Chapter 2. System-Board Features
bus. The chip set is capable of supporting PIO mode 0–4 devices and IDE DMA mode 0–2 devices, ultra
DMA 33 transfers up to 33 Mbytes/sec.
The IDE devices receive their power through a four-position power cable cont5 V dc, +12 V dc,
and ground. When adding devices to the IDE interface, one device is designated as the master device
and another is designated as the slave or subordinate device. These designations are determined by
switches or jumpers on each device. There are two IDE ports, one designated 'Primary' and the other
'Secondary,' allowing for up to four devices to be attached. The total number of physical IDE devices is
dependent on the mechanical package.
For the IDE interface, no resource assignments are given in the system memory or the direct memory
access (DMA) channels. For information on the resource assignments, see “Input/Output Address Map”
on page 61 and Figure 49 on page 65 (for IRQ assignments).
Two connectors are provided on the riser for the IDE interface. For information on the connector pin
assignments, see “IDE Connectors” on page 55.
PCI-to-ISA Bridge
On the system board, the Intel PIIX4E provides the interface between the peripheral component interface
(PCI) and industry standard architecture (ISA) buses. The chip set is used to convert PCI bus cycles to
ISA bus cycles; the chip set also includes all the subsystems of the ISA bus, including two cascaded
interrupt controllers, two DMA controllers with four 8-bit and three 16-bit channels, three counters
equivalent to a programmable interval timer, and power management. The PCI bus operates at 33 MHz.
The ISA bus operates at 8.25 MHz.
For the ISA bus, no resource assignments are given in the system memory or the DMA channels. For
information on resource assignments, see “Input/Output Address Map” on page 61 and Figure 49 on
page 65 (for IRQ assignments).
USB Interface
Universal serial bus (USB) technology is a standard feature of the computer. Using the chip set, the
system board provides the USB interface with two connectors. A USB-enabled device can attach to each
connector, and if that device is a hub, multiple peripherals can attach to the hub and be used by the
system. The USB connectors use Plug and Play technology for installed devices. The speed of the USB
is up to 12 MB/sec with a maximum of 127 peripherals. The USB is compliant with Universal Host
Controller Interface Guide 1.0.
Features provided by USB technology include:
Support for hot pluggable devices
Support for concurrent operation of multiple devices
Suitable for different device bandwidths
Support for up to five meters length from host to hub or from hub to hub
Guaranteed bandwidth and low latencies appropriate for specific devices
Wide range of packet sizes
Limited power to hubs
For information on the connector pin assignments for the USB interface, see “USB Port Connectors” on
page 58.
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Technical Information Manual
