Over the course of the project, I have rather thoroughly documented everything from the hardware to the software on my website, http://www.thingsmadesimple.com. So rather than try to re-document that information here, I am going to provide a series of links to each of the articles and videos. The source code for everything can be found on my GitHub as well as the kicad files for the business card PCB (see the article 9 folder).

Article: YM3812 Part 9: SynthCard

Turn that breadboard into a business card sized PCB!

And for reference, here are all of the other videos in the series that describe in detail how the YM3812 SynthCard works:

Article: YM3812 Part 1: Register Basics

Focuses on FM Synthesis basics, the YM3812's register map and electrically controlling the chip's pins.

Article: YM3812 Part 2: FACE Reveal

Introduces a basic implementation of the YM3812 circuit controlled by an AVR128DA28 microcontroller that we will build on in future articles. Think of it as a "Hello World" starting point that ensure the circuit works and that we can upload code to the microcontroller.

Article: YM3812 Part 3: Behind the Code

Walks through the implementation of the YM3812 class used in Part 2 and describes how each of the register manipulation functions work.

Article: YM3812 Part 4: MIDI Journey

Adds a MIDI input to our schematic, and discusses how to translate MIDI note numbers into frequencies the YM3812 understands

Article: YM3812 Part 5: MIDI Polyphony

Adds Polyphony to our breadboard module, walking through a couple of algorithms in the process.

Article: YM3812 Part 6: Patches

Revise the YM3812 class implementation to support more generic instrument definition

Article: YM3812 Part 7: Percussive Maintenance

Add General MIDI drum support by linking different drum sounds to different notes on the keyboard

Article: YM3812 Part 8: Velocity Sensitivity

Add touch sensitivity to the module by selectively scaling the right operator levels

Article: YM3812 Part 10: Pitch Bend

Add pitch bend capabilities and shred on a YM3812