DRV11-WA General Purpose DMA Interface User's Guide

This User's Guide describes the DRV11-WA General Purpose DMA Interface, a module designed for transferring 16-bit data words directly between a Q-bus memory and a user's I/O device. It supports various data transfer modes, including Direct Memory Access (DMA) in Data Transfer Out (DATO) or Data Transfer In (DATI) directions, burst modes (four-word or continuous), byte addressing, and read-modify-write operations. The interface is compatible with both standard and extended Q-buses.

It utilizes six primary registers—Word Count Register (WCR), Bus Address Register (BAR), Extended Bus Address Register (BAE), Control/Status Register (CSR), and Input/Output Data Buffer Registers (DBRS)—which are configured programmatically to initiate DMA transfers.

The document details the physical and electrical specifications of the dual-height, single-width module, including its data transfer rates (up to 250,000 words/sec in single cycle and 400,000 words/sec in burst mode). Key installation procedures are covered, such as setting device and interrupt vector addresses via switches and jumpers, configuring burst and interprocessor link modes, and initial turn-on steps, along with diagnostic programs for LSI-11 and MicroVAX systems.

It also explains the basic operation, including the functions of the various registers and interface lines, different DMA data flow scenarios, timing diagrams, and programming considerations for interacting with the DRV11-WA, including handling interrupts. Finally, the guide describes the DRV11-WA's capability to function as a half-duplex interprocessor link between two computer systems, detailing its operating modes (word, single cycle, burst) in this configuration.