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Q-SYS™ Peripheral Technical Notes
I/O-8 FLEX
Using the GPIO inputs and outputs
The Q-SYS I/O-8 Flex features General Purpose Input/Output (GPIO) connections that allow the
Q-SYS network to interface with miscellaneous outside devices, such as LED indicators, switches,
relays, and potentiometers, and with custom or third-party controls. The GPIO allotment on the I/O-8
Flex totals eight inputs and eight outputs. Use Q-SYS Designer to select the type of input or output
and configure it. Each GPIO input and output is independent of the others.
Flanking each row of eight GPIO inputs and outputs is a +12 V DC terminal (up to 100 mA available
on each, protected by a self-resetting fuse) and a ground or reference terminal. This can be used for
potentiomenters (input), relay coils and LEDs (output), and other uses.
GPIO configurations
These are the various ways that GPIO inputs and outputs can be configured.
Type Conceptual schematic Control pins Notes
Input Digital Input (TTL 3.3 V)—The input is fed by
a 3.3 V TTL digital source. The two states are logic high (1)
and logic low (0).
None
Contact Closure Input—This setting enables
an internal pull-up resistor, allowing actuation by a contact
closure to ground. This can be through a switch, set of relay
contacts, etc.
Potentiometer (10 kΩ, 12V)—In this
setting, the external potentiometer acts as a variable
voltage divider. The GPIO input reads the voltage delivered.
The ground terminal is the reference. The GPIO interprets
the voltage as a proprtion between the minimum and
maximum pot positions, with better resolution and accuracy
than the two-wire potentiometer configuration offers. This
configuration requires calibration of the pot’s minimum and
maximum positions.
None Internal pull-up resistor to
• Calibrate Maximum
• Calibrate Minimum
• Maximum Position
• Minimum Position
+12 V. When contacts are
closed, GPIO In = 0V; when
open, GPIO In = +12V.
Calibrate the minimum and
maximum positions of the
pot.
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Q-SYS™ Accessory Technical Notes
to mic
I/O-8 FLEX
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.
Analog Input (0–24V, low Z)—In this setting
the GPIO reads the positive analog voltage presented to its
input terminal.
• Calibrate Maximum
• Calibrate Minimum
• Maximum Position
• Minimum Position
Calibrate the minimum and
maximum positions of the
pot.
Raw—Combines features of both analog and digital
inputs.
Pullup enable See the tech note pertaining
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 (100 mA)—In this setting
each output can sink up to 100 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 100 mA can damage it.
Raw—Similar to the Digital Output setting, except it
offers an “invert” option.
Invert See the tech note pertaining
Application Examples
Shure MC396 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 I/O-8 Flex. The I/O-8 Flex can accommodate
as many as eight MC396 mics.
Set the GPIO input and output both to Digital.
Mic DIP switch settings:
1 Down
2 Either (does not matter)
3 Up
red
black
bare
I/O-8 FLEX
GPIO Input
GPIO Output
Ground
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 I/O-8 Flex
can power no more than three CH32 switches; a suitable external 12V power supply,
though, may allow four switches.
Set GPIO input to Contact Closure. Set both GPIO outputs to Digital.
I/O-8 FLEX
to mic
RJ45
pin 2
pin 3
pin 4
pin 5
pin 6
GPIO Output (Red LED)
Ground
+12 V
GPIO Input (Button)
GPIO Output (Green LED)
to the Raw input.
For 12 V relays or other
loads, use the +12 V source
provided. For higher-voltage
relays or loads, use an
external DC supply (up to
24 V).
to the Raw output.
qsc.com
Revision A—12 September 2017
© 2017 QSC, LLC. All rights reserved. QSC, and the QSC logo are registered
trademarks in the U.S. Patent and Trademark Office and other countries. #44 V.6
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