Product specifications
ProSavageDDR P4M266 – VT8751 P4 DDR SMA North Bridge
Revision 1.1, July 19, 2002 -4- Overview
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OVERVIEW
The ProSavageDDR P4M266 (VT8751 North Bridge plus VT8233 South Bridge) is a high performance, cost-effective and energy
efficient SMA chip set for the implementation of desktop personal computer systems with 400 MHz (100 MHz QDR) CPU host
bus (“Front Side Bus”) based on 64-bit Intel Pentium-4 super-scalar processors. This data sheet describes the VT8751 North
Bridge portion of the P4M266 chipset (except for detailed register descriptions for the integrated graphics controller which are
described in a separate document published by S3 Graphics). The VT8233 South Bridge is described in a separate data sheet.
Figure 1. P4M266 Chipset System Block Diagram
The ProSavageDDR P4M266 chipset consists of the VT8751 DDR SMA North Bridge (664 pin BGA) and the VT8233 V-Link
South Bridge (376 pin BGA). The VT8751 (which may also be referred to as a “Host System Controller”) integrates VIA’s
VT8653 Apollo Pro266T system controller with CPU bus extensions to support Pentium 4, S3 Graphics’ 128-bit ProSavage8
2D/3D graphics accelerator and S3 Graphics’ flat panel monitor and TV out interfaces into a single 664 BGA package. The
VT8751 provides superior performance between the CPU, DRAM, V-Link bus and internal or external AGP 4x graphics controller
bus with pipelined, burst, and concurrent operation. The VT8233 South Bridge (which may also be referred to as a “V-Link Client
Controller”) is a highly integrated PCI / LPC controller. Its internal bus structure is based on 66 MHz PCI bus that provides 2x
bandwidth compare to previous generation PCI bridge chips. The VT8233 also provides a 266MB/sec bandwidth Host/Client V-
Link interface with V-Link-PCI and V-Link-LPC controllers. It supports five PCI slots of arbitration and decoding for all
integrated functions and LPC bus.
The VT8751 supports eight banks of SDR / DDR SDRAMs up to 4 GB. The DRAM controller supports PC2100 / PC1600
Double-Data-Rated (DDR) SDRAM but can also support standard PC133 / PC100 Synchronous DRAM (SDR SDRAM). The
DDR / SDR DRAM interface allows zero wait state bursting between the DRAM and the data buffers at 100 / 133 MHz. The
different banks of DRAM can be composed of an arbitrary mixture of 1M / 2M / 4M / 8M / 16M / 32M / 64M x 8/16/32 DRAMs.
The DRAM controller also supports optional ECC (single-bit error correction and multi-bit detection) or EC (error checking)
capability. The DRAM controller can run either synchronous or pseudo-synchronous with the host CPU bus.
The VT8751 host system controller supports a high speed 8-bit 66 MHz Quad Data Transfer interconnect (V-Link) to the VT8233
South Bridge. The chip also contains a built-in bus-to-bus bridge to allow simultaneous concurrent operations on each bus. Five
levels (doublewords) of post write buffers are included to allow for concurrent CPU and V-Link operation. For V-Link Host
operation, forty-eight levels (doublewords) of post write buffers and sixteen levels (doublewords) of prefetch buffers are included
for concurrent V-Link bus and DRAM/cache accesses. When combined the V-Link Host / Client controllers, it realizes a complete
PCI sub-system and supports enhanced PCI bus commands such as Memory-Read-Line, Memory-Read-Multiple and Memory-
Write-Invalid commands to minimize snoop overhead. In addition, advanced features are supported such as snoop ahead, snoop
filtering, L1 write-back forward to PCI master, and L1 write-back merged with PCI post write buffers to minimize PCI master read
latency and DRAM utilization. Delay transaction and read caching mechanisms are also implemented for further improvement of
overall system performance.
TV
Encoder
400 MHz
(100 MHz QDR)
FSB
64-bit 133/100 MHz DDR or SDR / ECC
33MHz,
32-bit
PCI
6X USB
AC-Link
LPC
ProSavage P4M266
Chipset
VT8233 or VT8233C
V-Link
South Bridge
376-pin PBGA
VT1 616
AC'97 Audio Codec
MC-97
Modem Codec
UDMA / ATA
33 / 66 / 100
Integrat ed
AC'97 Audio
PCI Slots
VT6103
Network
Interface PHY
VT1211
LPC
Super
I/O
4x
AGP
Slot
Flat Panel Monitor
ProSavage P4M266
Chipset
VT8751
Pentium 4 DDR SMA
North Bridge
664-pin PBGA
CRT
Pentium
4
CPU
Keyboard
66MHz QDR, 8-bit V-Link
System
Management
Bus
10/100 Ethernet
12-bit DVI
Or TV Out
EPROM
Serial / IR
Parallel
Floppy Disk
Direct
Or LPC
MII
Mouse