Doepfer USB64 Universal Midi and USB Controller Electronics Kit - Manual (Page 10)

Page 10 User's Guide V1.3 USB64
In both cases an additional resistor is required (possible range 4k7 to 100k) to pull the analog
input to a defined state during the switch is open.
•
Version 1: The resistor is soldered between GND and the control voltage input. This way the
input is pulled to GND ( =0V corresponding to Midi data 0) as long as the switch is left open.
When the switch is closed the voltage jumps to +5V corresponding to Midi data 127.
•
Version 2: The resistor is soldered between +5V and the control voltage input. This way the
input is pulled to +5V (corresponding to Midi data 127) as long as the switch is left open.
When the switch is closed the voltage jumps to 0V corresponding to Midi data 0.
64 resistors (range 4k7 ... 100k) are enclosed witch each USB64 delivery. Suitable resistors are
available in each electronic shop too (value: ~ 10k, power: ¼ W, tolerance: 5%, material:
carbon).
Unused inputs have to be connected to GND or +5V. Avoid open inputs ! An open input will
cause the transmission of random Midi data causing undesirable side effects at the Midi
receiver (e.g. Midi overflow or random parameter fluctuations).
Connection of a momentary or
toggle switch (version 1)
Connection of a momentary or
toggle switch (version 2)