Update of the Omega Home Computer Project
This project is an open source 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).
- 14-04-2024
- Version updated to 1.2 MKV
- Schematics, PCB and Gerbers successfully ported to KiCad 8.0.1
- The board has been rerouted.
- Some components are now SMD
- 12-05-2024
- Added positility to select the connection type of Slots pin 44 (by SPDT switch SW3). They can be connected to GND (normal) or to NMI.
- 20-04-2024
- Version updated to 1.2.7 MKV
- Power lines design has been changed.
- Board has been re-routed.
- 14-04-2024
- Version updated to 1.2.6 MKV
- Schematics, PCB and Gerbers successfully ported to KiCad 8.0.1
- The board has been re-routed.
Added new ROMs.
- Improved routing parameters resulting on a bit more clear video & audio. In my opinion, before the RGB image was very good, now is really great.
- Power Switch footprint modified to, if desired, allow solder big section wires.
- Added another +5v Extra Power connector. The idea is to use it with horizontal pins and connect one small 4x4cm fan on top of the V9958.
- Board is tested working 100% with F4-FMPAC & o4Mega (4MB RAM) modules, internal Gotek with LCD 16x2 screen, cartridges Carnivore 2 & TDC-600 (floppy controller) at the same time with one 5.2v/3A PSU
- Added possibility to use up to four different ROMs (two PLCC32 IC's).
- Added extra footprints for ROM selection switches.
- Changed internal FDD power connector to a better position.
- Changed all routing parameters and a couple of silk errors corrected.
Omega Mainboard PCB 1.1 MKV is a variant of the Mainboards 1.4US & 1.4EU by Sergey Kiselev & Jordi Solis
All "standard" capacitors, resistors & inductors are now in SMD 1206 format and placed at the bottom of the PCB.
New footprints for internal/external connections:
- 5-pins connector for DC-DC converter (+5v IN - +12v/-12v OUT)
- 2-pins connector for Power ON-OFF switch
- Two Extra Power connectors +5v (2-pins)
- One Extra Power connector +12v/-12v (3-pins)
- Connector for FM-PAC Module (AMP-GND, 2-pins)
- Connector for FM-PAC Power (+12v/-12v, 3-pins)
- Connector for RGB & Composite video (5-pins)
- Connector for S-Video (3-pins)
- Connector for Audio (Mono, 2-pins)
- Separate connectors for NMI & RESET (2-pins each)
- NMI signal connected to pin 44 of each slots (MSX3 Update?)
- FDD Power Connector (+5v/+12v, 4-pins)
- Electrolytic capacitors: I recommend to use High Frequency and Low ESR ones.
- SMD resistors: Best is to use ones with 1% tolerance. All must be 1/4w.
- SMD capacitors: I recommend to use X7R type (10%) or less tolerance.
- ROM: AM29F040, SST39SF040 or compatible IC's can be used.
- SPLD's: ATF16V8B or GAL16V8B can be used without needed to use new jed's.
- For power cable and power switch best is to use wires with big section.
- At the moment I recommend to use one 5.2v/3A PSU.
- It's possible to use one 5.5v/3A PSU (near the limits but it's inside the power range).