Valid

Lo ok up Bit Output This signal is sent with the Index. It will be driven high upon the completion of a lookup, even if the

lo o kup did no t re s ult in a hit.

Multi Match

Output Output

(Op e n Drain)

This signal is sent with the Index. It shall go active when a) multiple hits occur in one segment; or, b) one

o r more hits o ccur in two (o r mo re) se g me nts ; o r, c) o ne o r mo re hits o ccur in multip le d e vic es that are

depth cascaded.

Depth Expansion:

De vic e Ad dre ss Inp ut These three DC pins are used to define the Device Address for each of the eight possible depth

expanded IPC dev ices in an IPC system.

Match

Input Input The Match Inp ut s ig nal i s d riv en b y all up stream Match Output sig nals . This ind ic a te s to all d o wn s tre am

IPCs that a hit in a hig he r p rio rity IPC has occurre d.

Match

Output Output The M atch Outp ut s ig nal s ig nifie s that a matc h has oc curre d in the IPC. The sig nal is fe d into a Matc h

Input line o f all l ower p rio rity IPC(s).

Clock and I nitiali zation:

Clock Input Input All inputs and outputs are referenced to the positive edge of this clock.

Clo ck Phas e Enab le Input This sig nal is use d to ge ne rate an inte rnal clo ck at ½ the fre quenc y of the input clo ck.

Re se t Input This p in wil l force all outp uts to a high imp e de nce co nd itio n, as well as cle ar ing the IPC e nab le b it.

Advanc e Burst Ad dres s Input This sig nal will advanc e an inte rnal ad d ress c ounter to allo w for b urst write s when writing to the Data/Mas k

me mory in the IPC. This p rovides a m ec hanism to co nvenie ntly initialize the IPC memory.

Last IPC Input This pin defines which IPC device will drive the ASIC Feedback signals to the ASIC/FPGA.

Las t SRAM Input Thi s p in d e fine s which IPC d evice will d riv e the SRAM c o ntro l s ig nals CE/OE and WE. It als o d efaults

this device to driving the Index Bus when there is no ongoing operation preventing the bus from floating.

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