User`s guide

3.8 PCI Devices
The AlphaPC64 uses the PCI bus as the main I/O bus for the majority of
peripheral functions. The board implements the ISA bus as an expansion bus
for system support functions and peripheral devices.
3.8.1 Intel Saturn IO Chip
The SIO chip provides the bridge between the PCI bus and the Industry
Standard Architecture (ISA) bus. The SIO chip incorporates the logic for the
following:
• A PCI interface (master and slave)
• An ISA interface (master and slave)
• Enhanced 7-channel DMA controller that supports fast DMA transfers and
scatter gather, and data buffers to isolate the PCI bus from the ISA bus
• PCI and ISA arbitration
• A 14-level interrupt controller
• A 16-bit BIOS timer
• Three programmable timer counters
• Nonmaskable interrupt (NMI) control logic
• Decoding and control for utility bus peripheral devices
• Speaker driver
Refer to the Intel 82420/82430 PCIset ISA and EISA Bridges document for
additional information.
3.8.2 PCI Expansion Slots
Four PCI bus expansion slots are available on the AlphaPC64, with one slot
shared with the ISA. The four slots use the standard 5-V PCI connector and
pinout for 32-bit implementation. This allows the system designer to add
additional PCI options.
3.8.3 PCI Graphics Interface
The DECchip 21030 8-bpp Evaluation Board (EB30-8) can be used as a
high-performance graphics processor. This optional add-on occupies one PCI
slot.
The microprocessor memory controller has the capability of performing simple
graphics-oriented data manipulations.
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