MSX Goa'uld board with Tang Nano 20k
MSX2+ engine in Z80 socket. It turns one MSX into an MSX2+ by replacing Z80 processor. FPGA in board contains:
- Z80
- V9958 with hdmi output
- MSX2+ BIOS
- 4MB mapper
- RTC
- PSG through hdmi
- SCC (audio only) through hdmi
Logic acts on bus control signals so that internal devices inside fpga take priority over external devices.
Revision 2 uses SOIC-20 for 74HCT373 and 74LVC245 ICs, which are smaller:
Warning: not yet fully working on all tangs!
Tips:
- Use integrated circuits from trusted sources
- Use turned pins in header to avoid damages in Z80 socket
- Board is sensitive to dirty electrical contacts, way more than Z80. Keep cartridge contacts clean
- Diode avoids hdmi plug from powering the MSX, but causes a voltage drop. If tang doesn't boot, bridge the diode and remember to remove hdmi cable when not using
- When soldering headers, start with the inner one (Z80)