A to D Test

This document provides the technical documentation and assembly source code for the "A to D Test" diagnostic program. Developed by the Diagnostic Group in September 1970, the program is designed to test the functionality, continuity, and calibration of the Analog-to-Digital (A/D) converter hardware on the PDP-12 computer system.

Key aspects of the document include:

• Purpose: To verify A/D converter operation, test preamplifier gain and offset, and confirm channel switching functionality using a VR12 display.
• System Requirements: The test requires a PDP-12 computer, a VR12 display, and a standard Teletype (ASR-33 or equivalent).
• Operating Instructions: It outlines the specific loading and initialization procedures, including setting switches on the PDP-12 console to specific values (e.g., setting the mode switch to L mode, and adjusting the brightness pot).
• Diagnostics: The program includes various test routines for channel sampling and display, with specific switch settings (SSW) to toggle between different sets of input channels and display modes.
• Error Handling: It provides a basic overview of how to troubleshoot issues, directing technicians to the primary PDP-12 maintenance manual if hardware errors persist during the diagnostic.
• Source Code: The remainder of the document consists of the commented assembly source code used to execute these diagnostic routines.