Rainbow 100 PC100 System Module Specification

This document details the architecture, functionality, and technical specifications of the Rainbow 100 PC100 System Module. The module features a dual-processor design, incorporating an 8088 CPU (4.815 MHz) and a Z80A CPU (4.012 MHz), which operate simultaneously and share a 62KB block of RAM. Each processor also has its own dedicated memory and peripheral circuitry.

The 8088 CPU is responsible for managing video output, keyboard I/O, a printer port, communications, and other optional features. Its memory includes 24KB ROM for diagnostics, bootstrap, and VT102 emulation, 4KB each of screen and attribute memory for display control, and non-volatile memory (NVM). The Z80A CPU is solely dedicated to controlling the floppy disk interface, utilizing shared RAM and its own 2KB private RAM.

The video subsystem offers VT100-compatible features such as 24-line by 83 or 137-column displays, smooth scrolling, double height/width lines, reverse video, bold, blinking, and underline attributes, controlled by DC011/DC012 video processors. The document also describes the 8088 and Z80A memory maps, I/O maps, interrupt structures, and diagnostic registers for system testing and configuration.

Peripheral interfaces include a software-programmable printer port (RS423 compatible) and a communications port with full modem support, supporting ASYNC/BISYNC modes and RS423 (V.24/V.28) physical interface with independent software-selectable transmit/receive bit rates. The document concludes with information on connector pinouts, power requirements, physical dimensions, reliability goals (12,000 hour MTBF), environmental specifications, and applicable industry standards.