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Scribble Pen Plotter: The Electronic Parts
Adding the (Figurative) Spark of Life to Scribble
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Scribble Pen Plotter: The Mechanical Parts
Ending the Beginning of a Very, Very Long Project
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Modular Monitor: Serial Terminals, Hardware Bugs, and You
Connecting the 6502 to a Serial Terminal Turned Out to be Harder Than Expected. When I designed my minimal 6502 development board, I made plenty of concessions to keep the project feasible. A lot of my grandiose ideas for it turned out to be impractical, but I’m still using it. Why not? It’s still a…
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Discrete VGA Graphics Adapter: Text Mode
Special Hardware for Plain old Text. Last time, I got my VGA circuit displaying an actual image. An off-color, artifact laden, not quite in the right place image, but an image nonetheless. Good enough to push the concept further, if nothing else. Text mode is exactly what it sounds like: a special mode for displaying…
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6502 Development: NOPerator Debugging Aid
A Very Simple 6502 Accessory That can Catch Very Complex bugs. Debugging is hard. Anyone who programs computers knows how hard it is to get stuff working reliably. Tiny oversights can lead to massive problems, often in ways that aren’t obvious. Patches get churned out on a daily basis. Hardware engineers have it much, much…
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Discrete VGA Graphics Adapter: Framebuffer and DAC
Putting Actual Graphics Into the Graphics Adapter Last time, I threw together a VGA time base. I didn’t spend much time elaborating on it, because honestly it bores me. There is only so much you can say about a counter that hasn’t already been said. This time around the goal is to display an actual…
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Discrete VGA Graphics Adapter: Time Base
Part 1: VGA Time Base Generation Ever since I started designing computers, I knew I needed to come up with some kind of graphics interface. Preferably one that didn’t require specialty hardware, licensing, or only worked with very old displays. There is one, and only one, interface that does the job: VGA. Despite being completely…
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6502 Minimal Development Board
A Minimalist First Step Into Complex 6502 System Design. I’ve had a serious interest in computer hardware since high school. In between attempts to design my own CPU, I also took some interest in the 6502 shortly after finding Veronica. I promptly ordered two R65C02s- and did nothing with them. Keep in mind this was…