21050 PCI-to-PCI Bridge
Brief Datasheet
Product Features
Intel's 21050 is a low-cost, high-performance bridge that expands the electrical
capacity of PCI based systems.
I
s
Complies fully with Revision 2.0 of the
PCI Local Bus Specification
s
Operates at a maximum frequency of
33 MHz
s
Provides master latency timers and target
wait timers that limit the amount of latency
on either bus
s
Provides concurrent primary and secondary
bus operation
s
Provides I/O transaction filtering through
one programmable memory I/O address
region
s
Provides ISA-awareness for I/O transaction
filtering
s
Supports two 32-bit PCI buses
s
Provides pins for buffer empty status and
write-posting control
s
Provides memory transaction filtering
through two programmable memory
address regions--one prefetchable and one
non-prefetchable
s
Provides dual-address transaction
forwarding in the upstream direction
s
Provides read prefetching for memory read
transactions
s
Supports seven secondary bus clock
outputs
s
Provides up to eight dwords (32 bytes) of
write posting in both directions for memory
write transactions
s
Supports forwarding of video graphics
adapter (VGA) memory and I/O addresses,
and snooping of VGA palette I/O writes
s
Supports perr and serr signals with error-
checking functionality
s
Propagates locks across the bridge
s
Provides concurrent resource lock
operation
s
Provides programmable rotating arbiter
supporting up to six secondary bus masters
-- Can be disabled through the s_cfn_l
input pin
s
Conditionally forward the following
transactions:
-- All memory read and write transactions
in either direction
-- I/O read and write transactions in either
direction
-- Configuration read and write
transactions in the downstream direction
-- Configuration write transactions to
special cycles in either direction
Order Number: 278140-001
October 1998
2
Brief Datasheet
Description
The 21050 allows motherboard designers to add more PCI devices or more PCI
option card slots than a single PCI bus can support. Option card designers can
use the 21050 to implement multiple-device PCI option cards. The 21050 can
also isolate traffic between devices on one PCI bus from devices on the other PCI
buses. This traffic isolation may increase system performance in applications
such as multimedia.
An evaluation and development board is available for developers to develop
software for the 21050 and evaluate its functionality.
Applications
The 21050 makes it possible for the PCI bus to expand its electrical capacity by
allowing additional PCI devices and PCI option card slots.
Figure 1
, the system
card block diagram illustrates the use of two PCI-to-PCI bridges on a system
board. Each 21050 added to the board creates a new PCI bus that provides
additional support for the additional PCI slots or devices.
Information in this document is provided in connection with Intel products. No license, express or implied, by estoppel or otherwise, to any intellectual
property rights is granted by this document. Except as provided in Intel's Terms and Conditions of Sale for such products, Intel assumes no liability
whatsoever, and Intel disclaims any express or implied warranty, relating to sale and/or use of Intel products including liability or warranties relating to
fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. Intel products are not
intended for use in medical, life saving, or life sustaining applications.
Intel may make changes to specifications and product descriptions at any time, without notice.
Contact your local Intel sales office or your distributor to obtain the latest specifications and before placing your product order.
Copies of documents which have an ordering number and are referenced in this document, or other Intel literature may be obtained by calling 1-800-
548-4725 or by visiting Intel's website at http://www.intel.com.
Copyright Intel Corporation, 1998
*Third-party brands and names are the property of their respective owners.
21050 PCI-to-PCI Bridge
4
Brief Datasheet
Multidevice PCI Option Cards
The 21050 allows the PCI bus to support multiple components on option cards. Option cards are
restricted to a single connection per PCI signal in the PCI Local Bus Specification.
Figure 2
, the
21050 with option cards diagram illustrates how the 21050 enables the design of a multicomponent
option card.
Figure 2. 21050 with Option Cards
A4913-01
LAN
Chip
21050
PCI Bus
PCI Bus
LAN
Chip
LAN
Chip
LAN
Chip
Characteristics
Specifications
Power supply
V
ss
0.0 V, V
dd
5 V 5%
Operating temperature
Tj maximum = 100C
Storage temperature range
55C to +125C (67F to 257F)
Power dissipation (typical)
1.7 W maximum
Package
208-pin PQFP
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