PDP-8 Processor Core and System

Description

The PDP-8 was one of the earliest minicomputers and was in use from the mid 1960s into the 1980s.

Because the PDP-8 was relatively inexpensive and was available in various forms for many years, the PDP-8 is remembered fondly by many programmers and engineers

This project implements a complete PDP-8 system. The system includes the many of the basic PDP-8 peripherals including:

• Configurable PDP-8 CPU
• MS8C 32K-word memory
• KC8E Front Panel
• KE8 Extended Arithmetic Element
• KM8E Extended Memory
• KM8E Time Sharing
• DK8EA/DK8EC/DK8EP Real Time Clock
• KL8E Asynchronous Serial Interface (x2)
• LS8E Printer Interface
• PR8E Paper Tape Reader
• KL8E Disk Controller with 4 RK05 Disks Attached

Status

The system passes all relevant diagnostics (MAINDECs) with the exception of the RK8E Disk Controller. The system boots OS/8 and runs all applications.

Successful Implementations

NEXYS2

The design has been implemented and tested on a Digilent NEXYS2 Evaluation Board using the Xilinx ISE Webpack Version 13.3 toolset.

Note: The 1200K Gate version of the NEXYS2 board is required because all 32K words of RAM are implemented in FPGA block RAM.

Altera DE2-115

The design has been implemented and tested on a Altera DE2-115 Evaluation Board using the Quartus II 11.1 Build 173 Full Version toolset.

ORSoC ordb2a-ep4ce22

The design has been implemented and tested on a ORSoC ordb2a-ep4ce22 Board using the Quartus II 11.1 Build 173 Full Version toolset.

Altera DE0-Nano

The design is currently being implemented on a Altera DE0-Nano Development and Education board using the Quartus II 12.0 Web Edition tool set.

The DE0-Nano is expected to be the least expensive platform for this device and is available at a cost of $86.25 from (among other places) Digikey.