User's Manual

The UART2 used as transmitting DATA between the module from user, only supply 2 signals

as follow table:

Pin name DIR Pin Number Function unit

TXD2 O 21 UART 2 data transmitting port

RXD2 I 22 UART 2 data receiving port

This module also support baud rate from 9600 to 921600

6.5 GPIOs

The GT2GM-M module has 8 GPIOs (PIN8,PIN18,PIN24,PIN25,PIN27, PIN28, PIN30,PIN30): Please

refer to corresponding programming application for details as to all the GPIO ports.

6.6 LED

GT2GM-M module has 2 LED driver pin(pin23 & pin29), please ref. the following sch

6.7 SIM card interface

In the Current Version of hareware,The module includes a SIM Socket.When the user use

this interface,You must use the Voltage Dependent Resistor (VDR) or TVS component

on the

transmission signal in the same time.The SIM Card digital interface in the GT2GM-M ensures the

translation of logic levels between GT2GM-M and the SIM Card, for the transmission of 3

different signals: clock signal (SIMCLK,PIN12), reset signal (SIMRST,PIN13) from GT2GM-M

to the SIM Card; and serial data signal from GT2GM-M to the SIM Card (SIMDATA,PIN11). The

SIM card interface can be programmed to drive a 3.0V SIM Card. Importance that the Voltage

Dependent Resistor (VDR) or TVS component is necessary on the transmission signal , and the

bias cap is lower than 30pF was suggested. The bypass cap of VCC net was suggested 1uF, and it

must be added in your design.