Mini MC14500

The Mini MC14500 SBC is a very simple board built around the Motorola MC14500B ICU (Industrial Control Unit) https://en.wikipedia.org/wiki/Motorola_MC14500B. The impetus for this board was an article on the VASTOR processor that was built at the University of Toronto. The following article explains that processor http://www.dissonance.com/archive/journals/Loucks82.pdf. This board is not a VASTOR processor but a single ICU proof of concept based on reference design from Motorola.

All Data, Instruction and Clock entry is done via switches.

The Mini MC14500 board has the following features

• 8 LED's for state output
• 6 Switches for programming and data input
• Expansion header to allow direct connection to say a parallel port for control by another CPU.
• The silk screen for the board has all of the OP codes for quick reference

Board: mini mc14500 Board Layout

Schematic: mini mc14500 Schematic

KiCAD and Manufacturing Files: mimi mc14500 KiCAD and Manuf

BOM: Mini MC14500 BOM

Test Programs

To run the test programs you need to undertake the following as the precursor

1. Data: 1
2. Control: IEN (1010)
3. Clock
4. Control: OEN (1011)

Logical AND example

1. Data: 1
2. Control: IEN (1010)
3. Clock
4. Control: OEN (1011)
5. Clock
6. LD (0001)
7. Clock
8. AND (0011)
9. Clock
10. STO (1000)
11. Clock

Note the currently manufactured board has a single erata that requires the cutting of one track and soldering of one wire between 2 points. The build files have not been updated.

The build is very simple. Install

1. Resistors and capacitors
2. Transistors and IC sockets
3. LED's
4. Switches
5. Undertake the required modification as per the erata photo

Demonstration Video

Bare board

Erata Photo - Rear cut and wire jump