1. Introduction of ATC-E07
ATC-E07 Easy is a product designed by AT-COM to provide users with integrated facilities that are interconnected into a network through ATCBus.
The SARA-U270 module is the latest 3G/2G series, delivering optimum performance in SMS, data and voice communications even in harsh environments. The ATC-E07 is full of features to provide you with ideas for wireless-based applications.
2. Schematic of ATC-E07
3. Feature of ATC-E07
a. Module ATC-E07
The U-blox SARA-U270 integrates 3G's advanced technologies into ATC-E07 module. The ATC-E07 module is product line with 3G technology and back ward to 2G capabilities. The U-blox SARA-U270 can connect to the U-blox GNSS module via the SCL and SDA pins of the ATC-BUS.
Some feature of module Ublox-SARA U270:
The ATCBus Socket integrate pins allows users to connect to products that supports ATCBus easily. All in one ATCBus.
b. Power supply and ON/OFF module Sara U270
The SARA-U270 module has to be powered by a clean and stable power supply. Power supply for ATC-E07 via ATCBus at two pins 5V and GND. This power will supply for power IC RT9048 of Ricktek to convert to 3.8V to supply for the SARA U270 module. This power provides up to 1.9A and drop voltage when the load does not exceed 400mV.
Although the SARA-U270 is a low power device, the cellular network modules in general are notorious for their high-power consumption, so the 2A LDO had to be used
Some main features of power IC RT9048:
Default, SARA-U270 can swiched on after supply 5V@2A power at pin 5V of ATC-E07. The circuit is designed with a transistor to turns on SARA-U270 module via pin PWK of ATCBus. It is possible to power on/off SARA-U270 module in three Methods:
Method 1: After module is powered off, press the ON / OFF button on the circuit and release about 2s to power on module.
Method 2: Provide a high-level pulse for at least 2 second to the PWR pins of the ATCBus Socket, the SARA-U270 module will be powered on.
Method 3: Use AT+CPWROFF command to OFF module.
c. Logic level voltage selection
To communicate with external devices with logic 5V/3V, the board has an interface with 3.3V/5V logic voltage selection for user can choose depend their application. When manufacturing, the default logic voltage is 3.3V logic level.
ATC-E07 uses bidirectional logic translator TXS0106EPW 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-U270 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-E07 supports UART to external device communicate with SARA-U270 module via AT command. UART interface supports baud rates from 2400 bps to 115.2 kbps and automatic baud rate detection. The default baud rates is 9600 kbps.
At default mode, SARA-U270 can’t communicate with external device via UART interface. So, to enable this function need to pull up WKP pin of ATC-E07 to high level logic. If logic level communication is 3.3V, need to connect pin 3V3 of ATCBus to 3.3V.
How to change the communication voltage:
d. Audio and MIC port
SARA-U270 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.
SARA U-270 offers the I2S interface, mainly used for digital audio. The MAX9860, a 16bit mono audio voice CODEC IC from Maxim Integrated, provides the 3G SARA click board with the voice communication. This IC uses the I2S and I2C interfaces to communicate with the SARA U-270 module. This IC provides a clean and audible analog interface for connecting the headset, with one audio output channel and one microphone input channel. The headset can be connected via the onboard 3.5mm audio jack.
Some functions of MAX9860ETG+T:
e. Antenna GSM/ GPRS
Module SARA-U270 support for GSM band with 900/1800MHz and HSPA band with 850, 900, 1900, 2100MHz with data rate up to 72Mbps. Module has 50Ohm smd antenna pad, with functions for user can add some components to make own 3G/GSM/GPRS application.
ATC-E07 supports SMD IPX connector antenna for users can connect to external 3G antenna and make for their applications.
f. LED Indicator
g. USB Interface
ATC-E07 is equipped with the micro USB connector of MUP. It allows the module to be configured by a personal computer (PC). U-blox company offers a software suite that can be used to configure the SARA-U270 module. User can download m-center software tool on U-blox website and use this tool to communicate with ATC-E07 via micro usb connector on board.