ETC PC87550

February 1997
PC87550
PicoPower North Bridge—PCI System Controller
General Description
A high-performance, highly integrated system controller for
Microsoft ® Windows ® -compatible computers, the PC87550
significantly improves upon the performance offered by current system-logic solutions. The PCI-based system controller is optimized for portable multimedia systems with critical
form-factor and power consumption requirements.
The PC87550 supports full PCI, DRAM, CPU, and L2-cache
concurrency. It achieves a more effective utilization of the
CPU bus by allowing the CPU execution to continue while
the PCI Master is accessing the DRAM.
The presence of two independent write buffers improves performance by allowing PCI memory writes and DRAM
memory writes/reads to occur concurrently. The PC87550
also supports the concurrent operation of an external PCI
Master and a Pentium processor.
The PC87550 supports sustained PCI bursting of up to 120
Mbytes per second. It can achieve a sustained burst rate of
x-1-1-1-1.... for both CPU-to-PCI and PCI Master-to-DRAM
accesses.
The PC87550 system controller integrates the following
functions in a single 388-pin BGA package:
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CPU-to-PCI bus interface controller/arbiter
L2-cache controller
DRAM controller
Power management controller
Data path controller
SmartDock™ and SmartDock-II hot-docking interface
The level-2 cache controller supports synchronous burst,
and pipelined synchronous SRAM.
It supports cache sizes ranging from 256 Kbytes to 512
Kbytes. Additionally, buffered write-through cache update
schemes allow further performance gains by not stalling the
CPU on L1 writeback cycles.
A sophisticated DRAM controller supports leading-edge 3.3V
DRAM technologies. Support for synchronous DRAM allows
the PC87550 to achieve improved performance in a cacheless system configuration. The DRAM controller implements
the logic required to use high-speed DRAM, reducing the
performance overhead of the L2-cache miss cycles. It provides a synchronous interface between the CPU and PCI
buses to exploit the maximum potential of the PCI bandwidth.
Active and passive power management features enable systems with superior power and thermal management.
PC87550 supports both legacy and Advanced Configuration
and Power management Interface (ACPI) implementations.
A special thermal control mechanism uses CPU clock throt-
tling to efficiently control the power consumption and heat
dissipation associated with the processor. An innovative programming model simplifies the BIOS development task without compromising any of the power management features.
The PC87550 provides a 32- or 64-bit data path between the
CPU and the main memory; a 32-bit data path between the
CPU bus and the PCI Local bus; and a 32-bit data path between the PCI Local bus and the main memory.
PC87560 PCI system I/O controller complements the
PC87550 solution by providing a highly integrated bridge between the PCI and ISA buses. Both devices contain the necessary logic to support master and slave cycles on both PCI
and ISA buses.
To enable a full-featured docking station design, the
PC87550 provides all the hooks required to support PCI hotwarm-, and cold-docking. It is fully optimized to work with
PC87560 and the NILE II devices to support a full secondary
ISA bus in the PCI docking station, thus allowing PCI and
ISA slots in the docking station. The PC87550 also implements the docking interface control logic to enable port replicator dock and PCI hot-, warm-, and cold-docking. This interface provides a seamless support for docking without
requiring external logic.
To enable a full-featured docking station design, the
PC87550 provides all the hooks required to support PCI hotwarm-, and cold-docking. It is fully optimized to work with
PC87560 and the NILE II devices to support a full secondary
ISA bus in the PCI docking station, thus allowing PCI and
ISA slots in the docking station. The PC87550 also implements the docking interface control logic to enable port replicator dock and PCI hot-, warm-, and cold-docking. This interface provides a seamless support for docking without
requiring external logic.
The 388-pin BGA packaging offers a sleek, durable package
with good thermal properties and noise immunity. The device
comes with full technical and hardware support, including
samples, evaluation boards, and design examples.
PC87550 PicoPower North Bridge—PCI System Controller
PRELIMINARY
Features
n Optimized single-chip PCI system controller for Intel ®
Pentium ® processors
— Processor bus speeds of 50-, 60-, and 66-MHz
— Supports 5-class processors from AMD ® and Cyrix ®
— Supports processors with 3.2V or 2.5V CPU bus
interface
— Supports level-1 write-back or write-through cache
— Supports both toggle and linear burst sequences
— Supports CPU address pipelining
— Optimized for Multimedia Extension (MMX)
processors
Intel ® is a registered trademark of Intel Corporation.
Pentium ® is a registered trademark of Intel Corporation.
Microsoft ® is a registered trademark of Microsoft Corporation.
Windows ® is a registered trademark of Microsoft Corporation.
AMD ® is a registered trademark of Advanced Micro Devices, Inc.
Cyrix ® is a registered trademark of
SmartDock™ is a trademark of
© 1997 National Semiconductor Corporation
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Features
− PCI-to-DRAM write/read burst
— Twenty-four D-word PCI-to-DRAM write buffer
— Sixteen D-word pre-fetch read buffer
— Five PCI REQ#/GNT# pairs for PCI Master support
— Supports PCI Bus speeds up to 33 MHz
— Supports 3.3V I/O, 5V-tolerant 32-bit PCI local bus
— Synchronous interface between the CPU and PCI
Bus
— Complies with PCI Local Bus revision 2.1
— Integrated PCI Bus arbiter with configurable priority
schemes
— PCI parity and system error support
— PC87560 PCI System I/O controller provides a
complete solution
n Power and thermal management
— Complies with ACPI and Windows 95 APM 1.2
— Active and passive power management cuts power
consumption when the system is in use or in an idle
state
— Supports both legacy and ACPI power management
implementations
— Supports System Management Mode (SMM), System
Management Interrupt (SMI), Stop Clock, and
AutoHalt
— 3.3V voltage implementation
— Thermal control with thermal clock throttling (optional)
— User-programmable power setting
— Supports wakeup control, interrupt-aswakeup-source, and ring-input-as-wakeup source
— Power management registers are fully compatible
with the VESUVIUS-LS system controllers
— External activity detection and status indicator
— Supports 3.3V and 2.5V processor bus, 3.3V
(5V-tolerant) PCI bus, 3.3V L2 cache controller, and
3.3V (5V-tolerant) DRAM subsystem
n Advanced docking support
— Hot-, warm-, or cold- PCI docking support
— Proprietary SmartDock and SmartDock-II hot-docking
arbitration interface
— Supports DDMA and serialized IRQ (SERIRQ) open
specifications for dual-ISA bus support and lowers
the docking connector pin count
n Technology
— Supports JTAG boundary scan
— Space-efficient 388-pin BGA package
— 0.5 µm CMOS technology
(Continued)
n 64-bit direct-mapped, write-through L2-cache controller
— Supports either a cacheless configuration or cache
sizes of 256 Kbytes to 512 Kbytes with a 32-byte line
size
— Supports synchronous burst and pipelined burst
SRAM
— Supports 5V TAG RAM
n State-of-the-art DRAM controller
— 4 Mbytes to 256 Mbytes of system memory
— Supports 3.3V/5V Fast Page Mode (FPM), Extended
Data Output (EDO), and Synchronous DRAM
(SDRAM) in the mixed mode with auto-detect
capability
— Allows mixing of 64- and 32-bit DRAM in
non-SDRAM banks
— Supports up to 6 banks of 64-bit DRAM/SDRAM or
12 banks of 32-bit DRAM (non-SDRAM)
— Supports two concurrent write buffers—one 8-level,
64-bit DRAM write-buffer and one 16-level 32-bit PCI
write buffer
− Supports 2-1-1-1 burst write (CPU bus)
− Supports read reordering
— Supports 512 Kbit, 1 Mbit, 2 Mbit, 4 Mbit, 16 Mbit,
and 64 Mbit symmetric or asymmetric DRAM
— Slow/self-refresh support, including hidden,
staggered, CAS-before-RAS refresh or RAS-only
refresh
— Supports sustained bursting of 1-1-1-1 for
Synchronous DRAM (SDRAM) for CPU pipelined
back-to-back cycles with hidden lead-off
− 6-2-2-2 burst read cycles with 60 ns EDO DRAM at
66 MHz
− 6-1-1-1 burst read cycles with SDRAM
− 6-3-3-3 page-hit and 10-3-3-3 page-miss burst-read
cycles with 60 ns standard DRAM at 66 MHz
— SMM RAM size from 32 Kbyte to 128 Kbyte. Easy
SMI code copying to SMM RAM in normal memory
mode
n Full PCI, DRAM, and CPU concurrency
— Concurrent CPU-to-L2 and PCI-to-DRAM operation
— Concurrent CPU-to-DRAM and PCI Master-to-PCI
Target peer transfer
n PCI Local Bus interface
— Supports sustained PCI bursting up to 120 Mbytes
per second
− CPU-to-PCI burst write
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AMAZON System Block Diagram
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Typical Portable Computer Design with Zero-Volt Suspend Implementation
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LEGEND
V = VCC SUSP_ON/OFF
CC = Charger Control
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PC87550 PicoPower North Bridge—PCI System Controller
Physical Dimensions
inches (millimeters)
LIFE SUPPORT POLICY
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2. A critical component in any component of a life support
1. Life support devices or systems are devices or sysdevice or system whose failure to perform can be reatems which, (a) are intended for surgical implant into
sonably expected to cause the failure of the life support
the body, or (b) support or sustain life, and whose faildevice or system, or to affect its safety or effectiveness.
ure to perform when properly used in accordance
with instructions for use provided in the labeling, can
be reasonably expected to result in a significant injury
to the user.
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