MU9C RCP Family

Rev. 8.04

3

Figure 2: Switch Block Diagram

PIN DESCRIPTIONS

Note: Signal names that start with a slash ("/") are active LOW. All signals are 3.3V CMOS level. Never leave inputs floating. The CAM

architecture draws substantial currents during compare operations, mandating the use of good layout and bypassing techniques. Refer

to the Electrical Characteristics section for more information.

DQ31-0 (Data Bus, Three-state, Common

Input/ Output)

The DQ31-0 lines convey data to and from the MU9C

RCP. When the /E input is HIGH the DQ31-0 lines are

held in their high-impedance state. The /W input deter-

mines whether data flows to or from the device on the

DQ31-0 lines. The source or destination of the data is

determined by the AC bus, DSC, and the /AV line. During

a Write cycle, data on the DQ31-0 lines is registered by the

falling edge of /E.

AC12-0/AC11-0 (Address/Control Bus, Input)

When Hardware control is selected, the AC bus conveys

address or control information to the MU9C RCP, depend-

ing on the state of the /AV input. When /AV is LOW then

the AC bus carries an address; when /AV is HIGH the AC

bus carries control information. Data on the AC bus is reg-

istered by the falling edge of /E. When software control is

selected, the state of the AC bus does not affect the opera-

tion of the device.

DSC (Data Segment Control, Input)

When DQ bus access to a 64 bit register or memory word

is performed, the DSC input determines whether bits 31-0

(DSC LOW) or bits 63-32 (DSC HIGH) are accessed.

Access to 32 bit registers require that DSC be held LOW.

AA12-0/AA11-0 (Active Address, Output)

The AA bus conveys the Match address, the Next Free

address, or Random Access address, depending on the

most recent memory cycle. The /OE input enables the AA

bus; when the /OE input is HIGH, the AA bus is in its

high-impedance state; when /OE is LOW the AA bus is

active. In a vertically cascaded system after a Comparison

cycle, Write at Next Free Address cycle or Read/Write at

Highest-Priority match, only the highest-priority device

will enable its AA bus, regardless of the state of the /OE

input. In the event of a mismatch in the Address Database

after a Compare cycle, or after a Write at Next Free

Address cycle into an already full system, the lowest-pri-

ority device will drive the AA bus with all 1s. The AA bus

is latched when /E is LOW, and are free to change only

when /E is HIGH.

Controller

Sw itch

Fabric

MU 9C

RAM

Sw itch C ontrol

And Packet

Data

P acket Stream

RC P

Control

Network

Address

RAM

A ddress

Data

Controller

Sw itch

Fabric

MU 9C

RAM

Sw itch C ontrol

And Packet

Data

P acket Stream

RC P

Control

Network

Address

RAM

A ddress

Data