Author Archives: Andrew

ISA Bread Board v1.1

In January of 2022 I developed an 8-bit ISA card that housed breadboard modules for easy prototyping on the ISA bus. Following a request to release the design, I have uploaded all files to Github under open-source hardware license.

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ISA POST Card v5.1

In November of 2019 I taught myself how to use KiCad by practising with the creation of the ISA POST Card v2.0. It was a passable first attempt at using the software, but some annoying bugs were discovered on the … Continue reading

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7 segment display decoder with HEX output v2.0 (Blanking Input)

Some readers may recall an older article that I wrote showing how to emulate a 7 segment display decoder with HEX output functionality, using an ATF16V8B PLD chip. The PLD programming was designed in such a way to mimic the … Continue reading

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7 segment display decoder with HEX output

In seeking to improve my ISA POST card design, I became frustrated at the general lack of modern seven segment display decoders that could decode and display a hexadecimal output. Rather than buy an older second-hand decoder IC, I fell … Continue reading

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New Github

I’ve had a recent reader comment asking for me to share the details of the Keystone 9202 bracket that I’ve used in my ISA POST card design. This has prompted me to create a proper place on my Github account … Continue reading

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Retro-CGA #6 – Character Font

The last post in this series covered the receipt of the Retro-CGA prototype circuit boards, and the soldering of all components onto one of the boards, making a completed prototype card: This post covers the last step in preparing the … Continue reading

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Retro-CGA #5 – Fabrication and Assembly

The last post in this series showed some of the detail of the Retro-CGA as it has come together so far, and ended with the preparation of Gerber files in preparation of having some prototype boards fabricated. After a week … Continue reading

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Retro-CGA #4 – Design Features and Fabrication

The last post on the Retro-CGA showed the gradual progression from schematic design to  board build-up, summarising a period of several busy weeks. This post acts as a summary of that whole exercise, showing some of the board design detail. … Continue reading

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Retro-CGA #3 – Initial Board Design

The last post in this series covered aspects of the initial schematic design of the Retro-CGA. This post will crack on with the initial board design, using the magic of pictures to show the detail of the board build-up. I … Continue reading

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Retro-CGA #2 – Initial Schematic Design

In one of my last posts I pondered the journey required to create an open-source video card inspired by the CGA card that I had repaired, in an attempt to preserve its historically-significant legacy. In this post I will share … Continue reading

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