There are 3 major sections to the x0xb0x. The PowerSupply, the analog synthesizer and the DigitalSequencer.
The PowerSupply lives on the IoBoard takes the ~9 volt AC power, splits it into two sections. One of them rectifies it to 5 volts and 6 volts, the other section references it to 5.333 volts, and doubles it to 12 volts.
The analog synthesizer lives on the MainBoard and has five major sections. First off is the VoltageControlledOscillator, which takes an input from the DigitalSequencer, and creates a SquareWave or a SawWave from it. It then sends this waveform to the VoltageControlledFilter, which also takes an input from the EnvelopeGenerator to perform the LowPassFilter and Accent. After that it sends its signal to the VoltageControlledAmplifier, which also gets an input from the EnvelopeGenerator to affect the volume of the notes. Finally this is sent out to the HeadphoneAndMixer section for amplification and mixing.
The DigitalSequencer also lives on the MainBoard has 3 sections. The first and foremost is the MicroProcessor, which is responsible for controlling the thing, and also has the FirmWare burnt into it. There is also the rest of the DigitalSequencer consisting of the Switches, Tempo Knob, Rotary Knobs and LEDs. Finally there is the MidiAndSync section which lives on the IoBoard.
Here is a general visual overview of the x0xb0x schematic. Each of the subsections above have their own block diagrams as well.
<draw name=schematicblock namespace=x0x>
I am working (slowly) on putting up a schematic of each section on the individual section pages. This is gonna take a little while, so bear with me. – Jonnay