Telit Wireless Solutions GE863-PY 2MODEM Serial Port 2 Python Debug, 3RS232 level translation

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GE863-QUAD

GE863-PY

1vv0300715 Rev. 1 - 19/09/06

6.2MODEM SERIAL PORT 2 (Python Debug)

It is available on the following pins:

PIN #	NAME	DESCRIPTION	TYPE
25	TX_TRACE	TX Data	CMOS 2.8V
26	RX_TRACE	RX Data	CMOS 2.8V

6.3RS232 level translation

In order to interface the Telit GE863-QUAD/PY with a PC com port or a RS232 (EIA/TIA-232) application a level translator is required. This level translator must

•invert the electrical signal in both directions

•change the level from 0/3V to +15/-15V

Actually, the RS232 UART 16450, 16550, 16650 & 16750 chipsets accept signals with lower levels on the RS232 side (EIA/TIA-562) , allowing for a lower voltage-multiplying ratio on the level translator. Note that the negative signal voltage must be less than 0V and hence some sort of level translation is always required.

The simplest way to translate the levels and invert the signal is by using a single chip level translator. There are a multitude of them, differing in the number of driver and receiver and in the levels (be sure to get a true RS232 level translator not a RS485 or other standards).

By convention the driver is the level translator from the 0-3V UART level to the RS232 level, while the receiver is the translator from RS232 level to 0-3V UART.

In order to translate the whole set of control lines of the UART you will need:

•5 driver

•3 receiver

NOTE: The digital input lines working at 2.8VCMOS have an absolute maximum input voltage of 3,75V; therefore the level translator IC shall not be powered by the +3.8V supply of the module. Instead it shall be powered from a +2.8V / +3.0V (dedicated) power supply.

This is because in this way the level translator IC outputs on the module side (i.e. GE863- QUAD/PY inputs) will work at +3.8V interface levels, stressing the module inputs at its maximum input voltage.

This can be acceptable for evaluation purposes, but not on production devices.

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Contents GE863-QUAD GE863-PY Hardware User Guide Contents 10.3 10.110.2 10.413.2 12.113.1 This document is relating to the following products Overview GE863 module connections PIN-OUTPin Signal Function Internal Type Pull up Pin Signal Function Internal Type Pins Layout Hardware Commands Turning on the GE863-QUAD/PYTurning OFF the GE863-QUAD/PY Turning off of the device can be done in two waysHardware Unconditional Reboot Hardware shutdownGE863-QUAD GE863-QUAD/PY power requirements are Power Supply1Power Supply Requirements 2General Design Rules Electrical design Guidelines1.2 + 12V input Source Power Supply Design Guidelines An example of linear regulator with 5V input isBattery Source Power Supply Design Guidelines An example of switching regulator with 12V input isBattery Charge control Circuitry Design Guidelines Thermal Design Guidelines Power Supply PCB layout Guidelines Antenna GSM Antenna RequirementsGSM Antenna PCB line Guidelines GSM Antenna installation GuidelinesSerial Ports Absolute Maximum Ratings -Not Functional Parameter Min Max Level Min Max17-28-36 Ground 45-48-50-56 Signals in the Uart connector on the EVK areNumber Pad Number Clear to Send Output from the GE863-QUAD/PY that3RS232 level translation It is available on the following pins2MODEM Serial Port 2 Python Debug An example of level translation circuitry of this kind is 5V Uart level translation GE863-QUAD Audio Section Overview GM863-GPS Echo canceller type Car kit hands-free Microphone Paths Characteristic and RequirementsEcho canceller type Handset + 20dBThat means You can set GA= +20dB to use standard resistor valuesTIP environment consideration General Design Rules Other considerationsMicrophone Biasing Balanced Microphone BiasingUnbalanced Microphone Biasing GE863-QUAD Sample circuit can be Microphone BufferingBuffered Balanced Mic Gain = RR604605 = RR607606 Buffer gain is given by the formulaBuffered Unbalanced Single Ended Microphone Freq . = 2π * R719* C726 2π * R711* C727 Buffer bandwidth at -3dB shall be 4KHzGE863-QUAD Output Lines Speaker Short descriptionOutput Lines Characteristics SW volume level step Number of SW volume stepsNoise Filtering Handset Earphone Design Hands-Free Earphone Low Power Design An example of internal Ear amplifier could beCar Kit Speakerphone Design Evaluation Kit for Telit Modules EVK2 Short Description2 EVK2 Audio Lines Characteristics @ 350mWData Integrity ESDSchematic SIM SupplyLayout General Purpose I/O Using a Gpio Pad as InputUsing a Gpio Pad as Output 10.3Using the Alarm Output GPIO6 Using the Buzzer Output GPIO7Description DAC and ADC section11.1DAC Converter Min Max UnitsEnabling DAC An AT command is available to use the DAC functionCommand is AT#DAC=enable,value Low Pass Filter Example11.2ADC Converter Using ADC ConverterInput Voltage range AD conversion Bits Resolution Type Camera12.1Transchip Camera Sensitivity LuxCamera Interface Connectors Camera Physical Detail & Connector Camera Socket Connector Camera Board Module Main Block Diagram for supported cameras Schematic Diagrams for supported camera Taking an reading a photo Camera setting shown here are the defaults onesExample usage script for camera 13.1General 13.2Module Finishing & DimensionsMounting the GE863-QUAD / PY on the Application Board Surface finishing Ni/Au for all test pads Lead-free AlloyRecommended foot print for the application PCB pad Design Debug of the GE863 in ProductionStencil Solder paste 13.2.6 GE863-QUAD / PY Solder Reflow Following is the recommended solder reflow profileGE863-QUAD Packing System Section A-AModules orientation on tray Moisture Sensibility Conformity Assessment Issues Safety Recommandations 21/02/06 Document Change LogRevision Date Changes 19/09/06