Fr, Fdis and Fadc for Pdp-12 Input/Output

This document provides documentation and PAL-8 assembly source code for three specialized subroutines designed for the PDP-12 computer to be used with PS/8 FOCAL. These routines facilitate specific hardware interactions:

• FADC: Enables sampling of the PDP-12 analog-to-digital converters by specifying a decimal channel number.
• FDIS: Facilitates displaying data on the PDP-12 scope by providing X and Y coordinates.
• FR: Manages sense switches and relay operations (opening and closing relays 0-5 and reading switch status).

The documentation includes instructions for integrating these overlays into FOCAL, the technical error codes generated by the routines, and the full assembly language implementation.