Full picture
Foreword
1.
Overview
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2.
Specifications
3.
Memory Mapping
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4.
Video Modes
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5.
Tilemap Memory
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6.
Tileset Memory
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7.
Sprites Memory
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8.
Font Memory
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9.
Palette Memory
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10.
System Configuration
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11.
Video Configuration
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12.
Text Controller
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13.
SPI Controller
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14.
CRC32 Controller
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15.
Sound Controller
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16.
DMA Controller
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17.
Timer Controller
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Foreword

❤️ Thank you for acquiring the Zeal Video Board!

The Zeal Video Board isn't just a graphics and sound card: it's a chance to dig in, explore, and really get to know how a complete 8-bit video and audio system works, all the way from the inside out.

When I designed it, my goal was the same as for the Zeal 8-bit Computer itself: to create a system simple enough that a single person can understand every detail of its inner workings. You won't find tons of fancy graphic layers, 16 audio channels, or some massive, over-engineered pipeline here. What you get is a stable set of features, just enough to make great games, demos, and software, without getting lost in needless complexity.

I’ve always believed this: the more limited the hardware, the more creative you have to be. The simpler the system, the more you have to think cleverly to make something beautiful or surprising. Many of the most memorable games in history were built under severe hardware constraints, yet they still came up with incredible results just by being creative.

My inspiration came from the Game Boy Color's PPU, a design that is simple enough to master completely, yet powerful enough to create incredible games. Like the GBC, the Zeal Video Board has two graphics layers, sprites, tiles, and a color palette. It also includes four audio channels for music and sound effects.

But graphics and sound alone weren't enough. To make the board a complete companion for the Zeal 8-bit Computer, or any computer, I integrated additional essential hardware: SPI and TF card support, a hardware terminal emulator, CRC computation, DMA transactions, and more! These are features that are hard to implement efficiently without a microcontroller. And that's on purpose — I don't want an MCU doing all the heavy lifting and making the main CPU just watch. If the "helper" is way more powerful than the CPU, it kind of defeats the whole idea.

At the heart of the Zeal Video Board is an FPGA. FPGAs are incredibly versatile, offer a huge amount of logic resources, and are surprisingly affordable compared to large CPLDs. They also let us update the firmware through their onboard NOR SPI flash, no hardware hacking skills required.

The result is a board that is approachable, educational, and fun to master — but also versatile enough to grow with you as your creativity pushes the limits. Whether you're building games, tools, or demos, this is a system you can truly understand from the gates of the FPGA all the way up to the pixels on the screen.

🚀 Let's get started

Disclaimer: All technical details in this documentation apply to firmware v1.0.0 and above. If your board is running an earlier version (e.g., v0.1.0), please update it using the Updating Zeal Video Board guide.