Omega_MSX2

Update of the Omega Home Computer Project

Original description

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).

July 18, 2023

Added new ROMs.

Keyboard PCB 1.1

At the moment still unchanged from the original design.

Mainboard PCB 1.2.5 MKV

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

Mainboard PCB 1.2 MKV

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.

Mainboard PCB 1.1 MKV

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)

Notes

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).

merlinkv/Omega_MSX2