Time for an update on my HomeBrew Intel 80286 computer, I recieved my breakout boards this week, so it’s time to start prototyping!

As soon the boards where populated, I began to build a simple prototype version of my computer with some RAM, ROM and I/O port to test some basic code. I used an Arduino Mega to debug the address and data line (based on rehsd design) :

After 3 weeks of debuging I was able to make some basic code that output value to the LED bargraph located on the right of the breadboard. Next step was to interface with something more complex, I had some VFD screens with a 8 bits parallel interface in my parts bin so I decided to gave it a shot.

I was able to output the classic ‘Hello World’ on the VFD screen. (The last letters are not seen due to the camera shutter)

Now that I’m able to write to the I/O port I decided to order more chips for more complex interactions :

  • W65C22 – Western Digital – Versatile Interface Adapter (VIA)
  • KS82C55A – Samsung – Programmable Peripheral Adapter (PPI)

When Ebay shoping for the VIA and PPI chips I stumble on a broken Tandon 80286 motherboard sold only for parts, so I decided to grab it and try to reverse engineer the board to gain some insight on its design.

To be continued …

Dom