superstar68k

Circa 1984 I designed a 68000 based computer with graphics and sound to be utilized as an arcade type gaming board. The board utilized an Hitach HM63484 GPU as a graphics processor and an SAA1099 for sounds.

It Also had a secondary 8051 compatible CPU made by Dallas Semiconductor the DS-5000 that had built in memory backup and other features. This was used as an I/O and game controller and exchanged information with the 68000 processor which mainly worked the graphics and animation functions. It could communicate serially with a computer/terminal serial port or it could also do rs-485 multidrop so it could be connected to multiple betting stations etc..

It has a ROM debuger and Tiny Basic which was modified to support the GPU internal draw commands. We used this a lot to experiment and to exercise the hardware.

SUPERSTAR COMPUTER SPECIFICATIONS

1. Main Microprocessor : 68000-8 Cpu
2. Program ROM Size : 256K WORDS (512K Bytes)
3. Program RAM Size : 8K Words (16K RAM)
4. CRT Display : 640 Dots X 200 Rasters X 256 Color per dot (Pixel)
5. CRT Controller : HD63484 ACRTC
6. Total Graphics Memory : 512K (One Screen = 128,000 bytes)

HD63484 ACRTC Configuration

1. Dot Clock : 14.318 MHZ
2. 2Clk : 7.159 MHZ
3. ACRTC Type : 8 MHZ
4. Shift Quantity : 8 Pixels Per Memory Access
5. Access Mode : Interleaved access mode
6. Graphic bit mode : 8 Bits Per Pixel
7. Address Increment mode : +4
8. Graphics Memory Type : HD50464 or Equiv. 64K x 4 bits 120ns QTY=16
9. Total Graphics Memory : 512K (One Screen = 128,000 bytes)
10. Vertical & Horizontal smooth scrolling supported.

68000 Memory Map

1. 00000- 7FFFF 256K WORDS OF ROM
2. 80000- 83FFF 8K WORDS OF RAM
3. AX000- AX002 63484 VIDEO IC #1 PORTS
4. AX400- AX7FF VIDEO DAC #1 RAM LOCATIONS
5. CX000- CX002 63484 VIDEO IC #2 PORTS (NOT IMPLIMENTED)
6. CX400- CX7FF VIDEO DAC #2 RAM LOCATIONS
7. EX000- EX002 63484 VIDEO IC #3 PORTS (NOT IMPLIMENTED)
8. EX400- EX7FF VIDEO DAC #3 RAM LOCATIONS
9. 10XX00-10XX02 SOUND IC I/O PORT
10. 10XX04-10XX06 SPECIAL CPU READ PORT (8051 interface)
11. 10XX08-10XX0A SPECIAL CPU WRITE PORT (8051 interface)
12. 10XX0C-10XX0E SPECIAL CPU READ PORT CLEAR (8051 interface)
13. 10XX10-10XX12 NOT IMPLIMENTED
14. 10XX14-10XX16 NOT IMPLIMENTED
15. 10XX18-10XX1A NOT IMPLIMENTED
16. 10XX1C-10XX1E WATCHDOG TIMER CLEAR

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Posting to Github so others may see the design and possible work on a new board with a few less features not needed for the arcade market but to possibly build a small retro computer with cool graphics and sound for educational purposes.