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A project log for Intel 80286 HomeBrew Computer

A HomeBrew Intel 80286 computer with ISA ports

dominic-emond-belangerDominic Emond-Belanger 12/16/2023 at 19:150 Comments

A quick update after a 3 weeks break!

The processor board is fully built and I was able to free run the CPU without being connected to the motherboard. I already found some improvement to be done on the next revision :

Processor board v0.3

The next step was to populate the motherboard and began the work on the CPLD in Quartus.

It was the time for the big test... and it didn't go well..

The first issue was a huge short on the power rail, I found out that my VCC and GND pins on my edge connector where flipped. To be sure I looked back the schematics and confirmed that the A and B sides of the connector where not flipped :

Then I realized that the footprint that I used was wrong... the A and B sides where indeed flipped and where mislabelled!

So now that I know the issue, I need to take a decision if I spin a new revision for my processor card or if I do a workaround for now in case I found more issue before ordering a new board.

I worked on the revision v0.4 of the processor board, I fixed the edge connector, added the pins headers and remove the GAL. I still need to integrate the 82288 bus controller in my chipset later.

Processor board v0.4

Before ordering this new revision, I want to do more test on my current v0.3 revision if possible. I have ordered a PCI extension that I will re-wire to be able to use my v0.3 board and make sure that I do not have other issue with the design.

Next steps

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