80286 Retro computer board with FPGA
- MSDOS 3.3 / 4.0 / 6.22
- Windows 2.0 in CGA mode
- Some old CGA games
- Prince of Persia (CGA and VGA mode)
- Full-speed (12 Mbit/s) device support for fast gaming keyboards and mouses.
- Composite device support (Radio keyboard+mouse, 2-in-1 devices).
- USB PHYs are now controlled by RISC-V I/O processor. Firmware was written in C and can be easily improved.
In this version only upper USB port is connected. The lower one needs some firmware rework. Joystick and mouse report are ignored now and will be available soon.
The RISC-V core will print USB device information on a DEBUG port. If you need the DEBUG port to be controlled by main processor comment "txd" line on a RISC-V UART and uncomment "txd" line of a CPU's UART.
Please use this compact BIOS:
https://github.com/b-dmitry1/BIOS
P-CAD 2006, Sprint Layout 6, and prepared for manufacturing Gerber files could be found in a "pcb" directory.
Technology:
- 4-layer PCB.
- 100x100 mm size.
- 0.2 mm min hole.
- 0.46 mm min via diameter.
- 0.127 mm min track.
It is safe to increase hole size to 0.3 mm, via to 0.63mm, and track width to 0.15 mm.
All the electronic components including FPGA (EP4CE15F23C8N) and CPU (80c286) could be found on AliExpress.
FPGA pin test is included. Check the fpga_pin_test project.
Top view:
Bottom view:
Simplified schematic diagram:
Please use Altera Quartus II 13.0sp1 to compile the project.
Please use disk images from my e86r project:
https://github.com/b-dmitry1/e86r
Just write a FreeDos or an empty image to a SD card, mount it and add your files using File Explorer.
- Electrical schematic diagram is in "sch" directory.
- Please check the "doc" directory.
The project is provided "as is" without any warranty. Use at your own risk.