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1.6.2 82430VX Data Path (TDX)
Two 82430VX TDX data path components provide a 64-bit microprocessor to memory path. The
TDX components are controlled by the TVX. They each add one load to the PCI bus and perform
all of the required byte and word swapping. The TDX devices come in a 208 pin QFP package.
1.6.3 PCI ISA/IDE Xcelerator (PIIX3)
The PIIX3 provides the interface between the PCI and ISA buses and integrates a dual channel fast
IDE interface capable of supporting up to 4 devices. The PIIX3 integrates seven 32-bit DMA
channels, five 16-bit timer/counters, two eight-channel interrupt controllers, PCI-to-AT interrupt
mapping circuitry, NMI logic, ISA refresh address generation, and PCI/ISA bus arbitration
circuitry together onto the same device. The PIIX3 comes in a 208-pin QFP package that features:
• PCI Bus and ISA Bus interface
• Universal Serial Bus controller
Host/hub controller
• Integrated fast IDE interface
Support for up to 4 devices
PIO Mode 4 transfers up to
16 MB/sec
Integrated 8 x 32-bit buffer for
bus master PCI IDE burst
transfers
Bus master mode
• PCI 2.1 compliance
• Enhanced fast DMA controller
• Interrupt controller and steering
• Counters/timers
• SMI interrupt logic and timer with
fast on/off mode
1.6.4 IDE SUPPORT
The motherboard provides two independent bus-mastering PCI IDE interfaces that support PIO
Mode 3 and Mode 4 devices. The system BIOS supports Logical Block Addressing (LBA) and
Extended Cylinder Sector Head (ECHS) translation modes as well as ATAPI (e.g. CD-ROM)
devices on both IDE interfaces. The system BIOS automatically detects IDE device transfer rate
and translation mode.
Normally, programmed I/O operations require a substantial amount of CPU bandwidth. In true
multi-tasking operating systems like Windows† 95, the CPU bandwidth freed up by using bus
mastering IDE can be used to complete other tasks while disk transfers are occurring. When used
in conjunction with the appropriate driver for the Windows 95 environment, the IDE interface can
operate as a PCI bus master capable of supporting PIO Mode 4 devices with transfer rates of up to
16 MB/sec.