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1. Introduction of GSM/GPRS ATC-E12

ATC-E12 Easy is a product designed by AT-COM to provide users with integrated facilities that are interconnected into a network through ATCBus.

The power of the board is expressed through the U-blox G450 module with features of GSM, GPRS.

The G450 module is the latest 2G series, delivering optimum performance in SMS, data and voice communications even in harsh environments. The ATC-E12 is full of features to provide you with ideas for wireless-based applications.

2. Schematic of ATC-E12

3. Feature of GSM/GPRS ATC-E12

a. Module ATC-E12

The G450 integrates 2G's advanced technologies into ATCE-E12 module. The ATCE-E12 module is product line with dual-band GSM and GPRS capabilities and can connected to the U-blox GNSS module via the SCL and SDA pins of the ATC-BUS

The ATCBus Socket with integrated pins allows users to connect to products that support ATCBus easily. All in one ATCBus.

b. Power supply and ON/OFF module Sara G450

The SARA G450 module has to be powered by a clean and stable power supply. Power supply for ATC-E05 Easy via ATCBus at two pins 5V and GND. This power will supply for power IC to convert to 4.0Vto supply for the SARA G450 module. This power provides up to 1.6A and drop voltage when the load does not exceed 400mV.

Although the SARA-G450 is a low power device, the cellular network modules in general, are notorious for their highpower consumption, so the 1A LDO had to be used

Some main feature of power IC RT9048:

Default module Sara G340 can switch on after supply 5V@2A power at pin 5V of ATC-E12.

The circuit is designed with a transistor turns on Sara G450 module. It is possible to power on/off Sara G450 module in three Methods:

• Method 1: Use the On/Off button on the circuit.
• Method 2: Provide a high-level pulse for at lest 2s to the PWR pins of the ATCBus Socket, the Sara G450 module will be powered on.
• Method 3: Use AT+CPWROFF command to on module.

c. Logic voltage selection

To communicate with external devices with logic 5V/3V, the board has a custom designed user interface with 3.3V/5V logic voltage for application. When manufacturing, the default logic voltage is 3.3V logic level.

ATC-E12 use bidirectional logic translator TXB0106PWR of Texas Instruments, it can use to convert logic level from 1.2~3.6V to 1.65~5.5V and bidirectional with speed up to 100Mbps. Logic level communicate of Sara G450 is 1.8V and level logic of microcontroller normal is 3.3V/5V, so voltage translator IC need to use to compatible signal level.

ATC-E12 support UART to external device communicate with Sara G450 module via AT commands. UART interface supports baud rates from 2400 bps to 115.2 kbps and automatic baud rate detection for up to 9600bps. The automatic baud rate detection mode is set by default.

At default mode, Sara G450 can’t communicate with external device via UART interface. To enable this function need to pull up WKP pin of ATC-E12 to high level

How to change the communication voltage:

• Remove the 0R resistor (size 0603) at the unwanted position.
• Solder the 0R resistor (size 0603) to the desired position of 3.3V or 5V.

d. Audio and MIC port

The SARA-G450 module offers extensive audio features, including half rate, full rate, enhanced full rate and adaptive multi-rate voice codecs, superior echo cancellation and noise reduction, multiple pre-programmed audio profiles, specialized hands-free algorithm, all configurable with the AT commands. The audio DSP section is integrated inside the module and it requires only a few external components. The headset can be connected via the 4-pole 3.5mm audio jack. With ATCE-12 user can use this application audio via the 4-pole 3.5mm audio jack.

e. Antenna cho GSM/GPRS

Module Sara G450 support for Europe/Asia dual band (900/1800Hz) and data rate up to 85.7kbit/s. Module has 50Ω smd antenna pad, with this function user can add some components to make own GSM/GPRS application.

With the design of the ATC-E12 supports 2 type Antenna GSM are through hole connector and SMD connector for users can choose the antenna type for their applications.

f. LED Indicator

4. Dimention