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MU9C3480L-12DC

LANCAM®

Music Semiconductors 

®MUSICI

SEMICONDUCTORS

MU9C3480L

LANCAM®

PRELIMINARY DATA SHEET DRAFT

DISTINCTIVE CHARACTERISTICS

• 256 x 64-bit CMOS Content-addressable Memory (CAM)

with 16-bit I/O for compatibility with the MU9C5480L

• Dual configuration register set (Control, Segment

Control, Mask Register 1, Address Register, and

Persistent Source and Destination) for rapid context

switching

• Shiftable Comparand and Mask Register 2 to assist in

proximate matching algorithms

• Increased flexibility of the patented CAM/RAM

partitioning

• Added /MA and /MM output flags to enable faster

system performance

• Readable Device ID

• Selectable faster operating mode with no wait states

after a no-match

• Validity bits of entries are stored in the Status register

after a read or move from memory operation

• Single cycle reset for Segment Control register

• Packaged in an industry-standard 44-pin PLCC

package to be socket compatible with the MU9C5480L

and MU9C1480L

• Single 3.3 Volt Supply for low power operation

BLOCK DIAGRAM

DQ (15–0)

(16)

DATA (16)

MUX

DATA (64)

DATA (16)

TRANSLATE

802.3/802.5

DATA (16)

DEMUX

DATA (64)

LEGEND

VCC

GND

* = DEFAULT

W/O = WRITE ONLY

R/O = READ ONLY

= LOGIC

= REGISTERS

AND MEMORY

COMMANDS & STATUS

(16)

SOURCE AND

DESTINATION

SEGMENT

COUNTERS

COMPARAND*

MASK 1

MASK 2

/E

INSTRUCTION (W/O)*

/W

ADDRESS ADDRESS

CONTROL

8

NEXT FREE ADDRESS (R/O)

/CM

CONTROL

/RESET

/EC

SEGMENT CONTROL

16

PAGE ADDRESS (LOCAL)

DEVICE SELECT (GLOBAL) MATCH ADDR

& /MA FLAG

9

STATUS (15-0) (R/O)*

/MM, /FL

2

STATUS (31-16) (R/O)

REGISTER SET

CAM ARRAY

256 WORDS

X 64 BITS

/MA

/MM

2

/FF

MATCH

/FI

AND

FLAG

LOGIC

/MF

/MI

GENERAL DESCRIPTION

The MU9C3480L LANCAM is a 256 x 64-bit Content-

addressable Memory (CAM), designed for address filtering

applications in Local-area Network (LAN) bridges, routers, and

switches needing a 3.3 volt CAM. The architecture of the

LANCAM allows a network station list of any length to be

searched in a single memory transaction. This device is also

well-suited for other high-speed data search applications such

as virtual memories, optical and magnetic disk caches, data

base accelerators, data compressors, and image processors.

Content-addressable Memories, also known as Associative

Memories, operate in the converse way to Random Access

Memories. In a RAM, the input to the device is an address, and

the output is the data stored at that address. In a CAM, the input

is a data sample and the output is a flag to indicate a match and

the address of the matching data. As a result, a CAM searches

large data bases for matching data in a short, constant time

period, no matter how many entries are in the data base. The

ability to search data words up to 64 bits wide allows large

address spaces to be searched rapidly and efficiently. A

patented architecture links each CAM entry to associated data

and makes this data available for use after a successful

compare operation.

LANCAM, the MUSIC logo, and the phrase “MUSIC Semiconductors” are registered trademarks of MUSIC Semiconductors.

MUSIC is a trademark of MUSIC Semiconductors. Certain features of this device are patented under US Patent 5,383,146.

15 April 1997 Rev. 1.0 Draft Web

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