December 1994 Order Number: 290479-004
82434LX/82434NX PCI, CACHE AND MEMORY
CONTROLLER (PCMC)
Y
Supports the Pentium
TM
Processor at
iCOMP
TM
Index 510T60 MHz and iCOMP
Index 567T66 MHz
Y
Supports the Pentium Processor at
iCOMP Index 735T90 MHz, iCOMP Index
815T100 MHz, and iCOMP Index 610T75
MHz
Y
Supports Pipelined Addressing
Capability of the Pentium Processor
Y
The 82430NX Drives 3.3V Signal Levels
on the CPU and Cache Interfaces
Y
High Performance CPU/PCI/Memory
Interfaces via Posted Write and Read
Prefetch Buffers
Y
Fully Synchronous PCI Interface with
Full Bus Master Capability
Y
Supports the Pentium Processor
Internal Cache in Either Write-Through
or Write-Back Mode
Y
Programmable Attribute Map of DOS
and BIOS Regions for System
Flexibility
Y
Integrated Low Skew Clock Driver for
Distributing Host Clock
Y
Integrated Second Level Cache
Controller
— Integrated Cache Tag RAM
— Write-Through and Write-Back Cache
Modes for the 82434LX
— Write-Back for the 82434NX
— 82434NX Supports Low-Power Cache
Standby
— Direct Mapped Organization
— Supports Standard and Burst SRAMs
— 256-KByte and 512-KByte Sizes
— Cache Hit Cycle of 3-1-1-1 on Reads
and Writes Using Burst SRAMs
— Cache Hit Cycle of 3-2-2-2 on Reads
and 4-2-2-2 on Writes Using
Standard SRAMs
Y
Integrated DRAM Controller
— Supports 2 MBytes to 192 MBytes of
Cacheable Main Memory for the
82434LX
— Supports 2 MBytes to 512 MBytes of
Cacheable Main Memory for the
82434NX
— Supports DRAM Access Times of
70 ns and 60 ns
— CPU Writes Posted to DRAM 4-1-1-1
— Refresh Cycles Decoupled from ISA
Refresh to Reduce the DRAM
Access Latency
— Six RAS Lines (82434LX)
— Eight RAS Lines (82434NX)
— Refresh by RAS -Only, or CAS-
Before-RAS , in Single or Burst
of Four
Y
Host/PCI Bridge
— Translates CPU Cycles into PCI Bus
Cycles
— Translates Back-to-Back Sequential
CPU Memory Writes into PCI Burst
Cycles
— Burst Mode Writes to PCI in Zero PCI
Wait-States (i.e. Data Transfer Every
Cycle)
— Full Concurrency Between CPU-to-
Main Memory and PCI-to-PCI
Transactions
— Full Concurrency Between CPU-to-
Second Level Cache and PCI-to-Main
Memory Transactions
— Same Cache and Memory System
Logic Design for ISA and EISA
Systems
— Cache Snoop Filter Ensures Data
Consistency for PCI-to-Main Memory
Transactions
Y
208-Pin QFP Package
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