DTE20 Ten-Eleven Interface Unit Description

This document is a technical manual, "DTE20 TEN-ELEVEN INTERFACE UNIT DESCRIPTION," published by Digital Equipment Corporation in 1976. It describes the DTE20 Console Processor Interface, a hardware unit designed to connect PDP-11 "front-end" processors to the KL10 Central Processor.

The manual outlines the DTE20's capabilities and operation at three levels: an overview, functional description, and detailed logic description.

Key functions and features of the DTE20 include:

1. Front-End Processor Support: Enables PDP-11s to act as front-end processors for the KL10, handling tasks such as unit record equipment, communications, KL10 diagnostics, and system bootstrapping.
2. Console Functions: Provides "Examine" (read) and "Deposit" (write) operations to KL10 memory, which can be "protected" or "unprotected" based on the PDP-11's privilege level.
3. Interprocessor Communication (Doorbell Function): Allows both the KL10 and PDP-11 to interrupt each other, facilitating coordinated activities and status exchange via dedicated communication regions in KL10 memory.
4. High-Speed Data Transfer: Supports efficient, simultaneous two-way transfer of variable byte (8-bit or 16-bit) data between KL10 and PDP-11 memory using Direct Memory Access (DMA/NPR) and Unibus interrupt features.
5. Diagnostic Capabilities: Offers extensive diagnostic features for both the KL10 Central Processor (via a diagnostic bus) and the DTE20 interface itself, supporting single-step operations and bootstrap procedures.
6. Data Buffering and Control: Utilizes a semiconductor Random Access Memory (RAM) within the interface for buffering data and control words, accessible by the PDP-11. It also includes various addressable and non-addressable registers for control and status.
7. Bus Interfacing: Communicates with the PDP-11 via the Unibus (operating in a master-slave relationship) and with the KL10's EBox via the EBus. It handles parity generation and detection for data transfers.

In essence, the DTE20 serves as a crucial bridge, enabling robust communication, data exchange, and diagnostic control between the PDP-11 and KL10 processors.