Schematic Overview:Midi, Sync and USB
Most of it is pretty simple. A block diagram would be redundant, as it would show inputs leading to outputs, with exception to the USB, where it goes through the USB chip first.
These are pretty simple. Mix In and Out both me through J7 and are connected directly to their respective jacks. CV and gate come thorugh J6, and again, are connected directly to their respective jacks.
DinSync is a single sync connector which doubles as a Sync In and Sync Out. Someone needs to dig into the FirmWare and figure out just which sync lines are in and out.
Midi Out send 5V on pin 4 of the jack. The midi data comes straight from the MicroProcessor and then through a 220 Ohm resistor to pin 5.
Midi In is properly opto-isolated. The Midi signal comes in through the jack, and then goes through a LED in the optoisolator, which activates the base of the PhotoTransistor, allowing current to flow from the collector to the emitter. From the emitter, it enters the base of Q50, Which shorts thhe connection of the +5 Volts to ground. This midi signal is split, one is sent through a 220 Ohm resistor and them the Midi Thru, and the other to the MicroProcessor.
A majority of the circuitry here is straight from the datasheet, which is available here: http://web.media.mit.edu/~ladyada/techproj/USB232/ft232_DS.pdf
|Schematic||Power Supply||Voltage Controlled Oscillator||Voltage Controlled Filter||Envelope Generator||Voltage Controlled Amplifier||Headphone And Mixer||Digital Sequencer||Midi, USB and Sync|
|Fabrication||Building the Ps||Building the Vco||Building the Vcf||Building the Envelope||Building the Vca||Building the Headphone And Mixer||Building the Sequencer||Building the Midi and Sync||Finishing It Off|
|Testing||Testing the Ps||Testing the Vco||Testing the Vcf||Testing the Envelope||Testing the Vca||Testing the Headphone And Mixer||Testing the Sequencer||Testing the Midi and Sync|
|Mods||Ps Mods||Vco Mods||Vcf Mods||Envelope Mods||Vca Mods||Headphone And Mixer Mods||Sequencer Mods||Midi And Sync Mods||Finishing Mods|