®
S E M I C O N D U C T O R S
MUSIC
I
MU9C8148
SRT Interface
DATA SHEET DRAFT
DISTINCTIVE CHARACTERISTICS
• Supports High-speed Source Routing or Source Routing
Transparent Bridging for up to eight ports
• Glue-free operation with the MUSIC MU9C1480 LANCAM
and Texas Instruments’ Token Ring chip set
• Configurable for either Motorola or Intel processor
addressing modes
• Complies with the IEEE standards for 4 and 16 Mb/s
Token Ring
• Contains a 128-entry Instruction Buffer that holds up to
seven down-loadable filtering and purging routines,
which can be automatically or directly invoked
• Automatically selects Source Routed or Transparent
filtering routines based on Transceiver output data, and
supplies the proper Match, Fail, or Flush signals to the
MAC chips
• Built-in arbitration allows two MU9C8148s to share a
central LANCAM database
• Selectable filtering options for each frame type
• Frame validity is checked on all Routing Information
Fields
• Manufactured in CMOS technology
• Available in 68-pin PLCC package and 80-pin TQFP
package
The MU9C8148 can choose to copy or reject a frame depending on the
frame type (MAC, LLC, or reserved), and can perform multiple validity
checks on the Routing Information Field (RIF), including general checks
on every Routing Control Field (RCF), as well as multiple frame related
checks.
The Instruction Buffer can be loaded with up to 128 instructions at
initialization for the LANCAM routines such as matching, learning,
aging, purging, and data buffering operations. Internal arbitration
controls access to the LANCAM. Separate arbitration pins allow two
MU9C8148s to easily form a dual-port Bridge by sharing a central
LANCAM-based station list.
With seven Ring-Bridge-Ring number combinations stored internally,
the MU9C8148 can also operate as a source routing accelerator in
multi-port Token Ring Bridge/Brouter environments.
GENERAL DESCRIPTION
The MU9C8148 is a Source Routing Transparent (SRT) Interface for
the MUSIC Semiconductors MU9C1480 LANCAM for use in Token
Ring LAN Bridges and Brouters. This interface operates in accordance
with IEEE standards while supporting address filtering rates up to
150,000 frames/sec for minimum-length frames.
The MU9C8148 has four interfaces to provide glue-free address
filtering. The Transceiver interface monitors receive data from the
Transceiver to the MAC, and determines whether to filter according to
Source Routing or Transparent Bridging standards. The MAC interface
supplies Match, Fail, and Flush signals to instruct the Token Ring
controller to reject or copy a frame. The LANCAM interface controls the
companion LANCAM(s) for Transparent filtering. The Host Processor
interface allows for direct initialization of the MU9C8148, and
downloading of the filtering and purging routines, to offload the
communication processor.
BLOCK DIAGRAM
/RDY
RXD
RXC
XMATCH
XFAIL, /FLUSH
TRANSCEIVER
INTERFACE
MAC
INTERFACE
/INT
DQ15-DQ0
16
LANCAM INTERFACE
5
TRANSPARENT
BRIDGING BLOCK
HOST PROCESSOR
INTERFACE
16
A4-A0
D15-D0
ALE, SRNW
/CS
/RS, /LDS
/WS, /UDS
/HBRDY
/HBEN
/HBDIR
/RESET
/FULL, /EMPTY
/E
/W
/CM
/EC
/MI
/FI
SOURCE ROUTING
BLOCK
INSTRUCTION
BUFFER
ARBITER
/RQ
/RQI
/INTEL
15 April 1997 Rev. 5.5 Draft
Web
LANCAM, the MUSIC logo, and the phrase “MUSIC Semiconductors” are registered trademarks of MUSIC Semiconductors. MUSIC is a trademark
of MUSIC Semiconductors. This device takes advantage of features in the LANCAM patented under U.S. Patent 5,383,146.
MUSIC [ MUSIC SEMICONDUCTORS ]
