AlphaPC 164LX Motherboard Technical Reference Manual

This document is the Compaq AlphaPC 164LX Motherboard Technical Reference Manual, a revised edition (EC–R46WC–TE) that supersedes a previous version.

It serves as a comprehensive guide for system designers and evaluators interested in building or assessing computing systems based on the Alpha 21164 microprocessor and the 21174 core logic chip.

The manual provides detailed information on:

• System Components and Features: An overview of the motherboard's architecture, including the 21174 core logic chip, memory subsystem (SDRAM, L3 Bcache), PCI and ISA interfaces, and miscellaneous logic.
• System Configuration and Connectors: Instructions on setting hardware configuration jumpers (e.g., CPU speed, Bcache size, boot options, flash ROM update, password bypass) and detailed pinouts for all onboard connectors (PCI, ISA, DIMM, IDE, diskette, parallel, serial, keyboard/mouse, power, LEDs, buttons, fans).
• Power and Environmental Requirements: Specifications for power supply, board dimensions (ATX hole and I/O shield), and environmental operating conditions.
• Functional Description: In-depth explanation of the operational aspects, covering the L3 Bcache interface, 21174 core logic chip functions (main memory, PCI devices, Saturn-IO chip), ISA bus devices (combination controller, flash ROM), interrupt logic, system clocks, reset/initialization, and serial ROM.
• Upgrading: Procedures for increasing SDRAM memory capacity and upgrading the microprocessor speed.
• System Address Space: A detailed appendix describing the mapping of 40-bit physical addresses to memory and I/O space, along with PCI and DMA addressing schemes (dense, sparse, and scatter-gather translation).
• Support: Information on customer support, available supporting products (memory, thermal solutions, power supplies, enclosures), Alpha products, and related documentation.

While comprehensive on the motherboard's specifics, the manual refers to external vendor and IEEE specifications for detailed bus specifications (like PCI or ISA).