KMC11 General Purpose Microprocessor User's Manual

This document is a preliminary user's manual (dated May 1977) for the KMC11-A general-purpose microprocessor, manufactured by Digital Equipment Corporation (DEC).

Key aspects of the KMC11-A:

• Purpose: Primarily designed as a UNIBUS-compatible I/O processor and data handler for PDP-11 systems, its main function is to offload the CPU by managing high-speed input/output operations.
• Architecture: It is a microprogrammable device, meaning its specific functions are determined by user-defined microcode stored in a 1K-word writeable control RAM (CRAM). It also contains 1KB of main memory for data storage, distinct from its instruction area.
• Operations: It performs Direct Memory Access (DMA) using Non-Processor Request (NPR) transactions and handles interrupt transactions. It communicates with the PDP-11 CPU via UNIBUS Control and Status Registers (CSRs).
• Enhancements: Compared to the earlier DMC11, the KMC11-A features writeable control storage and an increased main memory. Crucially, it supports multiple consecutive NPRs without relinquishing UNIBUS mastership, improving data transfer efficiency.
• Applications: It is frequently used in conjunction with DMC11 Synchronous Line Units (e.g., DMC11-DA, -FA, -MA, -MD) to control various communication protocols and interfaces (coaxial cable, RS-232-C, V.35) at different speeds.
• Manual Contents: The document covers installation procedures, including physical placement, power requirements, and setting device and vector addresses via switches. It details the UNIBUS and microprocessor's internal control and status registers, microinstruction formats (BRANCH and MOVE), and provides programming examples and notes, emphasizing critical procedures for control transfers and NPR usage to avoid system issues.