This project is implementation of an MSX2 compatible computer. The project is built using a combination of 1980’s era components – Z80 CPU, V9958 VDP, AY-3-8910/YM2149F PSG, 8255 PPI, 7400-series logic, and some newer components, such as 512 KiB SRAM and 512 KiB Flash ROM and a few simple programmable logic devices (ATF16V8B SPLDs).

By Sergey Kiselev open source project on Github

Introduction

The main board implements standard MSX2* functionality, as described in the Specifications section below. The main board is designed to be stacked under the keyboard PCB, thus creating a “keyboard computer” form factor typical for 1980’s home computers.

Specifications

• Processor: Zilog Z80 CPU (CMOS version – Z84C00) running at 3.58 MHz
• Memory:
  • RAM: 512 KiB SRAM, expandable to 4 MiB using an optional daugherboard. MSX* compatible memory pager. The RAM is mapped to slot 3-2
  • ROM: 256 KiB or 512 KiB Flash ROM. The ROM is mapped to the slot 0 and sub slots 3-0, 3-1, and 3-3
• Video: Yamaha V9958 or Yamaha V9938 VDP
  • 128 KiB Video RAM
  • Composite, S-Video, and RGB video outputs
• Audio: Yamaha YM2149 or General Instrument AY-3-8910 PSG
• Two MSX* compatible cartridge slots
• Keyboard, joysticks, printer and cassette recorder interfaces
• RTC: Ricoh RP5C01
• Microprocessor Supervisor:
  • Reset generation
  • RTC battery backup
• BIOS: C-BIOS. Compatible with BIOSes from the original MSX2* computers with a similar slot organization and hardware specifications, for example Sanyo* PHC-23J

Omega Keyboard

Omega Enclosure

Acrylic Enclosure for the Omega Home Computer