BDV11 Bus Terminator, Bootstrap, and Diagnostic ROM Technical Manual

This document is the "BDV11 bus terminator, bootstrap, and diagnostic ROM technical manual," published by Digital Equipment Corporation in March 1978, for use with the PDP 11/03-L and other LSI-11 bus systems.

The BDV11 is a quad-height printed circuit board (M8012 module) that serves multiple functions on an LSI-11 bus:

• Bus Termination: Provides 120-ohm terminations for LSI-11 bus signal lines.
• ROM Hosting: Includes fixed 4K words of diagnostic and bootstrap ROM, plus user-available space for 2K words of erasable, programmable ROM (EPROM) and 16K words of ROM/EPROM. All ROM is mapped into a 256-word segment of the LSI-11 I/O address space (173000–173776) via a Page Control Register (PCR), which allows various "pages" (128-word blocks) of ROM to be accessed. Jumper settings on the module determine the specific ROM socket assignments and influence boot sequences.
• Diagnostic Aids: Features switches (HALT/ENABLE, RESTART, and diagnostic/bootstrap program selection) and a diagnostic light display (LEDs) to monitor system status and indicate failures.

The manual provides comprehensive details on:

• Installation: Steps for inserting the module into an LSI-11 quad backplane, including pre-installation switch settings and bus pin-outs.
• Operation: Functions of all switches and indicators, and descriptions of the six hardware registers (Page Control, Read/Write, Switch, Display, and BEVNT) used for system control and maintenance.
• Technical Description: In-depth explanations of the BDV11's internal logic, including its bus transceivers, control logic, ROM address and socket selection mechanisms, power-up logic, BEVNT (line-time clock) logic, and display logic.
• Specifications: Physical, electrical, and environmental specifications for the BDV11 module, along with recommended ROM specifications.

The document is intended for technical users familiar with the LSI-11 microcomputer, detailing the module's design, functionality, and interaction within an LSI-11 bus system.