Digital PDFs

Order Number: EK-KA820-TM

This document is the KA820/KA825 Processor Technical Manual (EK-KA820-TM-003), published by Digital Equipment Corporation in April 1987. It serves as a comprehensive guide for the KA820 and KA825 single-board VAX processor modules, primarily used in VAX 8250 and 8350 computer systems. The KA825 is an enhanced version of the KA820, offering higher performance.

Intended Audience: The manual is written for:

Field personnel responsible for installing and replacing KA825 modules.
Engineers and system programmers who integrate KA825 modules into their own products or systems.

Key Content Areas:

Module Architecture and Components: Chapters 1 and 2 provide an introduction and detailed description of the KA820 module's functional sections, including the CPU (comprising I/E, M, and F chips), the VAXBI bus interface (BIIC), and the port controller with its associated PCI bus devices (EEPROM, boot RAM, watch chip, and RCX50 diskette controller, along with serial-line units). It explains memory management functions, such as the Backup Translation Buffer (BTB) and data cache.
System Power-Up and Initialization: Chapter 3 covers the various power-up sequences, including self-tests (slow and fast), processor initialization, and system initialization. It details how to customize processor behavior using EEPROM settings and control panel signals for restart or console entry.
Console Functions: Chapter 4 describes the console's operation, states, and a range of commands for system maintenance, debugging, and bootstrapping. This includes commands for examining/depositing data, testing hardware, and handling logical console operations in multiprocessor systems.
Exception and Interrupt Handling: Chapter 5 provides crucial information for software development, focusing on how the KA820 handles exceptions (traps, faults, aborts, machine checks) and interrupts. It explains the System Control Block (SCB) and interrupt priority levels.
Dedicated I/O and Memory Devices: Chapter 6 offers programming details for controlling the on-board serial-line units, EEPROM, boot RAM, battery-backed watch chip, and the RCX50 diskette controller.
Diagnostics: Chapter 7 gives an overview of diagnostic software programs (e.g., EVKAA, EVKAB, EBKAX, EBDAN) designed to test the KA820's functionality and assist in troubleshooting hardware failures.

Appendices (A-K): These sections provide essential reference material, including I/O pin definitions, module installation procedures, electrical characteristics of off-board signals, detailed descriptions of BIIC and Port Controller registers, internal processor registers, EEPROM contents, and software boot control flags.

The manual aims to enable users to effectively install, maintain, customize, and develop system software for the KA820/KA825 processor modules within VAX-based systems.