This video contains a narration followed by a demo, complete with clicking.
(2:00 minutes runtime)
Video Tutorial
For a video presentation describing the machine in depth, click here (to intro page).Features of the Arithmetic Logic Unit:
Two 8-bit inputs (from B and C registers)
8-bit result (onto data bus)
3-bit function code input
Functions: Add, Increment, And, Or, Xor, Not, Shift-left, Nop
Carry output (from Add, Increment)
Zero-detect output
Features of the Register Unit:
8 Registers (8-bits each)
Register Names: A, B, C, D, M1, M2, X, and Y
Data Bus (8 LEDs and 8 Switches)
Features of the Program Control Unit:
Program Counter (16 bits)
Instruction Register (8 bits)
Jump Target Register (16 bits)
Increment Unit (16 bits)
Increment Register (16 bits)
Address Bus (16 LEDs and 16 Switches)
Features of the Sequencer Unit:
Clock (Using capacitors for delay)
Finite State Control (24 states)
Instruction Decoding
Main Memory (32K x 8bits, static RAM chip)
General Features:
Data Bus (8 bits)
Address Bus (16-bits)
All relays are the identical part (Four-Pole-Double-Throw, 12 Volts)
415 Relays
111 Switches
350 LEDs
Max Power Consumption: Estimated 12 Amps @ 13.5 Volts (160 Watts)
More Info
For more information, click here (Last updated, 17 November 2009: Circuit diagrams added)
Video Tutorial
For an in-depth video presentation describing the design of machine,
click here (to intro page).
About the Author
Harry H. Porter III, Ph.D.
Computer Science Department
Portland State University
Back to Harry's homepage:
click here
Short Bio of Harry:
click here
Back to Relay Computer, main page:
www.cs.pdx.edu/~harry/Relay
Send email to Harry: harry@cs.pdx.edu