Polycom C12, C16, C8, SR12 - page 27

Installing The SoundStructure C16, C12, C8, And SR12
2 - 17
Logic Inputs
All digital logic inputs (logic inputs 1 - 22) operate as contact closures and may
either be connected to ground (closed) or not connected to ground (open). The
logic input circuitry is shown in the following figure. Chapter 4 Logic
Examples provides examples of how to use the logic input pins.
Analog Gain Input
The analog gain inputs (analog gain 1 and 2) operate by measuring an analog
voltage between the analog input pin and the ground pin. The maximum input
voltage level should not exceed +6 V. It is recommended that the +5 V supply
on Pin 1 be used as the upper voltage limit.
The following figure shows the analog gain input pin and the associated +5 V
and ground pins that are used with the analog gain input pin. The analog
voltage on the analog gain input pin is converted to a digital value via an 8-bit
analog-to-digital converter for use within the SoundStructure devices. The
maximum voltage value, i.e., 0 dBFS on the analog gain input, is 4.096 V. The
SoundStructure API commands analog_gpio_min and analog_pio_max are
used to map the values into a desired range of numerical values. By default 0
V is converted to 0 and 4.096 V and above is converted to 255.
8 Logic Output 18 21 Logic Input 19
9 Logic Output 19 22 Logic Input 20
10 Logic Output 20 23 Logic Input 21
11 Logic Output 21 24 Logic Input 22
12 Logic Output 22 25 Ground
13 Analog Gain 2
Logic
Status
SoundStructure Logic Input
Logic Input Pin
Logic Pin 25 (Ground)
3.3V