Chipset; 82441Fx Pci Bridge And Memory Controller (Pmc); 82442Fx Data Bus Accelerator (Dbx); 82371Sb Pci/Isa Ide Xcelerator (Piix3) - Intel VS440FX Technical Specification

1.7 Chipset

The Intel 82440FX PCIset consists of the 82441FX PCI Bridge and Memory Controller (PMC),
the 82442FX Data Bus Accelerator (DBX), and one 82371SB PCI/ISA IDE Xcelerator (PIIX3)
bridge chip.

1.7.1 82441FX PCI Bridge and Memory Controller (PMC)

The PMC provides all control signals necessary to drive second level cache and main memory,
including multiplexed address signals. It also controls system access to memory and generates
snoop controls to maintain cache coherency. The PMC comes in a 208-pin QFP package that
features:
Microprocessor interface control
Integrated L2 write-back cache controller
256 or 512 KB direct-mapped
Integrated DRAM controller
64/72-bit non-interleaved path to memory
EDO and fast page DRAM support
Non-parity, parity, and ECC support
Fully synchronous PCI bus interface
30 and 33 MHz bus speeds
PCI to DRAM data throughput at greater than 100 MB per second
Up to four PCI masters in addition to the PIIX3 and IDE
Data Buffering
Pentium Pro processor-to-DRAM and PCI-to-DRAM write data buffering
Pentium Pro-processor-to-PCI burst writes

1.7.2 82442FX Data Bus Accelerator (DBX)

The DBX connects to the 64-bit Pentium Pro data bus, the 64/72-bit memory data bus, and the
16 bit PMC private data bus. The DBX works in parallel with the PMC to provide a high
performance memory subsystem for Pentium Pro processor based systems. The DBX comes in a
208-pin QFP package.
1.7.3

82371SB PCI/ISA IDE Xcelerator (PIIX3)

The PIIX3 is the interface between the PCI and ISA buses. It features an integrated dual-channel
enhanced IDE interface that supports up to four IDE devices. The PIIX3 comes in a 208-pin QFP
package that features:
PCI and ISA bus interface
USB host/hub controller
Motherboard Description
13