This repository documents my "Colossus Control Computer" which was my main go-to development machine ("It has every feature including the kitchen sink") that was started in March 1985.
I call it a "beast of a Z80 machine" because it has more odds and ends + add-on gadgets than with most self-built computers. It was also the test bed and development platform for my follow-on March 1987 "Phoenix MIDI Computer". An interesting sub-project for Colossus was my Dec 1985 'Drum Pad Triggers for a MIDI Drum Machine'.
- Overview of the Colossus Computer
- The Basic Feature Set
- Source Files
- Block Diagrams
- Schematics
- System Function Overviews
- Images
- Z80A 8-bit processor running at 2 to 4Mhz.
- Z80 CTC general purpose timer
- Z80 SIO (serial I/O). Port A = RS-232, Port B = MIDI
- Z80 PIO (parallel I/O) to interface to the drum trigger pads
- 8253 programmable timer
- 8255 parallel ports A, B and C
- 8279 to interface to the keyboard and the 8 segment LED display
- 58167 real time clock with Dallas DS1210 battery backup controller
- 2764 EPROM memory
- 8K 6264 static memory (used for code execution during CP/M3 DRAM bank swapping)
- 1MB of DRAM + controller
- RCL9's "Universal I/O Port" interface. The pinout can be found at the end of this page.
- Atari 800 cartridge 30-pin interface
- Roland M-16C and M-64C synthesizer patch cartridge interface
- 5-1/4" floppy disk controller and interface
- SASI hard disk controller interface
- 2 line Hitachi H2568 40-position LCD display (interfaces for two of these displays)
- 8 segment LED display
- 8 channel, 8-bit multiplexed analog-to-digital converter based on the TI ADC0809 to measure 8 potentiometers
- 9 drum pad triggers (using piezo-electric microphones)
- MIDI in and out connectors (for a Roland TR-707 drum machine interface)
- Votrax SC-01A speech synthesis + sound mixer and amplifier + supporting software in the monitor ROM
- Numeric keypad
- Scanned ASCII keyboard
- PAL16L8 for I/O port decode (refer to 'decode1.abl')
- Kepco switched mode power supply from Exceltronix Toronto (+5v at 4.65A, +12v at 2.8A, +12v at 2A and -12v at 0.5A).
| Filename | Description |
|---|---|
| sbcmon.mac | The firmware for Colossus |
| lcd.mac | Hitachi LCD driver |
| speak.mac | Votrax SC-01A speech synthesis driver |
| xmodem.mac | Xmodem send/recieve routines |
| simon.mac | The game of Simon for an external hardware device |
| keytbls.mac | Keyboard translation tables |
| dacsynth.mac | A simple music tone generator using two DACs |
Memory map:
| Function | Schematic |
|---|---|
| 1MB dynamic RAM controller - Page 1 |  |
| 1MB dynamic RAM controller - Page 2 |  |
| 5-1/4" disk driver interface |  |
| 8 channel multiplexed ADC interface |  |
| Votrax SC-01 speech synthesizer |  - Oct 25 1985.jpg) |
| 8255 I/O port (aux board) |  - Oct 25 1985.jpg) |
| Atari 800 cartridge interface |  |
| Auxiliary board decode |  |
| CPU - Bus buffering - I/O and memory decode |  |
| Configuration I/O ports |  |
| General I/O ports and LCD interface (aux board) |  - Oct 25 1985.jpg) |
| Hard disk interface |  |
| Inter-board buffers |  |
| Interrupt structure and LED board layout |  |
| Keyboard-LED driver |  |
| Keypad multiplexing |  |
| Memory and I/O decode |  |
| Z80-PIO (parallel I/O) interface |  |
| Real time clock (aux board) |  - Oct 25 1985.jpg) |
| Resident 4K RAM and Banked EPROM |  |
| Roland synth cartridge interface |  |
| Z80-SIO Serial interface |  |
| Timers |  |
| Function | Document |
|---|---|
| Software and hardware interrupts |  |
| 8253 programming |  |
| 8255 bit assignments + Universal I/O Port |  |
| Auxiliary board I/O map |  |
| I/O driver functions |  |
| Keyboard special function numbers |  |
| Main board I/O map |  |
| MIDI driver functions |  |
| RS-232 serial driver functions |  |
| Static RAM vector table |  |
| System driver functions |  |
The main controller board:
And its auxiliary daughter board:
Rear view of the LED display panel and its drivers:
Drum pad triggers for a MIDI drum machine:
The game of Simon which connects to the parallel port:
