User guide

Chapter 1 – Product Description and Specifications
Multi-Tech Systems, Inc. MultiModem iCell Intelligent Wireless Modem User Guide 11
GPIO (General Purpose Input/Output) 6-Pin
Connector
The GPIO pins are configured using Universal IP (UIP) AT Commands. Refer to the Universal IP (UIP) AT Command Reference
Guide on your MultiModem CD. The following table explains the GPIO functions:
Pin
Number
Description GPIO 6-Pin
Connector
Pin 1 DIO 0
Pin 2 DIO 1
Pin 3 DIO 2 / ADC 0
Pin 4 DIO 3 / ADC 1
Pin 5 ADC 2
Pin 6 Gnd
The GPIO pins can be configured independent of each other. An explanation of the difference between the Rev B and Rev C
boards is provided in the Back Panel description in Chapter 1.
● Pin 1 Digital Input (5V tolerant TTL/CMOS levels) for Rev B, 24 Volt tolerent for Rev C and later.
● Pin 2 Digital Input (5V tolerant TTL/CMOS levels) for Rev B, 24 Volt tolerent for Rev C and later.
● Pin 3 can be configured as either Digital Input (5V tolerant TTL/CMOS levels) or Digital Output (3.3V High) or as an
ADC input (0 to 3.3V rail)
● Pin 4 can be configured as either Digital Input (5V tolerant TTL/CMOS levels) or Digital Output (3.3V High) or as an
ADC input (0 to 3.3V rail)
● Pin 5 is configured as an ADC input (0 to 3.3V rail)
● Pin 6 is GND and must be connected to the ground of the attached device
GPIO DC Characteristics
Pins 1,2 - Rev B Board
Input Voltage
Parameter Min Max Units
Input Low-level Voltage -0.3 0.8 V
Input High-level Voltage 2.0 5.5 V
Pins 1,2 - Rev C and later Board
Input Voltage
Parameter Min Max Units
Input Low-level Voltage 0.3 1.0 V
Input High-level Voltage 3.0 24 V
Pins 3,4
Input Voltage
Parameter Min Max Units
Input Low-level Voltage -0.3 0.8 V
Input High-level Voltage 2.0 5.5 V
Pins 3, 4
Output Voltage
Parameter Min Max Units
Output Low-level Voltage 0.0 0.4 V
Output High-level Voltage 2.9 3.3 V
Pins 3,4
Output Current
Parameter Min Max Units
Output Current 2 mA
Pins 1,2 are digital input only
Pin 5 is an analog input only
Pins 1-5 contain ESD protection