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Type Conceptual schematic Control pins Notes
Input Potentiometer (2-wire)—In this setting, the external
potentiometer is connected merely as a rheostat—a
variable resistor. The internal pullup resistor is enabled,
so the variable resistor delivers a variable voltage to
the GPIO input; the GPIO circuitry interprets the voltage
as a proportion between minimum and maximum.
This configuration also requires calibration of the pot’s
minimum and maximum positions.
Calibrate Maximum
Calibrate Minimum
Maximum Position
Minimum Position
Calibrate the minimum
and maximum positions of
the pot.
Analog Input (0–24V, low Z)—In this setting the
GPIO reads the positive analog voltage presented to its
input terminal.
Raw—Combines features of both analog and digital
inputs.
Pullup enable See the tech note pertain-
ing to the Raw input.
Output Digital Output (TTL 3.3 V)—The output feeds a 3.3 V
TTL digital input or its equivalent. The two states are
logic high (1) and logic low (0).
Open Collector (200 mA)—In this setting each output
can sink up to 200 mA of current, making it suitable to
actuate the low side of a relay (shown), LED, or other
device. A relay, for example, can be used to switch
higher levels of voltage or current.
CAUTION: The GPIO output is not fused. Current greater
than 200 mA can damage it.
For 12 V relays or other
loads, use the +12 V
source provided. For high-
er-voltage relays or loads,
use an external DC supply
(up to 24 V).
Raw—Similar to the Digital Output setting, except it
offers an “invert”option.
Invert See the tech note pertain-
ing to the Raw output.
Application Examples
Shure MX396/C Microphone Button/Light Clockaudio CH32 Touch Sensitive Switch
Purpose: To convey switch actuations to the Core and turn the mic’s status
light either red or green (the LED cannot be turned off), as directed by the
Core’s GPIO output.
The mic receives phantom power from the Core 110f. The Core 110f can
accommodate as many as 16 MX396/C mics.
Set the GPIO input and output both to Digital.
Mic DIP switch settings:
1 Down
2 Either (does not matter)
3 Up
Purpose: To convey switch actuations to the Core and turn the LED ring of the
Clockaudio CH32 touch sensitive switch either red or green.
As many as three CH32 switches can share the same +12V and GND pins. A
Core 110f can only power as many as six CH32 switches; a suitable external
12V power supply, though, may allow as many as eight switches.
Set GPIO input to Contact Closure. Set both GPIO outputs to Digital.