DHV11 Technical Manual

This document is the Technical Manual for the Digital Equipment Corporation (DEC) DHV11, an asynchronous multiplexer designed for LSI-11/Q-bus systems.

The manual provides comprehensive information for installation, programming, technical understanding, and maintenance of the DHV11.

Key Features and Capabilities of the DHV11:

• Channels: Offers eight full-duplex asynchronous serial data channels.
• Data Transfer: Supports both Direct Memory Access (DMA) and single-character programmed transfers from the host system.
• Buffering: Includes a large 256-entry First-In-First-Out (FIFO) buffer for received characters, dataset status changes, and diagnostic information, reducing host system overhead.
• Compatibility: Compatible with RS-423-A/V.10/X.26 and RS-232-C/V.28 standards, enabling full-duplex point-to-point or auto-answer dial-up operations.
• Speed: Programmable split speed per line, with a maximum channel rate of 38400 bits/second and a total module throughput of 15000 characters per second.
• Bus Interface: Compatible with Q16, Q18, and Q22 Q-bus architectures.
• Flow Control: Features automatic X-ON/X-OFF flow control for both transmitted and received data.
• Diagnostics: Incorporates on-board self-test and background monitor diagnostics, along with programmable test facilities for fault isolation. Functions are programmable, except for hardware-set device and vector addresses.
• Form Factor: Implemented as a single quad-height module (M3104).

Document Structure and Content:

• Introduction: Provides an overview of the DHV11, its general and physical descriptions, specifications (environmental, electrical, performance, data rates, throughput), and interfaces (system bus and serial).
• Installation: Details the unpacking and inspection process, setting device and vector addresses via DIP switches, backplane connections, priority selection for DMA and interrupts, module installation procedures, and usage of various cables and connectors (distribution panel, loopback, null/full modem).
• Programming: Explains the various control and status registers (CSR, RBUF, TXCHAR, LPR, STAT, LNCTRL, TBUFFAD1/2, TBUFFCT), programming features such as initialization, configuration, different transmission and reception methods, interrupt control, X-ON/X-OFF implementation, error indication, and modem control. It also includes programming examples.
• Technical Description: Delves into the internal hardware architecture, including the Q-bus interface, serial interfaces (DUARTs), control section (common RAM, store arbitrator, microcomputers, data flow), other circuits (voltage converter, oscillators), and ROM-based diagnostics.
• Maintenance: Outlines the maintenance strategy, internal diagnostics (self-test, Background Monitor Program), and external diagnostics (XXDP+ and MicroVAX system tests), troubleshooting flowcharts, and a list of Field Replaceable Units (FRUs).
• Appendices: Provide in-depth information on integrated circuit descriptions (8051 Microprocessor, SC2681 DUART, DC003/DC004/DC005/DC010 ICs), detailed modem control, automatic flow control mechanisms, and an installation guide for the DHV11 Remote Distribution Panel Cabinet Kit, along with a glossary of terms.

The manual is intended for first-line service, field service support, and customer engineers, offering a complete guide to understanding, installing, programming, and maintaining the DHV11.