EDDA 3 - Introduction

Parent Category: Articles Category: EDDA 3 - An Early Transistorized Process Computer Written by Administrator

The name EDDA means "Elektronische Digitale Datenverarbeitungs-Anlage" (electronic digital data processor).

EDDA is a process computer from 1969, used for control of production plants. Function and architecture have similarities to early microcontrollers (e.g. PIC1640 from 1976), the design, however, is not "single-chip" but - typical for that period - “wall unit”.

Uncommon are the decimal representation of addresses and data as well as the internal number-serial data processing - today this is particularly known by the ENIAC. Also tricky is a shift register based on core memory, being implemented with minimal effort by using double wire wrap of cores.

schrank geschlossen offen

The EDDA 3 had a flexible architeture and could be expanded with memory and multiple I/O components.

system schema

(Typical components where: "Tastatur" = key board, "Waage" = scale, "Schreibmaschine" = type writer, "Elektromotor" = electric motor, "Programerweiterung " = expansion program memory, "Zusatz-Kernspeicher" = expansion core memory, "Ziffernanzeige" = digit display, "Zähler" = counter.
"Zusätzliche Zwischenelektronik" means "Additional interface circuits")



The concept dates from 1965; predecessors were EDDA and EDDA 2. Circuit elements are discrete transistors and core memories. The design is modular and extendible; modules are electrical cabinets, slide-in units, and circuit boards. The central operating clock is 50 kHz.

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Here is an overview of module use:


(Translation: "Program-Matrix" = program memory, "Entschlüsselung der Adressen und Befehle" = decoding of addresses and instructions, "Erzeugung der Grundtakte" = clock generation, "Rechenwerk mit Überwachung" = arithmetic unit with monitoring, "Netzanschluss" = power line connector, "Kernspeicher" = core memory, "Stecker zum Anschluß von Zusatzeinheiten" = connector for expansion units, "Eingabekanäle" = input channels, "Ausgabekanäle" = output channels  "Stecker zum Anschluss eines Prüfgerätes" = connector for test unit.)

Einschuebe schema