Polycom SoundStructure C16 Hardware Installation Manual page 28

Hardware Installation Guide for the Polycom SoundStructure C16, C12, C8, And SR12
2 - 18
7 Logic Output 17
8 Logic Output 18
9 Logic Output 19
10 Logic Output 20
11 Logic Output 21
12 Logic Output 22
13 Analog Gain 2
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.
SoundStructure Logic Input
Logic
Status
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.
20 Logic Input 18
21 Logic Input 19
22 Logic Input 20
23 Logic Input 21
24 Logic Input 22
25 Ground
3.3V
Logic Input Pin
Logic Pin 25 (Ground)