DELQA-PLUS Addendum to DELQA User's Guide

This document is an Addendum to the DELQA User's Guide for the DELQA-PLUS board, a new version of Digital's Ethernet/IEEE 802.3 LAN-to-Q-bus board, published in September 1989. Its primary purpose is to provide supplementary instructions for using the DELQA-PLUS board, specifically when operating in its new "DELQA-T mode" (or "Turbo mode"), which offers higher data throughput and a simpler programming interface compared to the traditional "DELQA-normal mode."

The addendum is structured into three main parts:

1. DELQA-PLUS Installation (Chapter 5): This section details the hardware setup for the DELQA-PLUS board in DELQA-T mode. It covers setting on-board switches to configure the board's Q-bus address, select its operating mode, and enable features like the Host Inactivity Timer (HIT). It also provides guidance for configuring multiple DELQA-PLUS boards on the same Q-bus system.

2. DELQA-PLUS Programming (Chapter 6): This extensive section is aimed at device driver developers. It outlines the tasks a driver performs to operate the DELQA-PLUS board in DELQA-T mode. Key programming aspects include:

   • Selecting DELQA-T mode: Instructions on how the driver uses specific registers (XCR0, XCR1) to switch the board from DELQA-normal to DELQA-T mode.
   • Board operation: Steps for orderly start-up, data transmission, data reception, orderly shutdown, software resets, and changing operating parameters.
   • Interaction mechanisms: Explanation of the various data structures (e.g., init block, transmit/receive descriptor rings, buffers) and on-board registers (e.g., ARQR, SRQR, ICR, IBAL, IBAH, SRR) used by the driver to communicate with the board.
   • Interrupt handling: How the board notifies the driver of completed operations and how the driver can block or unblock interrupts for efficiency.
   • Host Inactivity Timer (HIT): Its purpose (returning the board to DELQA-normal mode if the host crashes) and how to enable/set its timeout value.

3. Reading The DELQA-PLUS Board's ROM Version (Appendix D): This appendix provides instructions for host software (the device driver) to verify the board's ROM firmware version. A minimum ROM version (2.0.0) is required for DELQA-T mode operation, and the document describes a process involving software resets and special MOP element blocks to obtain this information.

In essence, the document serves as a crucial technical guide for integrating and programming the advanced features of the DELQA-PLUS board, particularly its high-performance DELQA-T mode, for system developers.