Polycom SoundStructure C16 Design Manual page 252

The value of a logic input array is read with the digital_gpio_value parameter. If a logic pin is part of
an array, it may not also be used as an individual logic input pin.
Defining Logic Arrays for TwoPinArray
Logic output arrays may also be defined. The value of a logic output array is set using the digital_gpio_value
parameter. For example if three logic output pins are part of a logic output array, the command
set digital_gpio_value "Output Array" 7
sets all of the pins in the array named "Output Array" to the value 1.
Viewing the LED Example
The following figure is an example of how to use an external LED. Most standard LEDs require
approximately 2.0 V to illuminate. In this example a 274 ohm resistor is used to limit the current from the 5V
supply of Pin 1and to limit the voltage and current to a safe level for the LED. Increasing the series resistor
value decreases the current through the circuit and also decreases the voltage at the input to the LED,
reducing the brightness of the LED.
Polycom, Inc. 252