Technical Information 1-19
MDP/MPP Mode
The MPEG data port (MDP) and multimedia peripheral port (MPP) modes are mutually
exclusive of each other. The support for a particular mode is determined by the revision of
the ATI controller in use. MPP provides a direct connect to the ATI MPEG decoder and
has some advantages over MDP. It adds an additional multiplexed address/data bus, which
can be used to connect a range of third party devices like MPEG2 decoders or audio
processors. This bus uses ISA type control and either an 8-bit or 16-bit protocol. The fully
programmable control signals allow it to interface to a variety of devices with minimal
external logic.
ISA Bus
The system board uses the ISA bus for transferring data between the processor and I/O
peripherals and expansion boards. The ISA bus supports 16-bit data transfers and typically
operates at 8 MHz. ISA expansion slot connector pin assignments are provided in
Appendix A.
PCI Local Bus
The 32-bit PCI bus is the primary I/O bus for the system. The PCI bus is a highly-integrated
I/O interface that offers the highest performance local bus available for the Pentium
processor. The bus supports burst modes that send large chunks of data across the bus,
allowing fast displays of high-resolution images.
The PCI bus operates at half the Pentium’s processor speed, and supports memory transfer
rates of up to 105 MB per second for reads and up to 120 MB per second for writes,
depending on processor configuration.
The high-bandwidth PCI bus eliminates the data bottleneck found in traditional systems,
maintains maximum performance at high clock speeds, and provides a clear upgrade path to
future technologies.
The PCI bus contains two embedded PCI devices, the PCI local bus IDE interface, and the
PCI video/graphics controller.
PCI expansion slot connector pin assignments are provided in Appendix A.
PCI Auto Configuration
The system comes with a PCI auto configuration utility that operates in conjunction with
the system’s Setup utility. The utilities automatically configure interrupts, DMA channels,
I/O space, and other parameters to allow addition of PCI boards with minimal user
intervention. (See Section 2 for setup information.)
