MIDI-IN-OUT

Features

• Module for Prototyping Synthesizer components
• MIDI In/Out Jacks
• Opto-isolated MIDI Input
• 5V MIDI interface
• 3.3V or 5V Serial connections
• MIDI In is opto-isolated
• (2) 4-40 Mounting holes

Connectors

J1 - MIDI In

• Opto-isolated input

J2 - MIDI Out

J3 - Serial/Power

• Pinout

1. V1 (3.3V or 5V
2. 5V
3. Receive data (out of card)
4. Transmit (in to card)
5. GND

J4 - Short V1 to 5V

• Short J3-1 to J3-2
• Used when Host Serial interface is 5V
• Open when Host Serial interface is 3.3V

Drive Circuit

• 4N25 Optocoupler
• DC Current Transfer Ratio

• LED Current vs voltage

• Output transistor capacitance

• Switching Time

• Vf(LED) = 1.2V
• R(total) = 220 * 3 = 660 Ohms
• V(drive) = 5V
• I(LED) = 5.7 mA
• CTR = 50%