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80286 System Roadmap (updated June 2023)

Updated: Jun 12, 2023

Back in January of this year, I posted a list of potential roadmap items for my 26 build. See 80286 System Roadmap ( As I reflect on the list I posted at the time, I feel like I have made good progress.

Major Accomplishments

  • ISA video card supporting 640x480, 16 bits per pixel color.

  • BIOS support of critical interrupts to run FreeDOS.

  • Mouse support.

  • ISA sound card.

  • ISA IDE interface card with CF Card.

  • FreeDOS loaded from CF Card and running.

  • DMA support (hardware at least). BIOS support and testing still needed.

  • Onboard flash BIOS programming.

Next Steps

  • System timer using VIA. complete

  • Continue to implement BIOS interrupts (e.g., IDE disk writing).

  • Update the ISA IDE interface card PCB. The current version has many bodge wires to address design changes post-PCB-design.

  • Bug fixing and performance improvements to better support FreeDOS.

  • Run a couple of basic DOS games (snake, Tetris, etc.).

  • Try out a custom C/C++ DOS application or two.

  • Sound card working in FreeDOS.

  • Ethernet network access with basic TCP/IP support. I will likely offload much of this to an Arduino (Mega or Due?) and communicate from the 286 to the Arduino with SPI.

  • RAM card, using address space above the 1 MB address. Maybe I can support 4 MB of extended RAM.

  • Updated ISA VGA card. Add support for accessing VRAM from both the current 0xA0000 64K window and full memory mapping from an address space above 1 MB? Hardware scrolling? Onboard video co-processor?

  • Possibly, start a 386 DX build, leveraging the current system board design as a starting point.

  • ... ?

I'd love to hear other ideas. Drop me a note.

More to come...

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