Sunday, April 8, 2012

MC Minimal Computer

Restored MC Computer
Fully restored, Humanoido's MC Minimal Computer project is fully functional. What happened to the original disappearing MC?

Not entirely without heart, the Propeller Powered Big Brain has returned the original Propeller chip, taken from the MC Computer project over a half year ago. Enter a new age of Big Brain - the ERA of Exploration, and the MC is now a child. What will it lead to? We may have some ideas...

First the Big Brain was in Assimilation Era and took out the MC Computer, assimilating it completely right down to the Propeller chip. If that wasn't enough, a hard drive crash from a "program and file eating virus" took out PC software, schematics and text files. Working over a half year to restore some files, a small amount of success was achieved, in particular, some of the original MC files were resurrected from the ashes.

Expand with a reset switch & EEPROM
The MC Computer is designed for RETRO Minimal Computing and schools - an entire science is built around one Propeller chip designed to fully function as an experimental and educational computer, ideal for learning binary and programming. The base model is of binary flavor with front panel binary display LED lights and bit toggle switches for setting an 8-bit Byte. A push button is for stepping through programs and entering commands and an extra toggle switch is for add subtract function. The front panel has power on off and banana jacks for hooking up a 3 volts DC power supply. Internally the one chip MC can run on batteries for a very long time. Expansion is rather easy by following the Propeller Demo Board schematic from Parallax. The back is open for easy access to such amenities as adding a crystal, TV, VGA Monitor, keyboard, mouse, EEPROM, speaker, and batteries. But if you do all that, will it still be minimal and low power? The MC will even work on Virtual modules such as TV and keyboard by using software available from the Parallax Forum.

Schematics to build the MC Computer
The first MC
Add a Piezo speaker
Constructing the MC Computer is very basic and easy to accomplish by following the photos and schematic. The schematic shows one Propeller chip, a few lights and switches and power connections. Building it is a cinch.

There's 25 programs that run on the MC Computer programmed in SPIN language and as noted, which may follow under the MIT Licensing for building your own MC. Software demonstrates examples of programming the front panel LEDs and switches, and various features. See the list below.

The MC is a good programming language machine. The upgraded version can run multiple languages like SPIN, PASM, Prop BASIC, FemtoBASIC, and others.

Check this ULTIMATE LIST BIG BRAIN PROGRAMMING LANGUAGES for almost 200 potential languages.

MC01.spin  set entire LED pin group output, slow blink, Pushbutton increases blink frequency to several times a second
MC02.spin  Slow blink all LEDs continuously, toggle in SUB, fast blink all LEDs continuously toggle switch in ADD
MC04.spin  Slow blink all LEDs continuously or fast blink all LEDs continuously when toggle B7 is on (up)
MC05.spin  slow blink all LEDs, fast blink all LEDs if B0 toggle is on (up)
MC06.spin  Blinks LED B4 nine times and stops
MC07.spin  slow blink LED B0 on port pin 0 and repeat 10 times
MC08.spin  Blink third LED B2 on pin 2 continuously
MC09.spin  Blink LED B4 nine times and stop
MC10.spin  LED pattern shift left right, variable speed controlled by pushbutton
MC11.spin  Led mirrors toggle switch state, example - B0 switch lights LED
MC12.spin  Blinks LED B4 constantly
MC13.spin  The LED on pin 3 will blink every second, five times.
MC14.spin  All LEDs are turned on
MC15.spin  Incrementally lights LEDs in a pattern
MC16.spin  Increment Until Condition
MC17.spin  LED B4 is on continuously
MC18.spin  Leds alternate on/off 50% of the time.
MC19.spin  Leds alternate on/off 50% of the time with the ! operator.
MC20.spin  All LEDS on for 1/4 s and off for 3/4 s continuously
MC21.spin  All LEDS on for 1/4 s and off for 3/4 s with post set/clear
MC22.spin  All LEDs flicker until pushbutton then flash
MC23.spin  Demonstrate right shift operator & if, LEDs flash right/left, repeat
MC24.spin  Square Wave, LEDs B5, B6, B7 flicker different rates/illumination
MC25.spin  When the pushbutton is pressed, it will light LED B6 on pin 6

MC Computer Links & Sources
MC Computer Restoration

MC Minimal Computer Reborn

MC Photo Gallery

Propeller Elf II