---
title: Motorola WDR-1-Bit Computer
categories:
- Computers
types:
- Home Computer
origins:
- U.S.A.
years:
- '1981'
cpus:
- Motorola MC-14500
params:
  name: WDR-1-Bit Computer
  company: /companies/motorola
  company_name: Motorola
  specs:
  - label: NAME
    value: WDR-1-Bit Computer
  - label: MANUFACTURER
    value: Motorola
  - label: TYPE
    value: Home Computer
  - label: ORIGIN
    value: U.S.A.
  - label: YEAR
    value: '1981'
  - label: END OF PRODUCTION
    value: '1990'
  - label: BUILT IN LANGUAGE
    value: None
  - label: KEYBOARD
    value: 29 keys with instruction and octal keypads, Reset and clock keys
  - label: CPU
    value: Motorola MC-14500
  - label: SPEED
    value: From manual clock pulses to 1 MHz
  - label: RAM
    value: 256 byte to unlimited memory size
  - label: ROM
    value: Unknown
  - label: TEXT MODES
    value: LED display
  - label: SOUND
    value: Sound capabilities
  - label: BUILT IN MEDIA
    value: none
  - label: POWER SUPPLY
    value: 9V battery
  - label: PERIPHERALS
    value: Unknown
  - label: PRICE
    value: '135'
  tabs:
  - photos
  - links
  photos:
  - title: SYSTEM BOARDS
    subtitle: ''
    text: ''
    image: null
  - title: KEYBOARD CLOSE-UP
    subtitle: ''
    text: |-
      Notice the 16 white keys, one for each processor instruction, and the black octal numeric keypad.

      Processor instructions set:\
      **NOP** No Operation\
      **LD** Load result register\
      **LDC** Load complement\
      **AND** Logical AND\
      **ANDC** Logical AND complement\
      **OR** Logical OR\
      **ORC** Logical OR complement\
      **XNOR** Exclusive NOR\
      **STO** Store\
      **STOC** Store complement\
      **IEN** Input enable\
      **OEN** Output enable\
      **JMP** Jump\
      **RTN** Return\
      **SKZ** RR = 0\
      **NOPF** No Operation, set flag
    image: null
  links:
  - title: German page about the WDR computer
    url: http://www.wdr-1-bit-computer.talentraspel.de
    text: Including the full WDR user manual (in German).
  comments:
  - author: Achim Baqué (Germany)
    date: Saturday 29th January 2022
    text: Hi, I do preserve and collect vintage computers. Please contact me (Contact via my website) if you have the WDR computer to offer.
  - author: alysdexia
    date: Wednesday 13rd November 2019
    text: |-
      That''s not nesciently built$ you are.\
      "LCD display": retard
  - author: Dave
    date: Tuesday 10th October 2017
    text: Certainly does have a nice front panel! Easy to understand, I wonder what programming it was like, I''ve never even heard of a 1-bit processor before...
  - author: OC01
    date: Monday 28th October 2013
    text: |-
      http://wdr-1-bit-computer.talentraspel.de/documents/wdr_1-40.pdf

      Here''s the manual. It''s in german, but page 13 has the basic schematics.
  - author: Simon
    date: Thursday 19th September 2013
    text: I think 256B Ram is used as rom-where you load the program.
  - author: Silent-Hunter (Maryland, USA)
    date: Monday 19th August 2013
    text: I want one!
  - author: Bill Gates
    date: Thursday 22nd September 2011
    text: Will it run Windows Vista?
  - author: dionisius (indonesia)
    date: Monday 30th May 2011
    text: yeah it is RISC to the MAX!! Where to find the scheme??
  - author: Pharoah (USA)
    date: Saturday 26th November 2005
    text: |-
      It's RISC to the extreme!\
      (Move over OISC)\
      LOL
  oc_id: 834
  source:
    url: https://web.archive.org/web/20230528105009/http://www.old-computers.com/museum/computer.asp?c=834
    date: '2023-05-28'
---

This is a homemade and nicely built training computer, and probably one of the rare computers in the world based on the 1-bit (yes, one bit) Motorola MC14500 processor.

This machine was conceived en sold in Germany by **DATANorf Hard and Software** in kit or ready-built forms.

Originally, the MC-14500, also called Industrial Control Unit (ICU) was a CMOS processor designed for controlling simple industrial devices and making binary decisions based on successive single bit information. One could find it also in LCD display drivers or as a serial port manager.

It has 16 instructions, including bit transfer, logical single bit comparisons (OR, XOR, AND, NAND), Jump and subroutines. Its internal clock speed started from manual pulses to about 1 MHz.

The pictured computer, made by a German anthusiast, worked when connected to a 9V battery. It includes a LED IO board, CPU board and 512 byte RAM board. The keyboard featured one key for each processor instruction and an octal numeric keypad. Some sounds may be produced through the attached amplifier and loudspeaker.

More information from **Kai Ludwig**:\
The MC-14500 based "WDR-1-Bit-Computer" was invented about 20 years ago as a holiday-project by **Burkhard John** and **Volker Ludwig** for educational purposes.

In those days I was running the german company "DATANorf Hard and Software". It sold the "WDR-1-Bit-Computer" as kit. The ciruitboards were homebrew and there were many additional modules available.\
Later we made an 6 part educational school-TV-serial with WDR Television and the German company Raffel-Electronics got the licence for professional distibution of the kits with industrial manufactured circuitboards.

Your picture shows a version sold by DataNorf to a home enthusiast. The attached board contains a NE555 oscillator to make a sound. The pitch can be adjusted by the potentiometer.

<table> <tr> <td></td> <td>We need more info about this computer ! If you designed, used, or have more info about this system, please send us pictures or anything you might find useful.</td> <td></td> </tr> </table>