Rainbow Electronics GM862-QUAD-PY User Manual

GM862-QUAD / PY Hardware User Guide

GM862-QUAD-PY, GM862-QUAD HW User Guide 1vv0300748 Rev. 5 - 20/09/07

GM862-QUAD / PY Hardware User Guide

1vv0300748 Rev. 5 - 20/09/07

Contents

1 Overview ........................................................................................................................... 6

2 Dimensions ....................................................................................................................... 7

3 Interface connectors on GM862-QUAD / PY .................................................................. 8

3.1 Description .............................................................................................................................. 8

3.2 Connectors Position .............................................................................................................. 8

3.3 Board to Board Connector .................................................................................................... 9

3.3.1 Molex 52991-0508 (male) GM862 Connector PIN-OUT ................................................................10

3.3.2 Antenna Connector .........................................................................................................................12

4 Antenna ........................................................................................................................... 13

4.1 GSM Antenna Requirements ............................................................................................... 13

4.2 GSM Antenna - Installation Guidelines .............................................................................. 14

4.3 Logic level specifications .................................................................................................... 14

4.3.1 Reset signal ....................................................................................................................................15

5 Hardware Commands .................................................................................................... 16

5.1 Turning ON the GM862-QUAD / PY ..................................................................................... 16

5.2 Turning OFF the GM862-QUAD / PY ................................................................................... 18

5.2.1 Hardware Shutdown .......................................................................................................................18

5.2.2 Hardware Unconditional Restart .....................................................................................................19

6 Power Supply ................................................................................................................. 21

6.1 Power Supply Requirements ............................................................................................... 21

6.2 General Design Rules .......................................................................................................... 22

6.2.1 Electrical Design Guidelines ...........................................................................................................22

6.2.1.1 + 5V input Source Power Supply Design Guidelines .................................................................22

6.2.1.2 + 12V input Source Power Supply Design Guidelines ...............................................................24

6.2.1.3 Battery Source Power Supply Design Guidelines ......................................................................26

6.2.1.4 Battery Charge control Circuitry Design Guidelines ...................................................................26

6.2.2 Thermal Design Guidelines ............................................................................................................28

6.2.3 Power Supply PCB layout Guidelines ............................................................................................29

7 Serial Ports ..................................................................................................................... 30

7.1 Level translation ................................................................................................................... 32

7.2 5V UART level translation .................................................................................................... 34

8 Audio Section Overview ................................................................................................ 36

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8.1 Microphone Paths Characteristic and Requirements ....................................................... 38

8.2 General Design Rules .......................................................................................................... 41

8.3 Other Considerations ........................................................................................................... 41

8.4 Microphone Biasing ............................................................................................................. 42

8.4.1 Balanced Microphone Biasing ........................................................................................................42

8.4.2 Unbalanced Microphone Biasing ....................................................................................................43

8.5 Microphone Buffering .......................................................................................................... 45

8.5.1 Buffered Balanced Mic ....................................................................................................................45

8.5.2 Buffered Unbalanced (Single Ended) Microphone .........................................................................47

9 OUTPUT LINES (Speaker) .............................................................................................. 50

9.1 Short Description ................................................................................................................. 50

9.2 Output Lines Characteristics .............................................................................................. 51

9.3 General Design Rules .......................................................................................................... 52

9.3.1 Noise Filtering .................................................................................................................................52

9.4 Handset Earphone Design ................................................................................................... 53

9.5 Hands-Free Earphone (Low Power) Design ....................................................................... 54

9.6 Car Kit Speakerphone Design ............................................................................................. 55

10 General Purpose I/O ....................................................................................................... 56

10.1 GPIO Logic levels ................................................................................................................. 58

10.2 Using a GPIO pin as INPUT ................................................................................................. 59

10.3 Using the RF Transmission Control GPIO4 ....................................................................... 59

10.4 Using the RFTXMON Output GPIO5 .................................................................................... 59

10.5 Using the Alarm Output GPIO6 ........................................................................................... 59

10.6 Using the Buzzer Output GPIO7 .......................................................................................... 60

11 ADC section .................................................................................................................... 61

11.1 ADC converter ...................................................................................................................... 61

11.1.1 Description ......................................................................................................................................61

11.1.2 Using ADC Converter .....................................................................................................................61

12 Indication of network service availability ..................................................................... 62

13 Mounting the GM862 Modules on your Board ............................................................. 63

13.1 Antenna Coaxial Cable Fixing ............................................................................................. 64

13.2 Precautions ........................................................................................................................... 65

14 Conformity Assessment Issues .................................................................................... 66

15 SAFETY RECOMMANDATIONS..................................................................................... 67

16 Document Change Log .................................................................................................. 68

This document is relating to the following products:

GM862-QUAD / PY Hardware User Guide

1vv0300748 Rev. 5 - 20/09/07

GM862-QUAD 3 990 250 659 GM862-QUAD-PY 3 990 250 658

GM862-QUAD / PY Hardware User Guide

1vv0300748 Rev. 5 - 20/09/07

DISCLAIMER

The information contained in this document is the proprietary information of Telit Communications S.p.A. and its affiliates (“TELIT”). The contents are confidential and any disclosure to persons other than the officers, employees, agents or subcontractors of the owner or licensee of this document, without the prior written consent of Telit, is strictly prohibited.

Telit makes every effort to ensure the quality of the information it makes available. Notwithstanding the foregoing, Telit does not make any warranty as to the information contained herein, and does not accept any liability for any injury, loss or damage of any kind incurred by use of or reliance upon the information.

Telit disclaims any and all responsibility for the application of the devices characterized in this document, and notes that the application of the device must comply with the safety standards of the applicable country, and where applicable, with the relevant wiring rules.

Telit reserves the right to make modifications, additions and deletions to this document due to typographical errors, inaccurate information, or improvements to programs and/or equipment at any time and without notice. Such changes will, nevertheless be incorporated into new editions of this document.

GM862-QUAD / PY Hardware User Guide

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1 Overview

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

Telit GM862-QUAD / PY module.

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 cannot 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 / PY module.

For further hardware details that may not be explained in this document refer to the Telit GM862-QUAD / PY Product Description document where all the hardware information is reported.

NOTICE

(EN) The integration of the GSM/GPRS GM862-QUAD / PY cellular module within user application shall be done according to the design rules described in this manual.

(IT) L’integrazione del modulo cellulare GSM/GPRS GM862-QUAD / PY all’interno dell’applicazione dell’utente dovrà rispettare le indicazioni progettuali descritte in questo manuale.

(DE) Die integration des GM862-QUAD / PY GSM/GPRS Mobilfunk-Moduls in ein Gerät muß gemäß der in diesem Dokument beschriebenen Kunstruktionsregeln erfolgen

(SL) Integracija GSM/GPRS GM862-QUAD / PY modula v uporabniški aplikaciji bo morala upoštevati projektna navodila, opisana v tem piročniku.

(SP) La utilización del modulo GSM/GPRS GM862-QUAD / PY debe ser conforme a los usos para los cuales ha sido deseñado descritos en este manual del usuario.

(FR) L’intégration du module cellulaire GSM/GPRS GM862-QUAD / PY dans l’application de l’utilisateur

sera faite selon les règles de conception décrites dans ce manuel.

GM862-QUAD / PY

The information presented in this document is believed to be accurate and reliable. However, no responsibility is assumed by Telit Communications S.p.A. 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 Telit Communications S.p.A. other than for circuitry embodied in Telit products. This document is subject to change without notice.

2 Dimensions

The Telit GM862-QUAD / PY module overall dimension are:

• Length: 43.9 mm

• Width: 43.9 mm

• Thickness: 6.9 mm

• Volume: ≅ 13 cm

The layout is shown in the following figure:

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GM862-QUAD / PY Hardware User Guide

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3 Interface connectors on GM862-QUAD /

3.1 Description

The Telit GM862-QUAD / PY is provided of the following interfaces:

• GSM antenna connector

• Board To Board Interface connector

• SIM Card Reader

The Telit GM862-QUAD / PY board to board connector is a CSTP 50 pin vertical SMD Molex 52991–0508

(male).

3.2 Connectors Position

SIM Card Holder

Board to Board Connector

GSM Antenna Connector

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3.3 Board to Board Connector

Molex 52991-0508 (male) GM862 Connector LAY-OUT

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3.3.1 Molex 52991-0508 (male) GM862 Connector PIN-OUT

Pin Signal I/O Function

1 VBATT

2 GND - Ground Power

3 VBATT - Main power supply Power

4 GND - Ground Power

5 VBATT - Main power supply Power

6 A/D - A/D converter @ 11 bit (Input Impedance >100Kohm) Max 2V input

7 VBATT - Main power supply Power

8 CHARGE AI Battery Charger Input Power

9 EAR_HF+ AO Handsfree ear output, phase + Audio

10 EAR_MT- AO Handset earphone signal output, phase - Audio

11 EAR_HF- AO Handsfree ear output, phase - Audio

12 EAR_MT+ AO Handset earphone signal output, phase + Audio

13 MIC_HF- AI Handsfree microphone input; phase - Audio

14 MIC_MT+ AI Handset microphone signal input; phase+ Audio

15 MIC_HF+ AI Handsfree microphone input; phase + Audio

16 MIC_MT- AI Handset microphone signal input; phase- Audio

17 ON_OFF I Input command for switching power ON or OFF (toggle command).

18 AXE I Handsfree switching

19 SIMIO I/O External SIM signal - Data I/O 1.8V/3V ONLY

20 C103/TXD I Serial data input (TXD) from DTE CMOS 2.8V

21 PWRMON O

22 SIMVCC - External SIM signal – Power (3) 1.8V/3V ONLY

23 RESET I Reset input -

24 SIMRST O External SIM signal – Reset 1.8V/3V ONLY

25 RESERVED - Reserved -

26 SIMCLK O External SIM signal – Clock 1.8V/3V ONLY

27 SIMIN I/O External SIM signal – Presence (active low)

28 GPO2 / JDR O

29 C106/CTS O Output for Clear to send signal (CTS) to DTE CMOS 2.8V

30 C125/RING O Output for Ring indicator signal (RI) to DTE CMOS 2.8V

31 GPI1 I General purpose input transistor base

32 GPIO8 I/O Configurable general purpose I/O pin CMOS 2.8V

Main power supply Power

Module Status ON indication (Signal output for power on/off control of external devices

General purpose output (Open Collector) / Jammer Detect Report

Internal

Pull up

47KΩ

100KΩ

1KΩ

47KΩ

Open Collector

Pull Up to

VBATT

CMOS 2.8V

Type

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Pin Signal I/O Function

33 C107/DSR O Output for Data set ready signal (DSR) to DTE CMOS 2.8V

34 GPIO9 I/O Configurable general purpose I/O pin CMOS 2.8V

35 TX_TRACE O RESERVED on GM862-QUAD, Python Debug on GM862-QUAD-PY (TX data) CMOS 2.8V

36 C109/DCD O Output for Data carrier detect signal (DCD) to DTE CMOS 2.8V

37 C104/RXD O Serial data output to DTE CMOS 2.8V

38 GPIO10 I/O Configurable general purpose I/O CMOS 2.8V

39 STAT_LED O Status indicator led Open Collector

40 GPIO11 I/O Configurable general purpose I/O pin 4.7 Kohm CMOS 2.8V

41 RX_TRACE I RESERVED on GM862-QUAD, Python Debug on GM862-QUAD-PY (RX data) CMOS 2.8V

42 GPIO12 I/O Configurable general purpose I/O pin 47 Kohm CMOS 2.8V

43 C108/DTR I Input for Data terminal ready signal (DTR) from DTE CMOS 2.8V

44 GPIO13 I/O Configurable general purpose I/O pin CMOS 2.8V

45 C105/RTS I Input for Request to send signal (RTS) from DTE CMOS 2.8V

46 GPIO3 I/O Configurable general purpose I/O pin 47 Kohm CMOS 2.8V

47 GPIO4 I/O Configurable general purpose I/O pin / TX Disable Control 4.7 Kohm CMOS 2.8V

GPIO5 /

RFTXMON

GPIO6

/ ALARM I/O

GPIO7

/ BUZZER I/O

I/O Configurable general purpose I/O pin / Transmitter ON Monitor CMOS 2.8V

Configurable general purpose I/O pin / ALARM

Configurable general purpose I/O pin / BUZZER

Internal

Pull up

CMOS 2.8V

Type

(1) For the exclusive use of the Technical Support Service (2) An earphone with a 150 ohm impedance can be directly connected to EAR+ and EAR– (3) On this pin a maximum of 10nF bypass capacitor is allowed.

Note: If not used, almost all pins should be left disconnected. The only exceptions are the following pins:

pin signal 1,3,5,7 2,4,8 17 20 23 37 45

VBATT

GND

ON/OFF*

TXD

RESET*

RXD

RTS1

RTS should be connected to the GND (on the module side) if flow control is not used

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3.3.2 Antenna Connector

The Telit GM862-QUAD / PY includes one 50 Ohm MMCX coaxial female RF connector. On the user

application side the following connector must be used:

a) Telegärtner MMCX angle plug crimp - Order n. J01340A0121

NOTE: be very careful when connecting the Telit GM862-QUAD/PY RF connector. The RF connector can

be damaged if not connected with the proper antenna RF connector. The minimum number of insertion cycles are recommended.

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4 Antenna

4.1 GSM Antenna Requirements

The antenna for a Telit GM862-QUAD/PY device shall fulfill the following requirements:

Frequency range

Bandwidth

Gain Impedance Input power VSWR absolute max VSWR recommended

Furthermore if the device is developed for the US market and/or Canada market, it shall comply to the FCC and/or IC approval requirements:

This device is to be used only for mobile and fixed application. The antenna(s) used for this transmitter must be installed to provide a separation distance of at least 20 cm from all persons and must not be co-located or operating in conjunction with any other antenna or transmitter. End-Users must be provided with transmitter operation conditions for satisfying RF exposure compliance. OEM integrators must ensure that the end user has no manual instructions to remove or install the GM862-QUAD/PY module. Antennas used for this OEM module must not exceed 3dBi gain for mobile and fixed operating configurations.

Depending by frequency band(s) provided by the network operator, the customer shall use the most suitable antenna for that/those band(s) 80 MHz in EGSM 900, 70 MHz if GSM 850, 170 MHz in DCS, 140 MHz PCS band Gain < 3dBi 50 ohm > 2 W peak power <= 10:1

<= 2:1

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4.2 GSM Antenna - Installation Guidelines

• Install the antenna in a place covered by the GSM signal.

• The Antenna must be installed to provide a separation distance of at least 20 cm from all persons

and must not be co-located or operating in conjunction with any other antenna or transmitter;

• Antenna shall not be installed inside metal cases

• Antenna shall be installed also according Antenna manufacturer instructions.

4.3 Logic level specifications

Where not specifically stated, all the interface circuits work at 2.8V CMOS logic levels. The following

table shows the logic level specifications used in the Telit GM862-QUAD/PY interface circuits:

Absolute Maximum Ratings -Not Functional

Parameter Min Max

Input level on any digital pin when on Input voltage on analog pins when on Voltage on Buffered pins

Operating Range - Interface levels (2.8V CMOS)

Level Min Max

Input high level 2.1V 3.3V

Input low level 0V 0.5V

Output high level 2.2V 3.0V

Output low level 0V 0.35V

For 2,0V signals:

Operating Range - Interface levels (2.0V CMOS)

Level Min Max

Input high level 1.6V 3.3V

Input low level 0V 0.4V

Output high level 1,65V 2.2V Output low level 0V 0.35V

-0.3V +3.6V

-0.3V +3.0 V

-0.3V 25V

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Current characteristics

Level Typical

Output Current 1mA

Input Current 1uA

4.3.1 Reset signal

Signal Function I/O Pin

RESET Phone reset I 23 (connector SO301)

RESET is used to reset the GM862-QUAD/PY modules. Whenever this signal is pulled low, the GM862 is

reset. When the device is reset it stops any operation. After the release of the reset GM862-QUAD and GM862-QUAD-PY are unconditionally rebooted, without doing any detach operation from the network where it is registered. This behaviour is not a proper shut down because any GSM device is requested to issue a detach request on turn off. For this reason the Reset signal must not be used to normally shutting down the device, but only as an emergency exit in the rare case the device remains stuck waiting for some network response. The RESET is internally controlled on start-up to achieve always a proper power-on reset sequence, so there's no need to control this pin on start-up. It may only be used to reset a device already on that is not responding to any command.

NOTE: do not use this signal to power off the GM862-QUAD-PY. Use the ON/OFF signal (Pin 17 of SO301) to perform this function or the AT#SHDN command.

Reset Signal Operating levels:

Signal Min Max

RESET Input high 2.0V* 2.2V RESET Input low 0V 0.2V

* this signal is internally pulled up so the pin can be left floating if not used.

If unused, this signal may be left unconnected. If used, then it must always be connected with an open collector transistor, to permit to the internal circuitry the power on reset and under voltage lockout functions.

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5 Hardware Commands

5.1 Turning ON the GM862-QUAD / PY

To turn on the GM862-QUAD / PY 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:

ON#

Power ON impulse

GND

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 / PY power regulator and improper power on/off of the module. The line ON# must be connected only in open collector configuration.

NOTE: The GM862-QUAD/PY turns fully on also by supplying power to the Charge pad (Module provided with a battery on the VBATT pads).

TIP: To check if the device has powered on, the hardware line PWRMON should be monitored. After 900ms the line raised up the device could be considered powered on. PWRMON line rises up also when supplying power to the Charge pad

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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):

10k

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

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5.2 Turning OFF the GM862-QUAD / PY

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

• by software command (see GM862-QUAD / PY 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.

5.2.1 Hardware Shutdown

To turn OFF the GM862-QUAD / PY 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 PWRMON should be monitored. When PWRMON goes low, the device has powered off.

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5.2.2 Hardware Unconditional Restart

To unconditionally Shutdown the GM862-QUAD / PY the pin RESET# must be tied low for at least 200 milliseconds and then released. The maximum current that can be drained from the RESET# pin is 0,15 mA. A simple circuit to do it is:

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 / PY power regulator and improper functioning of the module. The line RESET# must be connected only in open collector configuration.

TIP: The unconditional hardware Restart should be always implemented on the boards and software should use it as an emergency exit procedure.

Unconditional Restart impulse

RESET#

GND

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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):

10k

The hardware unconditional restart 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 stacked 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 reset shall be issued.

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6 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.

6.1 Power Supply Requirements

POWER SUPPLY

Nominal Supply Voltage 3.8 V Max Supply Voltage 4.2 V Supply voltage range 3.4 V - 4.2 V

CONSUMPTIONS

Mode Average (mA) Mode description

IDLE mode

AT+CFUN=1 23,9 Normal mode: full functionality of the module AT+CFUN=4 22 Disabled TX and RX; module is not registered on the network

Power saving: CFUN=0 module registered on the network and can

receive voice call or an SMS; but it is not possible to send AT

AT+CFUN=0 or

AT+CFUN=5

RX mode

1 slot in downlink 52,3 2 slot in downlink 65,2 3 slot in downlink 78,6 4 slot in downlink 88,4

GSM TX and RX mode

Max power level 200,1

GPRS (class 10) TX and RX mode

Max power level 370,8

7,20 / 3,562

commands; module wakes up with an unsolicited code (call or

SMS) or rising RTS line. CFUN=5 full functionality with power

saving; module registered on the network can receive incoming

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.

Stand by mode; no call in progress

calls and SMS

GSM Receiving data mode

GSM Sending data mode Min power level 78,1

GPRS Sending data mode Min power level 123,7

Worst/best case depends on network configuration and is not under module control

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