Telit Communications S p A GM862 Data Terminal Module User Manual

Telit Communications S.p.A. Data Terminal Module

UserManual.wiki >

Telit Communications S p A >

GM862 User Manual HTML Version

User Manual

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

-Q

D-

-P

Telit Communications S.p.A. 2005

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

Contents

1 OVERVIEW 4

2 HARDWARE COMMANDS 5

2.1 Turning ON the GM862-QUAD 5

2.2 Turning OFF the GM862-QUAD 7

2.2.1.1 Hardware shutdown 7

2.2.1.2 Hardware Unconditional Reset 7

3 POWER SUPPLY 9

3.1 Power Supply Requirements 9

3.2 General Design Rules 9

3.2.1 Electrical design Guidelines 10

3.2.1.1 + 5V input Source Power Supply Design Guidelines 10

3.2.1.2 + 12V input Source Power Supply Design Guidelines 11

3.2.1.3 Battery Source Power Supply Design Guidelines 12

3.2.1.4 Battery Charge control Circuitry Design Guidelines 12

3.2.2 Thermal Design Guidelines 14

3.2.3 Power Supply PCB layout Guidelines 15

4 SERIAL PORT 17

4.1 RS232 level translation 19

4.2 5V UART level translation 21

5 MICROPHONE 23

5.1 Microphone line Characteristic and requirements 23

5.2 General Design Rules 26

5.3 Microphone Biasing 26

5.3.1 Balanced Microphone biasing 27

5.3.2 Unbalanced Microphone biasing 28

5.4 Microphone buffering 29

5.4.1 Buffered Balanced Mic. 29

5.4.2 Buffered Unbalanced (Single Ended) Mic. 31

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

6 SPEAKER 34

6.1 Speaker lines characteristics and requirements 34

6.2 General Design rules 36

6.2.1 Noise Filtering 36

6.3 Handset earphone design 36

6.4 Hands Free earphone (low power) design 38

6.5 Car Kit speakerphone design 38

7 GENERAL PURPOSE I/O 40

7.1 Using a GPIO pin as INPUT 40

7.2 Using a GPIO pin as OUTPUT 40

7.3 Using the Alarm Output GPIO6 41

7.4 Using the Buzzer Output GPIO7 41

8 CAMERA 42

8.1 Agilent Camera 42

8.1.1 Camera interface connectors 42

8.1.2 EVB for camera support 44

8.2 Camera Transchip 45

8.2.1 Camera interface connectors 45

8.2.2 EVB for Agilent and Transchip camera support 47

8.2.3 Block Diagram for supported cameras 48

8.2.4 Schematic Diagrams for supported cameras 49

8.2.5 Example usage script for camera 51

9 DOCUMENT CHANGE LOG 52

10 ANNEX A - EVK SCHEMATICS 53

11 ANNEX B - CAMERA EVB SCHEMATICS 65

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

1 Overview

The aim of this document is the description of some hardware solutions useful for developing a

product with the Telit GM862-QUAD/-QUAD-PY modules.

In this document all the basic functions of a mobile phone will be taken into account; for each one

of them a proper hardware solution will be suggested and eventually the wrong solutions and

common errors to be avoided will be evidenced. Obviously this document can not embrace the

whole hardware solutions and products that may be designed. The wrong solutions to be avoided

shall be considered as mandatory, while the suggested hardware configurations shall not be

considered mandatory, instead the information given shall be used as a guide and a starting point for

properly developing your product with the Telit GM862-QUAD/-QUAD-PY modules. For further

hardware details that may not be explained in this document refer to the GM862-QUAD/-QUAD-

PY Product Description document where all the hardware information is reported.

NOTE: In this document all the hardware solution are referenced to the GM862-QUAD.

As a general rule, since all the product line GM862-QUAD, GM862-QUAD-PY is pin to pin

hardware compatible, all these solutions apply also to the GM862-QUAD-PY.

NOTE

The information presented in this document is believed to be accurate and reliable. However, no responsibility is

assumed by DAI Telecom for its use, nor any infringement of patents or other rights of third parties which may result

from its use. No license is granted by implication or otherwise under any patent rights of DAI Telecom other than for

circuitry embodied in Telit products. This document is subject to change without notice.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

2 Hardware Commands

2.1 Turning ON the GM862-QUAD

To turn on the GM862-QUAD the pin ON# must be tied low for at least 1 second and then released.

The maximum current that can be drained from the ON# pin is 0,1 mA.

A simple circuit to do it is:

NOTE: don't use any pull up resistor on the ON# line, it is internally pulled up. Using pull up resistor

may bring to latch up problems on the GM862-QUAD power regulator and improper power on/off of the

module. The line ON# must be connected only in open collector configuration.

NOTE: In this document all the lines that are inverted, hence have active low signals are labeled with a

name that ends with a "#" or with a bar over the name.

TIP: To check if power has raised it is possible to monitor the START line, when this line goes high the

module is powered on, but before it remains on the device needs other 900 ms for software startup.

Hence check the PWRCTL line and 900 ms after its transition to high it is possible to release the ON#

pin.

ON#

Power ON impulse

GND

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

For example:

1- Let's assume you need to drive the ON# pin with a totem pole output of a +3/5 V microcontroller

(uP_OUT1):

2- Let's assume you need to drive the ON# pin directly with an ON/OFF button:

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

2.2 Turning OFF the GM862-QUAD

The turning off of the device can be done in three ways:

• by software command (see GM862-QUAD Software User Guide)

• by hardware shutdown

• by hardware unconditional shutdown

When the device is shut down by software command or by hardware shutdown, it issues to the

network a detach request that informs the network that the device will not be reachable any more.

The hardware unconditional shutdown does not issue this request and shuts down immediately the

device.

The hardware unconditional shutdown must not be used during normal operation of the device

since it does not detach the device from the network. It shall be kept as an emergency exit

procedure to be done in the rare case that the device gets stucked waiting for some network or SIM

responses.

If device does not respond to a command in the timeout window, retry issuing the command and if

still no response is received a hardware unconditional shutdown shall be issued and then a restart.

2.2.1.1 Hardware shutdown

To turn OFF the GM862-QUAD the pin ON# must be tied low for at least 1 second and then

released.

The same circuitry and timing for the power on shall be used.

The device shuts down after the release of the ON# pin.

TIP: To check if the device has powered off, the hardware line PWRCTL should be monitored. When

PWRCTL goes low, the device has powered off.

2.2.1.2 Hardware Unconditional Reset

To unconditionally turn OFF the GM862-QUAD the pin RESET# must be tied low for at least 200

milliseconds and then released.

The maximum current that can be drained from the ON# pin is 0,15 mA.

A simple circuit to do it is:

RESET#

Unconditional Power OFF

impulse

GND

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

NOTE: don't use any pull up resistor on the RESET# line nor any totem pole digital output. Using pull

up resistor may bring to latch up problems on the GM862-QUAD power regulator and improper

functioning of the module. The line RESET# must be connected only in open collector configuration.

TIP: The unconditional hardware reset should be always implemented on the boards and software

should use it as an emergency exit procedure.

For example:

1- Let's assume you need to drive the RESET# pin with a totem pole output of a +3/5 V

microcontroller (uP_OUT2):

Unconditional Reset

impulse

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

3 Power Supply

The power supply circuitry and board layout are the most important part in the full product design

and they strongly reflect on the product overall performances, hence read carefully the requirements

and the guidelines that will follow for a proper design.

3.1 Power Supply Requirements

The GM862-QUAD power requirements are:

• Nominal Supply Voltage: 3.8 V

• Max Supply Voltage: 4.2 V

• Supply voltage range: 3.4 V - 4.2 V

• Max Peak current consumption (impulsive): 1.9 A

• Max Average current consumption during transmission (rms): 350 mA

• Average current during Power Saving: ≈ 4 mA

• Average current during idle (Power Saving disabled) ≈ 17 mA

The GSM system is made in a way that the RF transmission is not continuous, else it is packed into

bursts at a base frequency of about 216 Hz, the relative current peaks can be as high as about 2A.

Therefore the power supply has to be designed in order to withstand with these current peaks

without big voltage drops; this means that both the electrical design and the board layout must be

designed for this current flow.

If the layout of the PCB is not well designed a strong noise floor is generated on the ground and the

supply; this will reflect on all the audio paths producing an audible annoying noise at 216 Hz; if the

voltage drop during the peak current absorption is too much, then the device may even shutdown as

a consequence of the supply voltage drop.

TIP: The electrical design for the Power supply should be made ensuring it will be capable of a peak

current output of at least 2 A.

3.2 General Design Rules

The principal guidelines for the Power Supply Design embrace three different design steps:

- the electrical design

- the thermal design.

- the PCB layout.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

3.2.1 Electrical design Guidelines

The electrical design of the power supply depends strongly from the power source where this power

is drained. We will distinguish them into three categories:

• +5V input (typically PC internal regulator output)

• +12V input (typically automotive)

• Battery

3.2.1.1 + 5V input Source Power Supply Design Guidelines

• The desired output for the power supply is 3.8V, hence there's not a big difference between the

input source and the desired output and a linear regulator can be used. A switching power

supply will not be suited because of the low drop out requirements.

• When using a linear regulator, a proper heat sink shall be provided in order to dissipate the

power generated.

• A Bypass low ESR capacitor of adequate capacity must be provided in order to cut the current

absorption peaks close to the GM862-QUAD, a 100μF tantalum capacitor is usually suited.

• Make sure the low ESR capacitor on the power supply output (usually a tantalum one) is rated

at least 10V.

• A protection diode should be inserted close to the power input, in order to save the GM862-

QUAD from power polarity inversion.

An example of linear regulator with 5V input is:

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

3.2.1.2 + 12V input Source Power Supply Design Guidelines

• The desired output for the power supply is 3.8V, hence due to the big difference between the

input source and the desired output, a linear regulator is not suited and shall not be used. A

switching power supply will be preferable because of its better efficiency especially with the 2A

peak current load represented by the GM862-QUAD.

• When using a switching regulator, a 500Khz switching frequency regulator is preferable

because of its smaller inductor size and its faster transient response. This allows the regulator to

respond quickly to the current peaks absorption.

• For car PB battery the input voltage can rise up to 15,8V and this should be kept in mind when

choosing components: all components in the power supply must withstand this voltage.

• A Bypass low ESR capacitor of adequate capacity must be provided in order to cut the current

absorption peaks, a 100μF tantalum capacitor is usually suited.

• Make sure the low ESR capacitor on the power supply output (usually a tantalum one) is rated

at least 10V.

• For Car applications a spike protection diode should be inserted close to the power input, in

order to clean the supply from spikes.

• A protection diode should be inserted close to the power input, in order to save the GM862-

QUAD from power polarity inversion. This can be the same diode as for spike protection.

An example of switching regulator with 12V input is:

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

3.2.1.3 Battery Source Power Supply Design Guidelines

• The desired nominal output for the power supply is 3.8V and the maximum voltage allowed is

4.2V, hence a single 3.7V Li-Ion cell battery type is suited for supplying the power to the Telit

GM862-QUAD module.

The three cells Ni/Cd or Ni/MH 3,6 V Nom. battery types or 4V PB types MUST NOT BE

USED since their maximum voltage can rise over the absolute maximum voltage for the

GM862-QUAD and damage it.

NOTE: DON'T USE any Ni-Cd, Ni-MH, and Pb battery types. Their use can lead to overvoltage on the

GM862-QUAD and damage it. USE ONLY Rechargeable Li-Ion battery types.

• A Bypass low ESR capacitor of adequate capacity must be provided in order to cut the current

absorption peaks, a 100μF tantalum capacitor is usually suited.

• Make sure the low ESR capacitor (usually a tantalum one) is rated at least 10V.

• A protection diode should be inserted close to the power input, in order to save the GM862-

QUAD from power polarity inversion. Otherwise the battery connector should be done in a way

to avoid polarity inversions when connecting the battery.

• The battery capacity must be at least 500mAh in order to withstand the current peaks of 2A; the

suggested capacity is from 500mAh to 1000mAh.

3.2.1.4 Battery Charge control Circuitry Design Guidelines

The charging process for Li-Ion Batteries can be divided into 4 phases:

• Qualification and trickle charging

• Fast charge 1 - constant current

• Final charge - constant voltage or pulsed charging

• Maintenance charge

The qualification process consists in a battery voltage measure, indicating roughly its charge status.

If the battery is deeply discharged, that means its voltage is lower than the trickle charging

threshold, then the charge must start slowly possibly with a current limited pre-charging process

where the current is kept very low with respect to the fast charge value: the trickle charging.

During the trickle charging the voltage across the battery terminals rises; when it reaches the fast

charge threshold level the charging process goes into fast charge phase.

During the fast charge phase the process proceeds with a current limited charging; this current limit

depends on the required time for the complete charge and from the battery pack capacity. During

this phase the voltage across the battery terminals still raises but at a lower rate.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

Once the battery voltage reaches its maximum voltage then the process goes into its third state:

Final charging. The voltage measure to change the process status into final charge is very

important. It must be ensured that the maximum battery voltage is never exceeded, otherwise the

battery may be damaged and even explode. Moreover for the constant voltage final chargers, the

constant voltage phase (final charge) must not start before the battery voltage has reached its

maximum value, otherwise the battery capacity will be highly reduced.

The final charge can be of two different types: constant voltage or pulsed.

The constant voltage charge proceeds with a fixed voltage regulator (very accurately set to the

maximum battery voltage) and hence the current will decrease while the battery is becoming

charged. When the charging current falls below a certain fraction of the fast charge current value,

then the battery is considered fully charged, the final charge stops and eventually starts the

maintenance.

The pulsed charge process has no voltage regulation, instead the charge continues with pulses.

Usually the pulse charge works in the following manner: the charge is stopped for some time, let's

say few hundreds of ms, then the battery voltage will be measured and when it drops below its

maximum value a fixed time length charging pulse is issued. As the battery approaches its full

charge the off time will become longer, hence the duty-cycle of the pulses will decrease. The

battery is considered fully charged when the pulse duty-cycle is less than a threshold value,

typically 10%, the pulse charge stops and eventually the maintenance starts.

The last phase is not properly a charging phase, since the battery at this point is fully charged and

the process may stop after the final charge. The maintenance charge provides an additional charging

process to compensate for the charge leak typical of a Li-Ion battery. It is done by issuing pulses

with a fixed time length, again few hundreds of ms, and a duty-cycle around 5% or less.

This last phase is not implemented in the GM862-QUAD internal charging algorithm, so that the

battery once charged is left discharging down to a certain threshold so that it is cycled from full

charge to slight discharge even if the battery charger is always inserted. This guarantees that

anyway the remaining charge in the battery is a good percentage and that the battery is not damaged

by keeping it always fully charged (Li-Ion rechargeable battery usually deteriorate when kept fully

charged).

Last but not least, in some applications it is highly desired that the charging process restarts when

the battery is discharged and its voltage drops below a certain threshold, GM862-QUAD internal

charger does it.

As you can see, the charging process is not a trivial task to be done; moreover all these operations

should start only if battery temperature is inside a charging range, usually 5°C - 45°C.

The GM862-QUAD measures the temperature of its internal component, in order to satisfy this last

requirement, it's not exactly the same as the battery temperature but in common application the two

temperature should not differ too much and the charging temperature range should be guaranteed.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

An example of battery charger can be:

NOTE: In this particular application the battery charger input current must be limited to less than 1A.

This can be done by using a current limited wall adapter as the power source.

For your convenience in the EVK there's also a current unlimited input, where the input source is not

limited in current and the drawn current is limited to about 0,5A by a MOSFET in the EVK.

3.2.2Thermal Design Guidelines

The thermal design for the power supply heat sink should be done with the following specifications:

• Average current consumption during transmission @PWR level max (rms): 350mA

• Average current consumption during transmission @ PWR level min (rms): 100mA

• Average current during Power Saving: 4mA

• Average current during idle (Power Saving disabled) 17mA

NOTE: The average consumption during transmissions depends on the power level at which the

device is requested to transmit by the network. The average current consumption hence varies

significantly.

TIP: The thermal design for the Power supply should be made keeping a average consumption at the

max transmitting level during calls of 350mA rms.

Considering the very low current during idle, especially if Power Saving function is enabled, it is

possible to consider from the thermal point of view that the device absorbs current significantly

only during calls.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

If we assume that the device stays into transmission for short periods of time (let's say few minutes)

and then remains for a quite long time in idle (let's say one hour), then the power supply has always

the time to cool down between the calls and the heat sink could be smaller than the calculated one

for 350mA maximum RMS current, or even could be the simple chip package (no heat sink).

Moreover in the average network conditions the device is requested to transmit at a lower power

level than the maximum and hence the current consumption will be less than the 350mA, being

usually around 150mA.

For these reasons the thermal design is rarely a concern and the simple ground plane where the

power supply chip is placed can be enough to ensure a good thermal condition and avoid

overheating.

3.2.3 Power Supply PCB layout Guidelines

As seen on the electrical design guidelines the power supply shall have a low ESR capacitor on the

output to cut the current peaks and a protection diode on the input to protect the supply from spikes

and polarity inversion. The placement of these components is crucial for the correct working of the

circuitry. A misplaced component can be useless or can even decrease the power supply

performances.

• The Bypass low ESR capacitor must be placed close to the Telit GM862-QUAD power input

pins or in the case the power supply is a switching type it can be placed close to the inductor to

cut the ripple provided the PCB trace from the capacitor to the GM862-QUAD is wide enough

to ensure a dropless connection even during the 2A current peaks.

• The protection diode must be placed close to the input connector where the power source is

drained.

• The PCB traces from the input connector to the power regulator IC must be wide enough to

ensure no voltage drops occur when the 2A current peaks are absorbed. Note that this is not

made in order to save power loss but especially to avoid the voltage drops on the power line at

the current peaks frequency of 216 Hz that will reflect on all the components connected to that

supply, introducing the noise floor at the burst base frequency. For this reason while a voltage

drop of 300-400 mV may be acceptable from the power loss point of view, the same voltage

drop may not be acceptable from the noise point of view. If your application doesn't have audio

interface but only uses the data feature of the Telit GM862-QUAD, then this noise is not so

disturbing and power supply layout design can be more forgiving.

• The PCB traces to the GM862-QUAD and the Bypass capacitor must be wide enough to ensure

no voltage drops occur when the 2A current peaks are absorbed. This is for the same reason as

previous point. Try to keep this trace as short as possible.

• The PCB traces connecting the Switching output to the inductor and the switching diode must

be kept as short as possible by placing the inductor and the diode very close to the power

switching IC (only for switching power supply). This is done in order to reduce the radiated

field (noise) at the switching frequency (100-500 kHz usually).

• The use of a good common ground plane is suggested.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

• The placement of the power supply on the board should be done in such a way to guarantee that

the high current return paths in the ground plane are not overlapped to any noise sensitive

circuitry as the microphone amplifier/buffer or earphone amplifier.

• The power supply input cables should be kept separate from noise sensitive lines such as

microphone/earphone cables.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

4 Serial Port

The serial port on the Telit GM862-QUAD is the core of the interface between the module and

OEM hardware. Several configurations can be designed for the serial port on the OEM hardware,

but the most common are:

- RS232 PC com port

- microcontroller UART @ 2.8V - 3V (Universal Asynchronous Receive Transmit)

- microcontroller UART@ 5V or other voltages different from 2.8V

Depending from the type of serial port on the OEM hardware a level translator circuit may be

needed to make the system work. The only configuration that doesn't need a level translation is the

2.8V UART.

The serial port on the GM862-QUAD is a +2.8V UART with all the 7 RS232 signals. It differs

from the PC-RS232 in the signal polarity (RS232 is reversed) and levels. The levels for the GM862-

QUAD UART are the CMOS levels:

Absolute Maximum Ratings -Not Functional

Parameter Min Max

Input level on any

digital pin when on

-0.3V +3.75V

Input voltage on

analog pins when on

-0.3V +3.0 V

Operating Range - Interface levels (2.8V CMOS)

Level Min Max

Input high level VIH 2.1V 3.3V

Input low level VIL 0V 0.5V

Output high level VOH 2.2V 3.0V

Output low level VOL 0V 0.35V

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

The signals of the GM862-QUAD serial port are:

RS232

Number

Signal GM862-

QUAD

Number

Name Usage

1 DCD -

dcd_uart

36 Data Carrier Detect Output from the GM862-QUAD that

indicates the carrier presence

2 RXD -

tx_uart

37 Transmit line *see Note Output transmit line of GM862-QUAD

UART

3 TXD -

rx_uart

20 Receive line *see Note Input receive of the GM862-QUAD

UART

4 DTR -

dtr_uart

43 Data Terminal Ready Input to the GM862-QUAD that controls

the DTE READY condition

5 GND 2-4-6-8 Ground ground

6 DSR -

dsr_uart

33 Data Set Ready Output from the GM862-QUAD that

indicates the module is ready

7 RTS -

rts_uart

45 Request to Send Input to the GM862-QUAD that controls

the Hardware flow control

8 CTS -

cts_uart

29 Clear to Send Output from the GM862-QUAD that

controls the Hardware flow control

9 RI -

ri_uart

30 Ring Indicator Output from the GM862-QUAD that

indicates the incoming call condition

NOTE: According to V.24, RX/TX signal names are referred to the application side, therefore on the

GM862-QUAD side these signal are on the opposite direction: TXD on the application side will be

connected to the receive line (here named TXD/ rx_uart ) of the GM862-QUAD serial port and viceversa

for RX.

TIP: For a minimum implementation, only the TXD and RXD lines can be connected, the other lines can

be left open provided a software flow control is implemented.

The signals in the UART connector on the EVK are:

DCD RXD

TXD DTR

GND DSR

RTS CTS

RI GND

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

4.1 RS232 level translation

In order to interface the Telit GM862-QUAD 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. GM862-QUAD

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.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

An example of level translation circuitry of this kind is:

the RS232 serial port lines are usually connected to a DB9 connector with the following layout:

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

4.2 5V UART level translation

If the OEM application uses a microcontroller with a serial port (UART) that works at a voltage

different from 2.8 - 3V, then a circuitry has to be provided to adapt the different levels of the two

set of signals. As for the RS232 translation there are a multitude of single chip translators, but since

the translation requires very few components, then also a discrete design can be suited. For example

a possible inexpensive translator circuit for a 5V driver can be:

and for a 5V receiver:

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

NOTE: The UART input line TXD (rx_uart) of the GM862-QUAD is NOT internally pulled up with a

resistor, so there may be the need to place an external 47KΩ pull-up resistor, either the DTR (dtr_uart)

and RTS (rts_uart) input lines are not pulled up internally, so an external pull-up resistor of 47KΩ may

be required.

A power source of the internal interface voltage corresponding to the 2.8VCMOS high level is

available at the PWRCTL pin on the connector, whose absolute maximum output current is 10mA.

A maximum of 9 47 KΩ pull-up resistors can be connected to the PWRCTL pin, provided no other

devices are connected to it and the pulled-up lines are GM862-QUAD input lines connected to

open collector outputs in order to avoid latch-up problems on the GM862-QUAD.

Care must be taken to avoid latch-up on the GM862-QUAD and the use of this output line to power

electronic devices shall be avoided, especially for devices that generate spikes and noise such as

level translators, digital ICs or microcontrollers, failure in any of these condition can severely

compromise the GM862-QUAD functionality.

NOTE: The input lines working at 2.8VCMOS can be pulled-up with 47KΩ resistors that can be

connected directly to the PWRCTL line provided they are connected as in this example.

NO OTHER devices should be powered with the PWRCTL line, otherwise the module functionality may

be compromised.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

5 Microphone

The microphone circuitry is the more noise sensitive and its design and layout must be done with

particular care.

5.1 Microphone line Characteristic and

requirements

The Telit GM862-QUAD provides two audio paths for the microphone and the earpiece: the

internal and the external audio paths. Only one of the two paths can be active at a time and it is

selectable by hardware line AXE or by AT command. The audio characteristics of the two paths are

slightly different and this should be kept in mind when designing. The internal audio path should be

used for handset function, while the external audio path is suited for hands free function (car kit).

Both microphone paths from the Telit GM862-QUAD are balanced and the OEM circuitry should

be designed balanced to reduce the common mode noise typically generated on the ground plane,

however for particular OEM application needs also an unbalanced circuitry can be used.

The microphone input lines characteristics are:

internal microphone path

• line coupling: AC ( 100nF cond.)

• line type: balanced

• differential input resistance: 25kΩ

• line nominal sensitivity: 50 mVrms

• max input voltage: 360 mVrms

• microphone nominal sensitivity/analog gain suggested: -45 dBVrms/Pa / +24dB

• echo canceller type: handset

external microphone path

• line coupling: AC ( 100nF cond.)

• line type: balanced

• differential input resistance: 25kΩ

• line nominal sensitivity: 3 mVrms

• max input voltage: 22 mVrms

• microphone nominal sensitivity/analog gain suggested: -45 dBVrms/Pa / +10dB

• echo canceller type: car kit hands free

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

TIP: Due to the difference in the echo canceller type, the internal audio path is suited for handset

applications while the external audio path is suited for car kit hands free. The headset applications

should be made by using the external audio path but DISABLING the echo canceller by software AT

command. If the echo canceller is left active with the headset, then some echo might be introduced by

the echo cancel algorithm.

The nominal sensitivity of the line indicates the voltage level on the GM862-QUAD pins that

should be present during "normal spoken" conditions: for a handset a voice signal coming from the

mouth of the talker at 7 cm of distance from the microphone, producing an acoustic pressure of -4,7

dBPa (@ 1 kHz) on the microphone membrane.

For example:

With the internal mic. having the suggested nominal sensitivity -45dBVrms/Pa

at the "normal spoken" conditions: -4.7dB Pa on the microphone membrane.

At that acoustic pressure the voltage output from the microphone is:

Voltage Output (dB) = ( -45) + (-4.7) = -49.7 dBVrms

corresponding to:

Voltage Output = 10 ( -49.7 / 20 ) = 3.3* 10 -3 Vrms

by having the microphone gain set to +24 dB (corresponding to 15.8 times) the signal in the

nominal conditions on the input mic. pins of the GM862-QUAD will be:

Voltage @ GM862-QUAD_mic = 3.3 * 10 -3 * 15.8 = 51 mVrms

During the spoken conditions the signal varies according to the volume of the voice of the talker,

usually a rough thumb rule for the dynamic range may be considered:

* +20dB (10 times) at maximum voice level (talker screaming)

* -50 dB (1/300 times) at minimum voice level (talker whispering).

For the handsfree/car kit microphone the voice attenuation due to the distance between the

microphone and the talker must be taken into account when designing the microphone amplifier.

For a car cabin usually the distance between the talker and the mic. is about 50cm; in these

conditions the attenuation can be considered as a thumb rule around 20dB.

Another thing to consider, especially for cabin car use, is the fact that the external mic. will pick up

also ambient noise; to overcome this problem it is preferable to set the gain of the microphone 10dB

lower with respect to the calculated value for a nominal sensitivity. The corresponding reduction in

signal level will be compensated by an increased voice volume of the talker which will speak louder

because of the ambient noise.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

For the headset we shall distinguish two different types: the headsets having the microphone

sustained close to the mouth and the headsets having the microphone on the earpiece cable.

The same considerations for the additional voice attenuation due to the distance from the

microphone and the noise pick up can be made for the headset having the microphone on the

earpiece cable, while the other kind of headset shall be threaten as an handset.

For example:

With the external mic. having the suggested nominal sensitivity -45dBVrms/Pa

at the "normal spoken" conditions: -4.7dB Pa at 7 cm from the mouth of the talker and with a

further attenuation of 20dB due to the distance from the microphone (about 50 cm).

At that acoustic pressure the voltage output from the microphone is:

Voltage Output (dB) = ( -45) + (-4.7) - 20 = -69.7 dBVrms

corresponding to:

Voltage Output = 10 ( -69.7 / 20 ) = 3.3* 10 -4 Vrms

by having the microphone gain set to +10 dB (corresponding to 3 times) the signal in the nominal

conditions on the input external mic. pins of the GM862-QUAD will be:

Voltage @ GM862-QUAD__extmic = 3.3 * 10 -4 * 3 = 1 mVrms

Hence in these conditions the signal level on the input pins of the external mic. of the GM862-

QUAD is 10 dB (3 times) lower than the nominal, as suggested.

The microphones usually need a biasing network that provides the necessary DC current to the mic.,

this will be explained further on.

In the EVK all the microphone input jacks have the hot wire connected to the central pole.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

5.2 General Design Rules

There are several configurations for the audio path, but the most effective difference is between

balanced and unbalanced microphone.

It is highly recommended to keep the whole microphone path balanced even if this means having 2

wires connecting the microphone instead of one needed (plus ground) in the unbalanced case. The

balanced circuitry is more suited because of its good common mode noise rejection, reducing the

216 Hz burst noise produced during the GSM transmissions.

• Where possible use balanced microphone circuitry

• Keep the microphone traces on the PCB and wires as short as possible.

• If your application requires an unbalanced microphone, then keep the lines on the PCB

balanced and "unbalance" the path close to the microphone wire connector if possible.

• For the microphone biasing voltage use a dedicated voltage regulator and a capacitor multiply

circuit.

• Make sure that the microphone traces in the PCB don't cross or run parallel to noisy traces

(especially the power line)

• If possible put all around to the microphone lines a ground trace connected to the ground plane

by several vias. This is done in order to simulate a shielded trace on the PCB.

• The biasing circuit and eventually the buffer can be designed in the same manner for the

internal and external microphones.

5.3 Microphone Biasing

The electret microphones usually need a biasing voltage to work properly. Refer to your

microphone provider for the characteristics required.

NOTE: The microphones have a hot wire were the positive biasing must be connected, usually it is

indicated by a + sign or a red point. If the polarity of the bias is reversed, then the microphone will not

work properly. For this reason be sure to respect the mic. biasing polarity.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

5.3.1 Balanced Microphone biasing

The balanced microphone bias voltage should be obtained from a dedicated voltage regulator, in

order to eliminate the noise present on the power lines. This regulator can be the same for all the

audio paths. The microphone should be supplied from a capacitor multiply circuit.

For example a circuit for the balanced microphone biasing can be:

NOTE: In the balanced application the resistors R2 and R3 must have the same value to keep the

circuit balanced.

NOTE: The cable to the microphone should not be shielded, instead a twisted pair cable shall be used.

NOTE: The microphone sensitivity changes with the value of R2 and R3. Usually the microphones are

characterized with 2kΩ biasing resistance, so try to keep the sum of R2 and R3 around 2kΩ. Refer to

your microphone manufacturer for the mic. characteristics.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

5.3.2 Unbalanced Microphone biasing

The unbalanced microphone biasing voltage should be obtained from a dedicated voltage regulator,

in order to eliminate the noise present on the power lines. This regulator can be the same for all the

audio paths. The microphone should be supplied from a capacitor multiply circuit.

For example a circuit for the unbalanced microphone biasing can be:

NOTE: In the unbalanced application the capacitor C3 shall be > 200nF otherwise the frequency

response will be cut at low band frequencies (down to 300Hz). This capacitor can be placed close to

the MIC- pin (EXT_MIC- or INT_MIC- depending on the audio path chosen) or if possible it should be

placed close to the shielded cable connector. If the ground return path is well designed, then it is

possible to eliminate the C3 capacitor, provided the buffer is close to the mic. input.

NOTE: The cable to the microphone should be shielded.

NOTE: The microphone sensitivity changes with the value of R2. Usually the microphones are

characterized with 2kΩ biasing resistance, so try to keep the value of R2 around 2kΩ. For mic.

characteristics refer to the manufacturer.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

5.4 Microphone buffering

As seen previously, a microphone shall be connected to the input pins of the GM862-QUAD

through a buffer amplifier that boosts the signal level to the required value.

Again the buffered microphone circuitry can be balanced or unbalanced. Where possible it is

always preferable a balanced mic. solution. The buffering circuit shall be placed close to the

microphone or close to the microphone wire connector.

5.4.1 Buffered Balanced Mic.

A sample circuit can be:

This circuit has a gain of 15 times (+24 dB), and is therefore suited for the internal mic. input,

having a microphone with a sensitivity close to the suggested one (-45 dBVrms/Pa), if the used

microphone has a different sensitivity, or if the buffer is connected to the external mic. input, then a

gain adjustment shall be done by changing resistors R604-R605 and R606-R607 and as a

consequence the capacitors C636 and C637 to maintain the bandwidth 150-8000 (-3dB).

The buffer gain is given by the formula:

607

606

605

604

Gain ==

The C636 and C637 capacitors are placed in order to cut off the gain at higher frequencies than the

transmitted GSM band, the cutoff frequency (-3dB) should be 8 kHz in order to have -1dB at 4Khz.

The cutoff frequency is given by the formula:

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

636*606*2

637*604*2

.CRCR

freq

ππ

== [Hz]

For example:

- Let's assume you have a microphone with these characteristics:

- sensitivity -45 dBVrms/Pa

and you want to use it in the internal mic. audio path.

With the mic. having nominal sensitivity -45dBVrms/Pa at the "normal spoken" conditions: -4.7dB Pa

at 7 cm from the mouth of the talker.

At that acoustic pressure the voltage output from the microphone is:

Mic Voltage Output (dB) = ( -45) + (-4.7) = -49.7 dBVrms

corresponding to:

Mic_Voltage_Output = 10 ( -49.7 / 20 ) = 3.3* 10 -3 Vrms

in order to have a signal of 50 mVrms on the GM862-QUAD internal mic. inputs then the buffer must

have a gain of:

Voltage @ GM862-QUAD_intmic/ Mic_Voltage_Output = (50 * 10 -3 )/( 3.3 * 10 -3 ) = 15

Hence in these conditions the signal level on the input pins of the internal mic. of the GM862-

QUAD is 24 dB (15 times) higher than the microphone output and therefore the buffer has to gain

24 dB.

The corresponding values for the resistors on the buffer could be ( if we keep the input resistance

10kΩ )

R604 = R606 = gain* R603= gain* R605 = 15* 10 = 150 kΩ

The commercial values of 150kΩ & 10kΩ are then chosen.

As a consequence the values of the capacitors C636 and C637 shall be:

C636=C637= 1/ (2π*8000*R606)= 132 *10 -12 F

A commercial value of 100pF is then chosen.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

5.4.2 Buffered Unbalanced (Single Ended) Mic.

A sample schematic for a buffered unbalanced (single ended) microphone can be:

The schematic does not include the required mic. biasing circuitry. For the biasing the same circuit

as seen before can be used; to be noticed that the capacitor C3 on the unbalanced biasing circuit is

not anymore needed if this Buffered design is used.

Two different configurations are used, one inverting and the other not inverting, hence an additional

+6dB (2 times) gain is achieved by doubling the mic. signal path.

The gain of the not inverting buffer is given by the formula:

720

719

Gain +=

and hence it cannot be less than 1. In the example shown the gain of the not inverting buffer is 1,5

(4dB).

While the gain of the inverting buffer is given by the formula:

708

711

Gain =

As shown in the balanced buffered mic. the gain adjustments can be done by changing R719 - R720

and R708 - R711 and as a consequence the capacitors C726 and C727.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

The bandwidth (-3dB) is given by the approximated formula (considering C725 >> C726) :

727*711*2

726*719*2

.CRCR

freq

ππ

== [Hz]

The buffer bandwidth at -3dB shall be 8kHz.

Note that the biasing of the operational amplifier is given for the inverting amplifier by the series

divider R714-R715. The 100nF capacitor C719 is needed to filter the noise that could be coupled to

that divider. For the not inverting operational the biasing is given by a different divider R715-R717

with the capacitor C720 and through a series resistor R718 of 470KΩ.

For example:

- Let's assume you have a microphone with these characteristics:

- sensitivity -45 dBVrms/Pa

and you want to use it in the external mic. audio path.

With the mic. having nominal sensitivity -45dBVrms/Pa at the "normal spoken" conditions: -4.7dB Pa

but at 50 cm from the mouth of the talker an additional 20 dB loss shall be considered.

At that acoustic pressure the voltage output from the microphone is:

Mic Voltage Output (dB) = ( -45) + (-4.7) -20 = -69.7 dBVrms

corresponding to:

Mic_Voltage_Output = 10 ( -69.7 / 20 ) = 3.3* 10 -4 Vrms

in order to have a signal of 1 mVrms (10 dB lower than the nominal input for the GM862-QUAD

external mic. path) on the GM862-QUAD internal mic. inputs then the buffer must have a gain of:

Voltage @ GM862-QUAD_intmic/ Mic_Voltage_Output = (1 * 10 -3 )/( 3.3 * 10 -4 ) = 3

Hence in these conditions the signal level on the input pins of the internal mic. of the GM862-

QUAD is 10 dB (3 times) higher than the microphone output and therefore the buffer has to gain 10

dB.

To calculate the resistor values it must be kept in mind that balancing the line will double the signal

and hence already add +6 dB, therefore the buffer must gain only 1.5 times.

The corresponding values for the resistors on the buffer could be ( if we keep the input resistance

10kΩ )

R711 = gain* R708= 1.5* 10 = 15 kΩ

R719 = (gain -1) * R720 = (1.5 -1) * 10 = 5 kΩ

The commercial values of 15kΩ & 5.6kΩ are then chosen.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

As a consequence the values of the capacitors C726 and C727 shall be:

C726= 1/ (2π*8000*R719)= 3.5 *10 -9 F

C727= 1/ (2π*8000*R711)= 1,2 *10 -9 F

The commercial values of 3.3nF and 1nF are then chosen.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

6 Speaker

6.1 Speaker lines characteristics and requirements

The Telit GM862-QUAD provides two audio paths for both the microphone and the earpiece: the

internal and the external audio paths. Only one of the two paths can be active at a time and it is

selectable by hardware line AXE or by AT command. The audio characteristics of the two paths are

slightly different and this should be kept in mind when designing your application. The internal

audio path should be used for handset function, while the external audio path is suited for hands free

function (car kit).

Both speaker outputs from the Telit GM862-QUAD are bridged type and the OEM circuitry shall

be designed bridged to reduce the common mode noise typically generated on the ground plane and

to get the maximum power output from the device; however for particular OEM application needs

also a single ended circuitry can be designed.

The GM862-QUAD speaker output lines characteristics are:

internal speaker path ( EAR_MT+ , EAR_MT- )

• line coupling: DC

• line type: bridged

• speaker impedance (operating conditions): ≥ 16 Ω ± 5% @ 1kHz

• minimum load impedance: 15 Ω

• signal bandwidth: 150 - 8000 Hz @ -3 dB

• maximum differential output: 850 mVrms

• rated output power: 10 mW

• maximum power output: 30 mW

• volume level steps (SW): - 2 dB

• number of volume steps(SW): 10

external speaker path ( EAR_HF+ , EAR_HF- )

• line coupling: DC

• line type: bridged

• speaker impedance (operating conditions): ≥ 16 Ω ± 15% @ 1kHz

• minimum load impedance: 15 Ω

• signal bandwidth: 150 - 8000 Hz @ -3 dB

• maximum differential output: 425 mVrms

• rated output power: 2.5 mW

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

• maximum power output: 7.5 mW

• volume level steps (SW): - 2 dB

• number of volume steps (SW): 10

The EVK v.1.2 audio output characteristics are:

internal/external ear single ended

• line coupling: AC

• line type: single ended referred to GND

• speaker impedance (operating conditions): ≥ 8 Ω

• minimum load impedance: 8 Ω

• signal bandwidth: 150 - 8000 Hz @ -3 dB

• maximum output: 800 mVrms

• maximum power output: 80 mW @ 8 Ω

• THD+N 1% @ 80mW

internal/external ear bridged

• line coupling: DC

• line type: bridged not referred to GND

• speaker impedance (operating conditions): ≥ 8 Ω

• minimum load impedance: 8 Ω

• signal bandwidth: 150 - 8000 Hz @ -3 dB

• maximum output: 1.6 Vrms

• maximum power output: 320 mW @ 8 Ω

• THD+N 1% @ 330mW

high power external ear

• line coupling: DC

• line type: bridged not referred to GND

• speaker impedance (operating conditions): ≥ 4 Ω

• minimum load impedance: 4 Ω

• signal bandwidth: 150 - 8000 Hz @ -3 dB

• maximum power output: 6 W

• THD+N 10% @ 6 W

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

6.2 General Design rules

There are several configurations for the audio output path, but the various design requirements can

be grouped into three different categories:

• handset earphone (low power, typically a handset)

• hands free earphone (low power, typically a headset)

• car kit speakerphone (high power, typically a speaker)

The three groups have different power requirements, usually the first two applications need only

few mW of power, which can be directly drained from the GM862-QUAD pins, provided a suited

speaker is used. This direct connect design is the cheaper and simpler solution and will be suited for

the most of the earphone design requirements. There's no need to decouple the output ear lines if a

suited earpiece is connected. For the last group, the speakerphone, a power amplifier is required to

raise the output power up to 5-10W required in a car cabin application.

All the designs shall comply with the following guidelines:

• Where possible use a bridged earphone circuitry, to achieve the maximum power output from

the device.

• Keep the earphone traces on the PCB and wires as short as possible.

• If your application requires a single ended earpiece and you want a direct connection, then

leave one of the two output lines open and use only the other referred to ground. Remember

that in this case the power output is 4 times lower than the bridged circuit and may not be

enough to ensure a good voice volume.

• Make sure that the earphone traces in the PCB don't cross or run parallel to noisy traces

(especially the power line)

• The cable to the speaker shall be a twisted pair with both the lines floating for the bridged

output type, shielded with the shield to ground for the single ended output type.

6.2.1 Noise Filtering

The I/O of the PCB should have a noise filter close to the connector, to filter the high frequency

GSM noise. The filter can be a Π of 2 capacitor and a inductance, with the one capacitor of 39pF -

0603 case , and the other capacitor of 1nF - 0603; the inductance shall have a value of 39μH .

6.3 Handset earphone design

As seen previously, a 16Ω speaker can be directly connected to the output pins EAR_MT+ and

EAR_MT- of the GM862-QUAD.

This solution is often the more cost effective, reducing the components count to a minimum. There

are several limitations to the use of this solution: speaker direct connect imposes the speaker

characteristics to be almost exactly the suggested ones, otherwise the power output may be reduced

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

(if speaker impedance is bigger than 16Ω) or the GM862-QUAD ear port may be damaged (if

speaker impedance is less than 15Ω).

The other limitation of the speaker direct connection is the power output capability of the GM862-

QUAD which is limited and for some particular applications may not be enough.

For these reasons, when the power output of the GM862-QUAD is not enough or if the speaker

characteristics are different from the suggested, then it is preferable to use an amplifier to increase

the power and current output capabilities.

Again the output from the GM862-QUAD is bridged and both lines should be used, where possible,

as inputs to the power amplifier. This ensures a higher common mode rejection ratio, reducing the

GSM current busts noise on the speaker output.

In this case the EAR_MT lines from the GM862-QUAD should be AC coupled with a capacitor of

100nF.

It is always desirable to have a mute control on the amplifier, in order to turn it off while the device

is not sending signal to the output, in this manner the amplifier background noise which may be

audible during idle conditions is cut off.

A principle schematic may be:

The resulting gain and high pass cut can be obtained with the formula:

Gain =

4*3*2

.CR

freq

= [Hz]

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

And an example of internal Ear amplifier is:

Some amplifier require a low impedance load at high frequency in order to avoid auto oscillation,

this can be made with a capacitor (100nF) in series with a resistor (15Ω).

When designing your application, remember to provide an adequate bypass capacitor to the

amplifier and place it close to the power input pin of the IC, keeping the traces as short as possible.

6.4 Hands Free earphone (low power) design

The same design considerations made for the handset are valid for the hands free earphone, the only

difference is that the external ear audio output level from the GM862-QUAD is 6dB lower than the

internal one, so the gain of the amplifier must be 6dB higher to provide the same audio level.

6.5 Car Kit speakerphone design

For the car kit speaker phone function the power output requirement is usually at least 4W,

therefore an amplifier is needed to boost the GM862-QUAD output.

The design of the amplifier shall comply with the following guidelines:

• The input to the amplifier MUST be taken from the external audio path (EAR_HF+, EAR_HF-)

of the GM862-QUAD, because of its echo canceller parameters suited to a car cabin use.

• The amplifier shall have a gain of 30-40 times ( 29-32 dB) to provide the desired output power

of 5-10W with the signal from the GM862-QUAD external audio output lines (EAR_HF).

• If the amplifier has a fixed gain then it can be adjusted to the desired value by reducing the input

signal with a resistor divider network.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

• The amplifier shall have a mute control to be used while not in conversation. This results in two

benefits: eliminating the background noise when not in conversation and saving power.

• The power to the amplifier should be decoupled as much as possible from the GM862-QUAD

power supply, by either keeping separate wires and placing bypass capacitors of adequate value

close to the amplifier power input pins.

• The biasing voltage of the amplifier shall be stabilised with a low ESR (e.g. a tantalum)

capacitor of adequate value.

NOTE: The GM862-QUAD audio path connected to the car kit hands free amplifier MUST be the

external one (EAR_HF), otherwise the echo cancellation will not be done due to the difference in the

echo canceller characteristics of the GM862-QUAD internal audio path from the external audio path.

An example of car kit amplifier schematic can be:

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

7 General Purpose I/O

The general purpose I/O pins can be configured to act in three different ways:

- input

- output

- alternate function (internally controlled)

Input pins can only be read and report the digital value (high or low) present on the pin at the read

time; output pins can only be written or queried and set the value of the pin output; an alternate

function pin is internally controlled by the GM862-QUAD firmware and acts depending on the

function implemented.

Not all GPIO pins support all these three modes:

- GPIO1 is an INPUT ONLY

- GPIO2 is an OUTPUT ONLY (open collector)

- GPIO3, GPIO4 and GPIO5 support both input or output mode but not Alternate function.

- GPIO6 supports all three modes and can be input, output, alarm output (Alternate function)

- GPIO7 supports all three modes and can be input, output, buzzer output (Alternate function)

All GPIO pins except from GPIO1 and GPIO2 that are buffered with a transistor, are 2.8V CMOS

signals and their interface levels are the same specified in the paragraph 4 Serial Port.

7.1 Using a GPIO pin as INPUT

The GPIO pins, when used as inputs, can be connected to a digital output of another device and

report its status, provided this device has interface levels compatible with the 2.8V CMOS levels of

the GPIO.

If the digital output of the device to be connected with the GPIO input pin has interface levels

different from the 2.8V CMOS, then it can be connected to GPIO1 or can be buffered with an open

collector transistor, provided a 47KΩ pull-up resistor is connected as seen in the paragraph 4.2 5V

UART level translation.

7.2 Using a GPIO pin as OUTPUT

The GPIO pins, when used as outputs, can drive 2.8V CMOS digital devices or compatible

hardware. When set as outputs, the pins (except from GPIO2 which is Open Collector) have a push-

pull output and therefore the pull-up resistor may be omitted.

The GPIO2 pin, since it is an Open Collector output needs an external pull-up resistor.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

7.3 Using the Alarm Output GPIO6

The GPIO6 pin, when configured as Alarm Output, is controlled by the GM862-QUAD module and

will rise when the alarm starts and fall after the issue of a dedicated AT command.

This output can be used to power up the GM862-QUAD controlling microcontroller or application

at the alarm time, giving you the possibility to program a timely system wake-up to achieve some

periodic actions and completely turn off either the application and the GM862-QUAD during sleep

periods, drammatically reducing the sleep comsumption to few μA.

In battery powered devices this feature will greatly improve the autonomy of the device.

7.4 Using the Buzzer Output GPIO7

The GPIO7 pin, when configured as Buzzer Output, is controlled by the GM862-QUAD module

and will drive with appropriate square waves a Buzzer driver.

This permits to your application to easily implement Buzzer feature with ringing tones or melody

played at the call incoming, tone playing on SMS incoming or simply playing a tone or melody

when needed by your application.

A sample interface scheme is included below to give you an idea of how to interface a Buzzer to the

GPIO7:

NOTE: To correctly drive a buzzer a driver must be provided, its characteristics depend on the Buzzer

and for them refer to your buzzer vendor.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

8 Camera

8.1 Agilent Camera

The GM862-QUAD provides a direct support for digital cameras with the following characteristics:

Type: AGILENT ADCM2650

Technology: CMOS COLOR camera

Max picture size: VGA 640x480 pixels

Output format: JPEG

Sensitivity: 5 lux

8.1.1 Camera interface connectors

The interface connection between GM862-QUAD and camera is provided by the 50-pins Molex

connector of the module and a 18-pins ZIF connector vertical type for the CMOS camera.

Molex 52991-0508 GM862 ZIF CF21181V0RP

Pin Signal I/O Function Pin Signal I/O

21 CAM_SYNC I End of frame is an output for the

camera and an input for the GM862-

QUAD.

16 EOF O

25 MON1_CAM O The module clock is provided by the

MON1_CAM output of the GM862-

QUAD.

17 MCLK I

28 IICSCL_CAM O IICbus serial clock 4 S_CLK I

32 PD(0) I/O Parallel Data 0 15 DATA0 I/O

34 PD(1) I/O Parallel Data 1 14 DATA1 I/O

38 PD(2) I/O Parallel Data 2 13 DATA2 I/O

40 PD(3) I/O Parallel Data 3 12 DATA3 I/O

42 PD(4) I/O Parallel Data 4 11 DATA4 I/O

44 PD(5) I/O Parallel Data 5 10 DATA5 I/O

46 PD(6) I/O Parallel Data 6 9 DATA6 I/O

49 PD(7) I/O Parallel Data 7 8 DATA7 I/O

47 IICSDA_CAM I/O IICbus serial data 3 S_DATA I/O

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

48 CAM_DRDY I Data ready in an output for the camera

and an input for the GM862-QUAD

7 DR O

50 CAM_PWR_ON O 2,8V power supply enable for the

camera

2 VCC_MAIN I

Horizontal sync n.c. 6 HSYNC O

Input command for switching power

ON or OFF

5 ON_OFF I

2-4-

GND Ground 1-

GND

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

NOTE: GM862-QUAD is 100% pin-to-pin compatible with previous GM862 models. Therefore, in order

to connect the camera to the standard 50-pins Molex industrial connector, some pins will have dual-

function (GPIO pins, except for GPIO1): as usual GPIO operations or CAMERA support. See Molex PIN-

OUT described in the GM862-QUAD Product description.

NOTE: The CMOS camera must be removed when the GPIO pins are used for I/O purpose.

NOTE: The white point on the ADCM2650 camera cable have to match with pin18 on ZIF connector.

8.1.2 EVB for camera support

In order to interface the Telit GM862-QUAD with a CMOS camera, Telit has developed an

evaluation board. The EVB is provided by:

• 10 pin Berg male connector (PL201) and RS232 level translator that allows a direct connection

to the PC. To switch on the level translator a jumper shall be set on PL203.

• 12 pin Berg male connector (PL202) to supply the GM862-QUAD mounted on the EVB. The

input source power should be in the range 4,5V-12V. Charge line is also provided in case a Li-

Ion battery is connected to the VBATT pins. Charge input must fulfil charger line requests.

• 50 pin Molex male connector (PL103) to interface with the GM862-QUAD directly.

• 30 pin Berg male connector (PL101) to interface with a PCB developed by the user or the EVK

board. On this connector is available the complete audio path, the serial port lines with full

handshaking, and the pins ON, AXE, RESET, GPIO1 and STAT_LED. Also the

CHARGER_IN pin can be available placing a 0 ohm resistor.

• 18 pin ZIF female connector (SO101) for CMOS camera.

• ON/OFF button (SW102) to power on and off the module.

• GPIO1 button (SW101) for future applications.

• Led (DL101) for device status indication.

NOTE: The Philips 74LVC1G08GW must be placed close to the GM862 connector; the length of the line

between CAMERA connector and MOLEX 50 PIN of GM862 must be max 5cm anyway.

NOTE: The CMOS cameras must be removed when the GPIO pins are used for I/O purpose.

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

8.2 Camera Transchip

The GM862-QUAD provides a direct support for Transchip digital cameras with the following

characteristics:

8.2.1Camera interface connectors

The 50-pins Molex connector of the module and a 24 pins ZIF connector for the CMOS camera

provide the interface connection between GM862 and Transchip camera.

Molex 52991-0508 GM862 TC5747MF24L

Pin Signal I/O Notes Pin Signal I/O

46 GPIO3

PD(6)

O I2C bus serial clock 1 SCLK I

2-4-6 GND Ground 2 AGND I

50 GPIO7

CAM_PWR_ON

O External 2.8V Regulator enable

controlled by CAM_PWR_ON pin

3 AVDD28* I

34 GPIO9

PD(1)

O Camera Reset 4 RESET_N I

25 MON1

MON1_CAM

O Clock 5 CLK_IN** I

2-4-6 GND Ground 6 DGND I

n.c 7 DOUT_0 I/O

n.c 8 DOUT_1 I/O

n.c 9 DOUT_2 I/O

n.c 10 DOUT_3 I/O

n.c 11 DOUT_4 I/O

n.c 12 DOUT_5 I/O

n.c 13 DOUT_6 I/O

n.c 14 DOUT_7 I/O

n.c 15 DOUT_8 I/O

Type: TRANSCHIP TC5747

Technology: CMOS COLOR camera

Max picture size: VGA 480x640 pixels landscape

Output format: JPEG

Sensitivity: 4 Lux

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

n.c 16 VCLKOUT O

n.c 17 VALIDH O

n.c 18 VALIDV O

50 GPIO7

CAM_PWR_ON

O External 2.8V Regulator enable

controlled by CAM_PWR_ON pin

19 DVDD28 I

47 GPIO4

IICSDA_CAM

I/O I2C bus serial data 20 SDIN I/O

2-4-6 GND Ground 21 PS1 I

32 GPIO8

PD(0)

O Camera power type selector 22 PS2 I

2-4-6 GND Ground 23 SHIELD -

Flash Enable 24 LED_CTRL O

* Filter the AVDD28.

** Use a Buffer between module clk out, MON1_CAM and camera clk in, CLK_IN.

*** Non-connected.

Camera Socket Connector

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

8.2.2EVB for Agilent and Transchip camera support

In order to interface the Telit GM862 with a CMOS camera, Telit has developed an evaluation

board. The EVK allow connecting all Telit modules through 2 connectors of 40 pins each.

The I2CBUS DUAL CAMERA board is plugged in the 2 connectors of 30 pins each on the module

board.

MODULE

BOARD

MAIN

BOARD

CAMERA

BOARD

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

8.2.3Block Diagram for supported cameras

The numbers on the left side of the Camera’s connectors refers to Module Connector’s pin number.

DVDD is an external power supply of 2.8V, controlled or gated by pin CAM_PWR_ON.

GND

DVDD

IICSDA_CAM

IICSCL_CAM

CAM_PWR_ON

CAM_DRDY

PD[7]

CAM_SYNC

CAM_CLK

GND

PD[6]

PD[5]

PD[4]

PD[3]

PD[2]

PD[1]

PD[0]

GND

AVDD

CAM_CLK

GND

DVDD

IICSDA_CAM

GND

PD[1]

PD[0]

PD[6]

CAM_CLK

DVDD AVDD

GND

CAMERA AGILENT CAMERA TRANSCHIP

MON1_CAM

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

8.2.4 Schematic Diagrams for supported cameras

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

8.2.5Example usage script for camera

Camera setting: (shown here are the defaults ones)

>AT#CAMSEL=0 (camera selection: 0-auto, 1-agilent, 2-transchip)

>AT#CMODE=0 (camera mode: 0-day, 1-night)

>AT#CAMQUA=0 (camera quality: 0-low, 1-medieum, 2-high)

>AT#CAMRES=0 (camera resolution: 0-VGA, 1-QVGA, 2-QQVGA)

>AT#CAMCOL=0* (camera color: 0-color, 1-grayscale)

>AT#CAMZOOM=0 (camera zoom: 0-x1, 1-x2, 2-x4)

>AT#CAMTXT=0* (camera timestamp: 0-no, 1-time only, 2-data only, 3-time&data)

Taking an reading a photo:

>AT#CAMEN=1 (camera ON)

>AT#TPHOTO (take photo)

>AT+OBJL? (see photo dimension)

#OBJL: Snapshot,38900 (where 38900 is the file dimension in bytes of the photo taken)

>AT#RPHOTO (download the photo)

…data….. (where …data… Correspond to the photo data in binary)

>AT#TPHOTO

>AT#RPHOTO Repeating photo capture and download n times

…data…..

>AT#CAMEN=O (camera OFF)

*only Transchip camera

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

9 Document Change Log

Revision Date Changes

Telit GM862-QUAD/-QUAD-PY

Hardware User Guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

10 Annex A - EVK schematics

FORBIDDENVIETATE

RIPRODUZIONE E DIVULGAZIONE REPRODUCTION AND DISCLOSURE

PROJECT A3

DESCRIPTION

DRAWING CODE

FORM

MODIFY

OF SHEETS

DATE

SHEET N.

VERIFIED

PROJECT

DRAWN

PATH /home/users/area

Mod. 067 rev.0 03/01 ANNOTATION

FILE NAME

Mobile Terminals S.p.A.

42 981 0713 1165

GND

50V

0603

68nF

X7R

C104

GND

CR32

4.7

10%

R105

CR32

4.7

10%

R102

CR32

4.7

10%

R103

CR32

4.7

10%

R104

STPS340U

SMB

U34

D107

35V

CONT-A

1uF

C105

GND

2SJ387S

DPAK-2S

Q102

3S1

GND

FCMM0502

SO104

GND

FCMM0502

SO101

1215061-03F

PL101

GND

STPS140Z

SOD123

D106

+VBATT

002:11D

GND

LY-T670HK

PLCC2

YELLOW

DL101

OT101 OT102 OT103 OT104

FCMM0502

SO103

GND

0603

10K

R101

3Fs

BC857B

SOT-23

Q101 2

0603

5.6K

R106

0603

680

R107

50V

0603

4.7nF

X7R

C101

LTC1730EGN-4

U101

14 NC_14

5FAULT

GND_1

11 NTC/SHDN

10 TIMER 8

GND_8

VCC

4ACPR

GND_16

GND_9

SENSE

GATE

12 SEL

6CHRG

7NC_7

BAT

LY-T670HK

PLCC2

YELLOW

DL102

LS-T670HK

PLCC2

RED

DL103

GND

LR32

0.1

R108

50V

0603

47nF

X7R

C102

50V

0603

220pF

X7R

C103

0603

10K

R109

GND

0603

10K

R111

GND

0603

4.3K

R110

FCMM0502

SO102

0603

R112

0603

R113

0603

R114

GND

0603

R115

0603

R116

noMount=YES

041201

EVK for GM862/S1

0208

301101

Locatelli M. 1 30208SE10944b

cs944b.cir

Deperini F. BATTERY CHARGE CONTROL

ON CHARGE

NTC enabled

NTC disabled

Temperature sensing control

WARNING!!!!

When the temperature sensing is disabled

the charger must be powered ONLY if the

battery temperature is within the charging

BATTERY CHARGER INPUT +

6 Vcc

3,7V(Li-Ion) Nominal

BATTERY LI-ION

current limit: 500 mA

max voltage 4,2V (Li-Ion)

Li - Ion battery charger

max current ~ 1 A

Current Limiting Circuit

polarity is respected!

! WARNING!!!!

When using battery care must be

taken to ensure that the right

WARNING!!!!

Max current limit must be properly

set for the size of battery in use

Keep max current around 1/2 of

battery pack capacity

E.g. 1000mAh -> 500 mA max

CURRENT UNLIMITED

BATTERY CHARGER INPUT -

4.5 - 10 Vcc

CURRENT LIMITED

CHARGER PRESENCE

FAULT

Temperature sensor

10k NTC

Otherwise the battery may explode!

range 0 - 50 C.

power input is respected!

! WARNING!!!!

Care must be taken to ensure

that the right polarity in the

WARNING!!!!

For a proper battery temperature

sensing the Termistor should be

placed on the battery pack.

DO NOT Supply power when the

Battery is not connected

Otherwise GM862 may be damaged!

Curr. limit is given by R102 to R105

suggested capacity: 1000mAh

Serdi M.

FORBIDDENVIETATE

RIPRODUZIONE E DIVULGAZIONE REPRODUCTION AND DISCLOSURE

PROJECT A3

DESCRIPTION

DRAWING CODE

FORM

MODIFY

OF SHEETS

DATE

SHEET N.

VERIFIED

PROJECT

DRAWN

PATH /home/users/area

Mod. 067 rev.0 03/01 ANNOTATION

FILE NAME

Mobile Terminals S.p.A.

42 981 0713 1165

GND

STPS140Z

SOD123

D206

noMount=YES

STPS140Z

SOD123

D205

noMount=YES

+VBATT

001:9C

GND

+12V

0603

4.7K

R204

LT1374CR

U202

5VIN

4GND_1 1

VSW

2SHDN*

GND_2

SENSE

BOOST

35V

CONT-E

10uF

C206

0603

2.7K

R203

GND

0603

R202

FCMM0502

SO201

25V

0603

39nF

X7R

C203

GND

50V

0603

1.5nF

X7R

C208

DO3316

10uH

L201

GND

10V

CONT-D

100uF

C204

GND

10V

CONT-D

100uF

C201

0603

470nF

6.3V

X5R

C209

GND

25V

0603

39nF

X7R

C207

6KA24

DZ201

GND

6KA24

DZ202

35V

CONT-E

10uF

C202

STPS140Z

SOD123

D201

GND

+3.7V

FCMM0502

SO202

GND

GND GND

BAT62-02W

SCD-80

D202

LT1528CQ

U201

5V_IN

3GND 2

SENSE

V_OUT

4SHDN*

GND_1

0603

330

R201

1215061-03F

PL201

1215061-03F

PL202

100208

041201

EVK for GM862/S1

301101Deperini F.

041201

30208SE10944b

Serdi M.

cs944b.cir

+5V/+12V INPUT POWER REGULATORS

Locatelli M.

+5V INPUT

4,5V-8 Vcc

8-15,8V Vcc

+12V INPUT

power input is respected!

! WARNING!!!!

Care must be taken to ensure

that the right polarity in the +5V/+12V select

Battery/Regulator select

+5V input linear regulator

+12V input switching regulator

LQG18HN39NJ00

LQG18

39nH

L305

GND

10V

0603

220nF

X7R

C302

TX_PROG

004:6D

LQG18HN39NJ00

LQG18

39nH

L302

LQG18HN39NJ00

LQG18

39nH

L308

LQG18HN39NJ00

LQG18

39nH

L304

+3.7V

RX_PROG

004:5D

50V

0603

1nF

X7R

C307

50V

0603

1nF

X7R

C309

50V

0603

1nF

X7R

C308

LQG18HN39NJ00

LQG18

39nH

L303

LQG18HN39NJ00

LQG18

39nH

L307 LQG18HN39NJ00

LQG18

39nH

L306

10V

0603

220nF

X7R

C304

LQG18HN39NJ00

LQG18

39nH

L301

DTR

004:6D

16V

0603

100nF

X7R

C305

FORBIDDENVIETATE

RIPRODUZIONE E DIVULGAZIONE REPRODUCTION AND DISCLOSURE

PROJECT A3

DESCRIPTION

DRAWING CODE

FORM

MODIFY

OF SHEETS

DATE

SHEET N.

VERIFIED

PROJECT

DRAWN

PATH /home/users/area

Mod. 067 rev.0 03/01 ANNOTATION

FILE NAME

Mobile Terminals S.p.A.

42 981 0713 1165

50V

0603

1nF

X7R

C306

10V

0603

220nF

X7R

C303

GND

RTS

004:6D

10V

0603

220nF

X7R

C301

ICL3207CA

SSOP-24

U301

T2_IN

15 V-

T4_IN

T5_IN

20 T5_OUT

24 T4_OUT

1TR3_OUT

2T1_OUT

C2-

C2+

16 R3_IN

R1_OUT

R2_OUT

R3_OUT

3T2_OUT

C1+

C1-

T1_IN

T3_IN

11 V+

9VCC

23 R2_IN

4R1_IN

8GND_8

GND

1615061-10F

PL301

RING

004:5D

DCD

004:6D

CTS

004:5D

787200-1

SO301

GND

50V

0603

39pF

COG

C336

50V

0603

39pF

COG

C333

GND

50V

0603

39pF

COG

C335

50V

0603

39pF

COG

C337

LQG18HN39NJ00

LQG18

39nH

L312

LQG18HN39NJ00

LQG18

39nH

L313

LQG18HN39NJ00

LQG18

39nH

L314

50V

0603

39pF

COG

C331

LQG18HN39NJ00

LQG18

39nH

L315

50V

0603

39pF

COG

C330

LQG18HN39NJ00

LQG18

39nH

L316

50V

0603

39pF

COG

C321

GND

50V

0603

39pF

COG

C318

GND

DSR

004:5D

GND

50V

0603

1nF

X7R

C326

50V

0603

1nF

X7R

C311

GND

50V

0603

1nF

X7R

C310

GND

50V

0603

1nF

X7R

C329

50V

0603

39pF

COG

C317

50V

0603

39pF

COG

C332

50V

0603

1nF

X7R

C328

GND

50V

0603

39pF

COG

C320

GND

LQG18HN39NJ00

LQG18

39nH

L309

50V

0603

39pF

COG

C319

50V

0603

1nF

X7R

C322

50V

0603

1nF

X7R

C324

GND

50V

0603

1nF

X7R

C312

50V

0603

1nF

X7R

C327

GNDGND

50V

0603

1nF

X7R

C313

50V

0603

1nF

X7R

C323

GND

50V

0603

39pF

COG

C314

GND GNDGND

GND

GND GND

GND

50V

0603

1nF

X7R

C325

GND

GNDGND

GND

LQG18HN39NJ00

LQG18

39nH

L310

GND

50V

0603

39pF

COG

C334

LQG18HN39NJ00

LQG18

39nH

L311

GNDGND

GND

GND GND GND

50V

0603

39pF

COG

C316

50V

0603

39pF

COG

C315

GND

1215061-02F

PL302

30208SE10944b31 0

301101

Serdi M.

RS232 LEVEL TRANSLATOR AND UART INPUT/OUTPUT

0208

cs944b.cir

Locatelli M.

Deperini F.

041201

EVK for GM862/S1

+3.7V UART

DCD

RXD

TXD

DTR

DSR

RTS

CTS

GND

TO RS232

GND

DSR

DCD

TXD

RXD

DTR

RTS

CTS

RS232 LEVEL TRANSLATOR POWER SELECTION

4773541130470

SO402

50V

0603

100pF

COG

C402

RESET

005:9B

16V

0603

100nF

X7R

C403

START

005:3D

TX_PROG

003:10B

GND

MIC_HF+

007:11C

DTR

003:10C

STAT_LED

005:9C

GND

005:10A

GPIO1

005:7C;006:10D

AXE

005:7E

DSR

003:10B

EAR_HF-

008:10D;009:11C

MIC_MT+

006:10B

RING

003:10B

EAR_MT+

006:10E;008:10B

RTS

003:10C

50V

0603

33pF

COG

C401

RX_PROG

003:10C

CTS

003:10B

EAR_HF+

008:10D;009:11B

50V

0603

100pF

COG

C404

16V

0603

100nF

X7R

C405

GND

53748-0504

PL401

BLM21

220

L403

MIC_MT-

006:10C

EAR_MT-

006:10D;008:10B

+3.7V

BLM21

220

L404

4312-020

0.35

noMount=YES

L402

GPIO2

005:6A

MIC_HF-

007:11D

DCD

003:10B

4312-020

0.35

noMount=YES

L401

FORBIDDENVIETATE

RIPRODUZIONE E DIVULGAZIONE REPRODUCTION AND DISCLOSURE

PROJECT A3

DESCRIPTION

DRAWING CODE

FORM

MODIFY

OF SHEETS

DATE

SHEET N.

VERIFIED

PROJECT

DRAWN

PATH /home/users/area

Mod. 067 rev.0 03/01 ANNOTATION

FILE NAME

Mobile Terminals S.p.A.

42 981 0713 1165

SIM_CARD

52827-0611

SO401

6C6

5C5

7C7

8C8

RX_TRACE

010:9C

TX_TRACE

010:9B

GPIO3

005:11D

GPIO4

005:11D

GPIO5

005:11D

GPIO6

005:11D

GPIO7

005:11D

Serdi M.

GM862 & S1 CONNECTORS

041201 4

Locatelli M.

041201

0208

Deperini F.

10 30208SE10944b

EVK for GM862/S1

cs944b.cir

301101

AXE

JP105

DTR

SIMRST

GPI01

EAR_MT-

JP103

TX_PROG

TX_TRACE

SIMRST

MIC_HF-

SIMIO

EAR_HF+

RX_TRACE

SIMVCC

EAR_MT+

GPI02

DCD

MIC_MT-

START

EAR_HF-

EAR_MT-

RX_PROG

JP104

SIMCLK

SIMVCC

MIC_MT-

MIC_HF+

CTS

TEST_32KHz

GND_EXT

MIC_HF-

JP101

AXE

DSR

JP102

MIC_MT+

RTS

RING

EAR_HF-

CCIN

MIC_HF+

JP106

SIMIO

STAT_LED

CCIN

EAR_MT+MIC_HF+

EAR_MT+

GPI02

MIC_MT-

GND

AXE

DCD

DSR

EAR_MT-

CTS

+3.7V

DTR

PWR_GND

RTS

GND

RX_PROG

EAR_HF-

START

STAT_LED

RESET

MIC_HF-

TX_PROG

RING

MIC_MT+

EAR_HF+

GPI01

S1 CONNECTOR

GM862 CONNECTOR

SIMCLK

RESET

GND

0603

R508

+3.7V

0603

10K

R509

1215061-02F

PL506

GND

+3.7V

0603

22K

R510

GPIO1

004:5D;006:10D

MUTE

008:10B;008:10D;009:11C

1215061-02F

PL504

AXE

004:4D

1215061-02F

PL505

0603

560

R503

GPIO2

004:5D

0603

560

R504

LY-T670HK

PLCC2

YELLOW

DL504

GND

0603

560

R502

GND

47K

WEs

BCR148W

SOT-323

Q506

LY-T670HK

PLCC2

YELLOW

DL503

FORBIDDENVIETATE

RIPRODUZIONE E DIVULGAZIONE REPRODUCTION AND DISCLOSURE

PROJECT A3

DESCRIPTION

DRAWING CODE

FORM

MODIFY

OF SHEETS

DATE

SHEET N.

VERIFIED

PROJECT

DRAWN

PATH /home/users/area

Mod. 067 rev.0 03/01 ANNOTATION

FILE NAME

Mobile Terminals S.p.A.

42 981 0713 1165

SKHHAL

SW501

RESET

004:7D

SKHHAL

SW502

004:4D

GND

+3.7V

LY-T670HK

PLCC2

YELLOW

DL502

0603

100

R501

GND

1215061-02F

PL502

+3.7V

LY-T670HK

PLCC2

YELLOW

DL501

GND

0603

10K

R506

noMount=YES

+3.7V

STAT_LED

004:6D

+12V

+3.7V

LY-T670HK

PLCC2

YELLOW

DL505

+3.7V

0603

560

R505

START

004:6D

GND

1215061-02F

PL501

+3.7V

1215061-02F

PL503

GND

0603

R507

TP501

47K

WEs

BCR148W

SOT-323

Q502 2

47K

WEs

BCR148W

SOT-323

Q504

47K

WEs

BCR148W

SOT-323

Q503 2

47K

WEs

BCR148W

SOT-323

Q507 2

TC7S08FU

U501

TC7S08FU

U501

VCC_1

GND_1

+3.7V

GND

16V

0603

100nF

Y5V

C501

47K

WEs

BCR148W

SOT-323

Q508 2

GND

1215061-02F

PL507

LQG18HN39NJ00

LQG18

39nH

L501

50V

0603

39pF

COG

C510

GNDGND

50V

0603

1nF

X7R

C511

50V

0603

39pF

COG

C508

50V

0603

1nF

X7R

C509

LQG18HN39NJ00

LQG18

39nH

L505

GNDGND

LQG18HN39NJ00

LQG18

39nH

L504

GND

50V

0603

39pF

COG

C506

50V

0603

1nF

X7R

C507

GND

LQG18HN39NJ00

LQG18

39nH

L503

GND

50V

0603

39pF

COG

C504

50V

0603

1nF

X7R

C505

GND

LQG18HN39NJ00

LQG18

39nH

L502

GND

50V

0603

39pF

COG

C502

50V

0603

1nF

X7R

C503

GND

GPIO7

004:10E

GPIO6

004:10E

GPIO5

004:10D

GPIO3

004:10D

GPIO4

004:10D

1615061-10F

PL508

GND

0208

041201

301101Deperini F.

cs944b.cir

Locatelli M. 30208SE10944b

Serdi M. 041201

EVK for GM862/S1

AUX PINS, STATE LEDS AND ON/RESET BUTTONS

YELLOW - STAT LED

GREEN - GPIO1 LED

GREEN - GPIO2 LED

GREEN - AXE LED

EXTERNAL ACCESSORIES

RESET BUTTON

ON BUTTON

POWER ON OUTPUT

GREEN - STEREO MUTE LED

CAR STEREO MUTE OUTPUT

EXTERNAL ACCESSORIES

SENSE INPUT

EXTERNAL ACCESSORIES

GPIO1 INPUT

GPIO2 OUTPUT

MUTE CONTROL SELECT

GPIO2

MUTE CONTROL

GPIO2

CAR STEREO

GPIO (GPRS) CONNECTOR

FORBIDDENVIETATE

RIPRODUZIONE E DIVULGAZIONE REPRODUCTION AND DISCLOSURE

PROJECT A3

DESCRIPTION

DRAWING CODE

FORM

MODIFY

OF SHEETS

DATE

SHEET N.

VERIFIED

PROJECT

DRAWN

PATH /home/users/area

Mod. 067 rev.0 03/01 ANNOTATION

FILE NAME

Mobile Terminals S.p.A.

42 981 0713 1165

+3V_INT_MIC_BAL

16V

0603

100nF

Y5V

C602

GND

50V

0603

39pF

COG

C613

1615061-08F

PL602

GND

+3V_INT_MIC_BAL

50V

0603

1nF

X7R

C614

LQG18HN39NJ00

LQG18

39nH

L602

LQG18HN39NJ00

LQG18

39nH

L603

GND

1Fs

BC847BW

SOT-323

Q602 2

MIC_MT-

004:4D

EAR_MT+

004:3D;008:10B

+3V_MIC

16V

0603

100nF

Y5V

C617

0603

82K

R610

0603

10K

R611

GND

50V

0603

1nF

X7R

C616

0603

10K

R605

0603

10K

R607

GND

LQG18HN39NJ00

LQG18

39nH

L605

0603

2.2K

R608

16V

0603

100nF

Y5V

C627

0603

150K

R606

GND

50V

0603

1nF

X7R

C615

GND

95001-6881

SO603

+3V_MIC

LQG18HN39NJ00

LQG18

39nH

L606

TS3V912ID

U602

V-

V+ 1

OUT

GND

16V

0603

100nF

Y5V

C606

0603

47K

R612

noMount=YES

35V

CONT-E

10uF

C605

GND

50V

0603

1nF

X7R

C619

50V

0603

39pF

COG

C624

CONT-R

4.7uF

C601

50V

0603

100pF

COG

C637

LQG18HN39NJ00

LQG18

39nH

L604

16V

0603

100nF

Y5V

C611

GND

LGK2009-0201

LGK2009-02

SO602

50V

0603

39pF

COG

C612

+3.7V

16V

0603

100nF

Y5V

C604

0603

47K

R615

50V

0603

39pF

COG

C607

GND

0603

10K

R609

16V

0603

100nF

Y5V

C628

CONT-R

4.7uF

C610

GPIO1

004:5D;005:7C

GND

16V

0603

100nF

Y5V

C609

50V

0603

1nF

X7R

C620

GND

TS3V912ID

U602

V-

V+ 7

OUT

0603

82K

R618

0603

R603

GND

LGK2009-0201

LGK2009-02

SO601

0603

470K

R619

16V

0603

100nF

Y5V

C608

0603

47K

R613

0603

150K

R604

GND

50V

0603

1nF

X7R

C623

GND

0603

47K

R616

GND

LQG18HN39NJ00

LQG18

39nH

L601

0603

47K

R614

J01001A1944

SO605

GND

MIC_MT+

004:4D

0603

R602

16V

0603

100nF

Y5V

C631

GND

16V

0603

100nF

Y5V

C632

50V

0603

39pF

COG

C622

GND

1215061-03F

PL603

TS3V912ID

U603

V-

V+ 7

OUT

TS3V912ID

U603

V-

V+ 1

OUT

1Fs

BC847BW

SOT-323

Q601 2

50V

0603

220pF

X7R

C635

0603

10K

R617

0603

220pF

C634

50V

X7R

16V

0603

100nF

Y5V

C633

J01001A1944

SO606

L02A

LP2980AIM5X-3_0

MA05B

U601

V_IN

ON-OFF

4NC

5V_OUT

GND

0603

10K

R601

+3V_MIC

0603

47K

R621

GND

16V

0603

100nF

Y5V

C625

J01001A1944

SO604

GND

0603

47K

R620

16V

0603

100nF

Y5V

C626

16V

0603

100nF

Y5V

C630

50V

0603

100pF

COG

C636

GND

+3V_INT_MIC_BAL

16V

0603

100nF

Y5V

C618

+3V_INT_MIC_SINGLE

EAR_MT-

004:3D;008:10B

50V

0603

39pF

COG

C621

+3V_INT_MIC_SINGLE

GND

+3V_INT_MIC_SINGLE

GND

16V

0603

100nF

Y5V

C603

+3V_INT_MIC_BAL

GND

EVK for GM862/S1

0208 6 10 30208SE10944b

cs944b.cir

INTERNAL MICROPHONE SECTION

BALANCED

SINGLE ENDED

BALANCED

INTERNAL MIC

SINGLE ENDED

HANDSET V125

BOOT RX

GND

HOOK

BOOT TX

EAR-

MICR+

MICR-

EAR+

SINGLE ENDED

BALANCED

BALANCED MICROPHONE POLARIZATION

SINGLE ENDED MICROPHONE POLARIZATION

MICROPHONE POLARIZATION REGULATOR

SIGNAL FILTERING

BALANCED MICROPHONE BUFFER +24 dB

DECOUPLING CAPACITORS

SINGLE ENDED MICROPHONE BUFFER +24 dB

SIGNAL FILTERING

INT_MIC+

INT_MIC-

INT_MIC

SINGLE ENDED

INT MIC POWER SELECTION

BALANCED

INT MIC SELECTION

Serdi M. 041201

041201

301101

Locatelli M.

Deperini F.

FORBIDDENVIETATE

RIPRODUZIONE E DIVULGAZIONE REPRODUCTION AND DISCLOSURE

PROJECT A3

DESCRIPTION

DRAWING CODE

FORM

MODIFY

OF SHEETS

DATE

SHEET N.

VERIFIED

PROJECT

DRAWN

PATH /home/users/area

Mod. 067 rev.0 03/01 ANNOTATION

FILE NAME

Mobile Terminals S.p.A.

42 981 0713 1165

1Fs

BC847BW

SOT-323

Q702 2

50V

0603

1nF

X7R

C708

LQG18HN39NJ00

LQG18

39nH

L702

GND

J01001A1944

SO704

J01001A1944

SO703

50V

0603

39pF

COG

C705

GND

0603

10K

R704

50V

0603

470pF

X7R

C729

GND

0603

47K

R713

50V

0603

1nF

X7R

C706

GND GND

GND

50V

0603

39pF

COG

C704

MIC_HF+

004:4D

50V

0603

1nF

X7R

C727

1215061-03F

PL702

50V

0603

1nF

X7R

C707

16V

0603

100nF

Y5V

C716

LGK2009-0201

LGK2009-02

SO701

GND

50V

0603

3.3nF

X7R

C726

1Fs

BC847BW

SOT-323

Q701 2

0603

47K

R712

GND

LQG18HN39NJ00

LQG18

39nH

L703

16V

0603

100nF

Y5V

C712

16V

0603

100nF

Y5V

C721

16V

0603

100nF

Y5V

C719

16V

0603

100nF

Y5V

C718

GND

0603

15K

R711

+3V_EXT_MIC_SINGLE

GND

1615061-08F

PL701

0603

33K

R709

+3V_EXT_MIC_BAL

GND

TS3V912ID

U701

V-

V+ 1

OUT

16V

0603

100nF

Y5V

C722

+3V_EXT_MIC_SINGLE

0603

47K

R717

+3V_EXT_MIC_BAL

J01001A1944

SO705

+3V_EXT_MIC_SINGLE

0603

10K

R708

TS3V912ID

U701

V-

V+ 7

OUT

0603

47K

R715

0603

10K

R707

0603

10K

R720

GND

16V

0603

100nF

Y5V

C709

TS3V912ID

U702

V-

V+ 7

OUT

+3V_EXT_MIC_BAL

LQG18HN39NJ00

LQG18

39nH

L701

+3V_EXT_MIC_SINGLE

16V

0603

100nF

Y5V

C714

16V

0603

100nF

Y5V

C710

CONT-R

4.7uF

C701

MIC_HF-

004:3D

GND

+3V_MIC

0603

33K

R710

CONT-R

4.7uF

C702

16V

0603

100nF

Y5V

C720

GND

0603

470K

R718

50V

0603

470pF

X7R

C728

LGK2009-0201

LGK2009-02

SO702

+3V_EXT_MIC_BAL

0603

5.6K

R719

0603

R702

16V

0603

100nF

Y5V

C724

0603

R703

0603

2.2K

R701

16V

0603

100nF

Y5V

C715

GND

TS3V912ID

U702

V-

V+ 1

OUT

16V

0603

100nF

Y5V

C717

GND

0603

10K

R706

16V

0603

100nF

Y5V

C725

0603

47K

R714

GND

+3V_EXT_MIC_BAL

50V

0603

39pF

COG

C703

GND

+3V_EXT_MIC_SINGLE

GND

16V

0603

100nF

Y5V

C711

0603

47K

R716

GND

0603

10K

R705

+3V_EXT_MIC_SINGLE

16V

0603

100nF

Y5V

C713

16V

0603

100nF

Y5V

C723

EVK for GM862/S1

30208SE10944b

cs944b.cir

EXTERNAL MICROPHONE SECTION

71 00208

EXTERNAL MIC

SINGLE ENDED

SINGLE ENDED MICROPHONE BUFFER +10 dB BALANCED

BALANCED

BALANCED MICROPHONE POLARIZATION

SINGLE ENDED MICROPHONE POLARIZATION

NOISE FILTERING

SINGLE ENDED

EXTERNAL MIC

BALANCED

NOISE FILTERING

BALANCED MICROPHONE BUFFER +10 dB

DECOUPLING CAPACITORS

EXT_MIC+

EXT_MIC-

EXT_MIC

SINGLE ENDED

EXT MIC POWER SELECTION

BALANCED

EXT MIC SELECTION

Serdi M. 041201

041201

301101

Locatelli M.

Deperini F.

FORBIDDENVIETATE

RIPRODUZIONE E DIVULGAZIONE REPRODUCTION AND DISCLOSURE

PROJECT A3

DESCRIPTION

DRAWING CODE

FORM

MODIFY

OF SHEETS

DATE

SHEET N.

VERIFIED

PROJECT

DRAWN

PATH /home/users/area

Mod. 067 rev.0 03/01 ANNOTATION

FILE NAME

Mobile Terminals S.p.A.

42 981 0713 1165

50V

0603

10pF

COG

C817

0603

R806

50V

0603

39pF

COG

C808

GND

LQG18HN39NJ00

LQG18

39nH

L804

GND

16V

CONT-E

220uF

C820

GND

J01001A1944

SO806

LQG18HN39NJ00

LQG18

39nH

L801

50V

0603

39pF

COG

C810

J01001A1944

SO807

GND

LM4862M

U802

6VDD

BYPASS

IN+

8VC2

SHUTDOWN

7GND

IN-

5VC1

6.3V

0603

1uF

X5R

C818

GND

+3.7V

1215061-03F

PL804

50V

0603

10pF

COG

C803

GND

LQG18HN39NJ00

LQG18

39nH

L803

EAR_HF-

004:3D;009:11C

1215061-03F

PL803

0603

1nF

C807

50V

X7R

50V

0603

1nF

X7R

C809

GND

0603

R807

50V

0603

39pF

COG

C812

50V

0603

39pF

COG

C811 16V

0603

100nF

Y5V

C825

MUTE

005:5B;008:10D;009:11C

GND

0603

R809

0603

R810

GND

0603

R812

GND

J01001A1944

SO808

6.3V

0603

1uF

X5R

C801

GND

0603

56K

R802

50V

0603

1nF

X7R

C815

LM4862M

U801

6VDD

BYPASS

IN+

8VC2

SHUTDOWN

7GND

IN-

5VC1

GND

EAR_HF+

004:3D;009:11B

EAR_MT+

004:3D;006:10E

0603

100K

R803

GND

16V

0603

100nF

Y5V

C826

16V

0603

100nF

Y5V

C821

16V

0603

100nF

Y5V

C802

50V

0603

39pF

COG

C804

EAR_MT-

004:3D;006:10D

GND

50V

0603

1nF

X7R

C813

GND

16V

0603

100nF

Y5V

C829

J01001A1944

SO805

LGY6502-0600

LGY650X

SO801

GND

16V

0603

100nF

Y5V

C828

GND

0603

56K

R801

MUTE

005:5B;008:10B;009:11C

GND

0603

R811

GND

LQG18HN39NJ00

LQG18

39nH

L806

16V

0603

100nF

Y5V

C830

LQG18HN39NJ00

LQG18

39nH

L805

16V

CONT-E

220uF

C823

16V

0603

100nF

Y5V

C822

50V

0603

1nF

X7R

C806

+3.7V

16V

0603

100nF

Y5V

C827

16V

CONT-E

220uF

C819

GND

50V

0603

1nF

X7R

C814

LGY6502-0600

LGY650X

SO803

GND

16V

CONT-E

220uF

C824

LGY6502-0600

LGY650X

SO802

GND

0603

56K

R804

LQG18HN39NJ00

LQG18

39nH

L802

16V

0603

100nF

Y5V

C816

50V

0603

39pF

COG

C805

LGY6502-0600

LGY650X

SO804

GND

cs944b.cir

81 0

INTERNAL EAR (HANDSET)/ EXTERNAL EAR (HANDSFREE)

0208

EVK for GM862/S1

30208SE10944b

BRIDGED

NOISE FILTERING

INTERNAL EAR

NOISE FILTERING

SINGLE ENDED

INTERNAL EAR

BRIDGED

EXTERNAL EAR

SINGLE ENDED

NOISE FILTERING

EXTERNAL EAR

NOISE FILTERING

INTERNAL EAR AMPLIFIER +6dB

LOW VOLTAGE EXTERNAL EAR AMPLIFIER +12dB

EXT_EAR+

EXT_EAR-

INT_EAR+

INT_EAR-

MUTE CONTROLLED

ALWAYS ON

AMPLI POWER CONTROL

ALWAYS ON

AMPLI POWER CONTROL

MUTE CONTROLLED

Serdi M. 041201

041201

301101

Locatelli M.

Deperini F.

0603

10K

R904

TDA8943SF-N1

SOT110-1

U901

9NC

MODE

VCC

GND

IN+

3OUT+

SVR

1OUT-

IN-

50V

0603

1nF

X7R

C905

noMount=YES

GND

EAR_HF+

004:3D;008:10D

GND

MUTE

005:5B;008:10B;008:10D

GND

+12V

BLM21

220

L902

50V

0603

39pF

COG

C904

noMount=YES

35V

1000uF

C901

GND

BLM21

220

L901

0603

56K

R901

noMount=YES

FCMM0502

SO901

16V

0603

100nF

Y5V

C912

1215061-03F

PL901

FORBIDDENVIETATE

RIPRODUZIONE E DIVULGAZIONE REPRODUCTION AND DISCLOSURE

PROJECT A3

DESCRIPTION

DRAWING CODE

FORM

MODIFY

OF SHEETS

DATE

SHEET N.

VERIFIED

PROJECT

DRAWN

PATH /home/users/area

Mod. 067 rev.0 03/01 ANNOTATION

FILE NAME

Mobile Terminals S.p.A.

42 981 0713 1165

50V

0603

39pF

COG

C903

noMount=YES

16V

0603

100nF

Y5V

C911

GND

16V

0603

100nF

Y5V

C902

GND

16V

0603

100nF

Y5V

C908

0603

10K

R903

GND

0603

15K

R902

35V

CONT-E

10uF

C910

50V

0603

1nF

X7R

C906

noMount=YES

GND

EAR_HF-

004:3D;008:10D

GND

50V

0603

1.5nF

X7R

C913

HIGH POWER EXTERNAL EAR (HANDSFREE)

0208

EXTERNAL EAR

NOISE FILTERING

cs944b.cir

30208SE10944b9

HIGH POWER BRIDGED

EVK for GM862/S1

HIGH POWER EXT EAR AMPLIFIER (6W)

NOTE:

Heat Sink may be required

Refer to chip datasheet

MUTE CONTROLLED

ALWAYS ON

AMPLI POWER CONTROL

MIN 8 OHM

Serdi M. 041201

041201

301101

Locatelli M.

Deperini F.

Telit GM862-QUAD Hardware User guide

1vv0300692, Rev. ISSUE#0, - 04/10/2005

page 65 of 69

11 Annex B - Camera EVB schematics

Telit Communications S p A GM862 Data Terminal Module User Manual

Telit Communications S.p.A. Data Terminal Module

User Manual

Navigation menu

Namespaces

Views

Navigation