Telit Communications S p A GL865Q Quadband GSM/ GPRS Module User Manual 1vv0300910 GL865 Hardware User Guide r1

Telit Communications S.p.A. Quadband GSM/ GPRS Module 1vv0300910 GL865 Hardware User Guide r1

User Manual

                  GL865 Hardware User Guide 1vv0300910 Rev.1 – 2011-07-22
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 2 of 79  APPLICABILITY TABLE  PRODUCT GL865 QUAD GL865 DUAL
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 3 of 79  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 application note.  All rights reserved.  © 2009, 2010 Telit Communications S.p.A.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 4 of 79   Contents 1. INTRODUCTION ......................................................................................................................................................... 6 1.1. SCOPE ......................................................................................................................................................................... 6 1.2. AUDIENCE .................................................................................................................................................................... 6 1.3. CONTACT INFORMATION, SUPPORT .................................................................................................................................. 6 1.4. DOCUMENT ORGANIZATION ............................................................................................................................................ 6 1.5. TEXT CONVENTIONS ....................................................................................................................................................... 7 1.6. RELATED DOCUMENTS ................................................................................................................................................... 8 1.7. DOCUMENT HISTORY ..................................................................................................................................................... 8 2. OVERVIEW .............................................................................................................................................................. 10 3. GL865 MECHANICAL DIMENSIONS .......................................................................................................................... 12 4. GL865 MODULE CONNECTIONS ............................................................................................................................... 13 4.1. PIN-OUT .................................................................................................................................................................. 13 4.2. PIN LAYOUT ............................................................................................................................................................... 16 5. HARDWARE COMMANDS ........................................................................................................................................ 17 5.1. AUTO-TURNING ON THE GL865 ................................................................................................................................... 17 5.2. TURNING OFF THE GL865 ........................................................................................................................................... 19 5.3. RESETTING THE GL865 ................................................................................................................................................ 21 5.3.1. Hardware Unconditional restart .................................................................................................................... 21 6. POWER SUPPLY ....................................................................................................................................................... 23 6.1. POWER SUPPLY REQUIREMENTS ..................................................................................................................................... 23 6.2. POWER CONSUMPTION ................................................................................................................................................ 24 6.3. GENERAL DESIGN RULES ............................................................................................................................................... 25 6.3.1. Electrical Design Guidelines ........................................................................................................................... 25 6.3.2. Thermal Design Guidelines ............................................................................................................................ 29 6.3.3. Power Supply PCB layout Guidelines ............................................................................................................. 30 7. ANTENNA ................................................................................................................................................................ 32 7.1. GSM ANTENNA REQUIREMENTS .................................................................................................................................... 32 7.2. GSM ANTENNA - PCB LINE GUIDELINES .......................................................................................................................... 33 7.3. GSM ANTENNA - INSTALLATION GUIDELINES ................................................................................................................... 37 8. LOGIC LEVEL SPECIFICATIONS .................................................................................................................................. 38 8.1. RESET SIGNAL ............................................................................................................................................................. 39 9. SERIAL PORTS .......................................................................................................................................................... 41 9.1. MODEM SERIAL PORT ............................................................................................................................................. 41 9.2. RS232 LEVEL TRANSLATION .......................................................................................................................................... 43 9.3.  ................................................................................................................................................................................ 46 9.4. 5V UART LEVEL TRANSLATION ...................................................................................................................................... 47 10. AUDIO SECTION OVERVIEW ................................................................................................................................ 49
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 5 of 79  10.1. ELECTRICAL CHARACTERISTICS ........................................................................................................................................ 52 10.1.1. Input Lines ..................................................................................................................................................... 52 10.1.2. Output Lines................................................................................................................................................... 53 11. GENERAL PURPOSE I/O ....................................................................................................................................... 55 11.1. GPIO LOGIC LEVELS ..................................................................................................................................................... 56 11.2. USING A GPIO PAD AS INPUT ...................................................................................................................................... 57 11.3. USING A GPIO PAD AS OUTPUT .................................................................................................................................. 57 11.4. USING THE RFTXMON OUTPUT GPIO5 ......................................................................................................................... 57 11.5. USING THE ALARM OUTPUT GPIO6 ............................................................................................................................... 58 11.6. USING THE BUZZER OUTPUT GPIO7 ............................................................................................................................... 58 11.7. MAGNETIC BUZZER CONCEPTS ....................................................................................................................................... 59 1.1.1 Short Description .................................................................................................................................................... 59 11.7.1. Frequency Behaviour ..................................................................................................................................... 60 11.7.2. Power Supply Influence .................................................................................................................................. 60 11.7.3. Working Current Influence ............................................................................................................................. 61 11.8. STAT LED INDICATION OF NETWORK SERVICE AVAILABILITY ................................................................................................. 61 11.9. SIMIN DETECTION ...................................................................................................................................................... 62 11.10. RTC BYPASS OUT .................................................................................................................................................... 64 11.11. SIM HOLDER IMPLEMENTATION ................................................................................................................................ 64 12. DAC AND ADC SECTION ....................................................................................................................................... 65 12.1. DAC CONVERTER ........................................................................................................................................................ 65 12.1.1. Description ..................................................................................................................................................... 65 12.1.2. Enabling DAC ................................................................................................................................................. 66 12.1.3. Low Pass Filter Example................................................................................................................................. 66 12.2. ADC CONVERTER ........................................................................................................................................................ 67 12.2.1. Description ..................................................................................................................................................... 67 12.2.2. Using ADC Converter ..................................................................................................................................... 67 12.3. DEBUG OF THE GL865 IN PRODUCTION ........................................................................................................................... 67 13. MOUNTING THE GL865 ON YOUR BOARD ........................................................................................................... 69 13.1. GENERAL ................................................................................................................................................................... 69 13.2. MODULE FINISHING & DIMENSIONS ................................................................................................................................ 69 13.3. RECOMMENDED FOOT PRINT FOR THE APPLICATION ........................................................................................................... 70 13.4. SOLDER PASTE ............................................................................................................................................................ 71 13.4.1. GL865 Solder reflow ....................................................................................................................................... 71 14. PACKING SYSTEM ................................................................................................................................................ 73 14.1. MOISTURE SENSIBILITY ................................................................................................................................................. 74 15. CONFORMITY ASSESSMENT ISSUES ..................................................................................................................... 75 16. SAFETY RECOMMANDATIONS ............................................................................................................................. 76
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 6 of 79  1.  Introduction 1.1. Scope The aim of this document is the description of some hardware solutions useful for developing a product with the Telit GL865 module. 1.2. Audience This  document  is  intended  for  Telit  customers,  who  are  integrators, about to implement their applications using our GL865 modules. 1.3. Contact Information, Support For general contact, technical support, to report documentation errors and  to  order  manuals,  contact  Telit’s  Technical  Support  Center (TTSC) at:  TS-EMEA@telit.com TS-NORTHAMERICA@telit.com TS-LATINAMERICA@telit.com TS-APAC@telit.com  Alternatively, use:  http://www.telit.com/en/products/technical-support-center/contact.php For detailed information about where you can buy the Telit modules or for recommendations on accessories and components visit:  http://www.telit.com To register for product news and announcements or for product questions contact Telit’s Technical Support Center (TTSC). Our aim is to make this guide as helpful as possible. Keep us informed of your comments and suggestions for improvements. Telit appreciates feedback from the users of our information.           1.4. Document Organization  This document contains the following chapters:  Chapter  1:  “Introduction”  provides  a  scope  for  this  document,  target audience, contact and support information, and text conventions.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 7 of 79   Chapter 2: “Overview” provides an overview of the document.  Chapter 3: “GL865 Mechanical Dimensions”   Chapter  4:  “GL865  Module  Connections”  deals  with  the  pin  out configuration and layout.  Chapter  5:  “Hardware  Commands”  How  to  operate  on  the  module  via hardware.  Chapter 6: “Power supply” Power supply requirements and general design rules.  Chapter 7: “Antenna” The antenna connection and board layout design are the most important parts in the full product design.  Chapter 8: “Logic Level specifications” Specific values adopted in the implementation of logic levels for this module.            Chapter  9:  “Serial  ports”  The  serial  port  on  the  Telit  GL865  is  the core of the interface between the module and OEM hardware  Chapter 10: “Audio Section overview” Refers to the audio blocks of the Base Band Chip of the GL865 Telit Modules.  Chapter 11: “General Purpose I/O” How the general purpose I/O pads can be configured.  Chapter  12  “DAC  and  ADC  Section”  Deals  with  these  two  kind  of converters.  Chapter  13:  “Mounting  the  GL865  on  the  application  board” Recommendations and specifics on how to mount the module on the user’s board.            1.5. Text Conventions  Danger  –  This  information  MUST  be  followed  or  catastrophic  equipment failure or bodily injury may occur.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 8 of 79  Caution  or  Warning  –  Alerts  the  user  to  important  points  about integrating  the  module,  if  these  points  are  not  followed,  the  module and end user equipment may fail or malfunction.  Tip or Information – Provides advice and suggestions that may be useful when integrating the module.  All dates are in ISO 8601 format, i.e. YYYY-MM-DD.  1.6. Related Documents  • Telit's GSM/GPRS Family Software User Guide, 1vv0300784 • Audio settings application note , 80000NT10007a • Digital Voice Interface Application Note, 80000NT10004a • GL865 Product description, 80370ST10080a • SIM Holder Design Guides, 80000NT10001a • AT Commands Reference Guide, 80000ST10025a • Telit EVK2 User Guide, 1vv0300704                   1.7. Document History  RReevviissiioonn  DDaattee  CChhaannggeess  ISSUE#0  2011-01-05  First ISSUE ISSUE#1  2011-07-22  Add FCC IC note in Safety recommendations
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 9 of 79
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 10 of 79  2.  Overview The  aim  of  this  document  is  the  description  of  some  hardware solutions  useful  for  developing  a  product  with  the  Telit  GL865 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 GL865 module. For  further  hardware  details  that  may  not  be explained  in  this document  refer  to  the  Telit  GL865  Product  Description  document where all the hardware information is reported.  NOTICE: (EN) The integration of the GSM/GPRS GL865 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 GL865  all’interno dell’applicazione dell’utente dovrà rispettare le indicazioni progettuali descritte in questo manuale.  (DE) Die Integration des GL865 GSM/GPRS Mobilfunk-Moduls in ein Gerät muß gemäß der in diesem Dokument beschriebenen Kunstruktionsregeln erfolgen.  (SL) Integracija GSM/GPRS GL865 modula v uporabniški aplikaciji bo morala upoštevati projektna navodila, opisana v tem piročniku.  (SP) La utilización del modulo GSM/GPRS GL865 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 GL865 dans l’application de l’utilisateur sera faite selon les règles de conception décrites dans ce manuel.  (HE)   The  information  presented  in  this  document  is  believed  to  be accurate and reliable. However, no responsibility is assumed by GL865
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 11 of 79  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.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 12 of 79  3.  GL865 Mechanical Dimensions The GL865 overall dimensions are:  • Length:     24.4 mm • Width:     24.4 mm  • Thickness:     2.7 mm • Weight    2.48 g
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 13 of 79  4.  GL865 module connections  4.1. PIN-OUT Pad  Signal  I/O  Function  Note  Type Audio 20  EAR-  AO Earphone signal output, phase -    Audio 21  EAR+  AO Earphone signal output, phase +    Audio 22  MIC-  AI Mic.signal input; phase-    Audio 24  MIC+  AI Mic.signal input; phase+    Audio 23  AGND  -  Analog Ground    - SIM card interface 9  SIMVCC  -  External SIM signal – Power supply for the SIM    1,8 / 3V 10  SIMRST  O  External SIM signal – Reset    1,8 / 3V 11  SIMCLK  O  External SIM signal – Clock    1,8 / 3V 12  SIMIO  I/O  External SIM signal – Data I/O  4.7K Pull up  1,8 / 3V X All GPI0 can be  programmed SIMIN  I  Presence SIM input (See para 11.9)    CMOS 2.8V Trace 44  RXD_AUX  I  Auxiliary UART (RX Data)    CMOS 2.8V 45  TXD_AUX  O  Auxiliary UART (TX Data)    CMOS 2.8V Prog. / Data + HW Flow Control 1  C109/DCD/GPO  O Output for Data carrier detect signal (DCD) to DTE  / GP output   CMOS 2.8V 2  C125/RING/GPO  O Output for Ring indicator signal (RI) to DTE / GP output   CMOS 2.8V 3  C107/DSR/GPO  O Output for Data set ready signal (DSR) to DTE / GP output   CMOS 2.8V 4  C108/DTR/GPI  I Input for Data terminal ready signal (DTR) from DTE / GP input   CMOS 2.8V 5  C105/RTS/GPI  I Input for Request to send signal (RTS) from DTE / GP input   CMOS 2.8V 6  C106/CTS/GPO  O Output for Clear to send signal (CTS) to DTE / GP output   CMOS 2.8V 7  C103/TXD  I  Serial data input (TXD) from DTE    CMOS 2.8V 8  C104/RXD  O  Serial data output to DTE    CMOS 2.8V DAC and ADC 13  ADC_IN1  AI Analog/Digital converter input    A/D 14  ADC_IN2  AI Analog/Digital converter input    A/D 15  DAC_OUT  AO Digital/Analog converter output    D/A
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 14 of 79  Pad  Signal  I/O  Function  Note  Type Miscellaneous Functions 30  VRTC  AO VRTC Backup     Power 47  RESET*  I  Reset input    CMOS 1.8V 43  V_AUX / PWRMON  O  2.8V stabilized output Imax=100mA / Power ON monitor    Power Out 2.8V 34  Antenna  O  Antenna output – 50 Ω    RF GPIO 42  GPIO_01 / DVI_WA0 I/O GPIO01 Configurable GPIO  / Digital Audio Interface (WA0)    CMOS 2.8V 41  GPIO_02 / JDR / DVI_RX I/O GPIO02  Configurable GPIO / Jammer Detect Report  / Digital Audio Interface (RX)   CMOS 2.8V 40  GPIO_03 / DVI_TX I/O GPIO03 Configurable GPIO  / Digital Audio Interface (TX)    CMOS 2.8V 39  GPIO_04 / TX Disable  / DVI_CLK I/O GPIO04 Configurable GPIO / TX Disable input / Digital Audio Interface (CLK)   CMOS 2.8V 29  GPIO_05 / RFTXMON I/O GPIO05 Configurable GPIO  / Transmitter ON monitor    CMOS 2.8V 28  GPIO_06 / ALARM  I/O GPIO06 Configurable GPIO  / ALARM    CMOS 2.8V 27  GPIO_07 / BUZZER I/O GPIO07 Configurable GPIO  / Buzzer    CMOS 2.8V 26  GPIO_08 / STAT_LED I/O GPIO08 Configurable GPIO  / STAT LED    CMOS 2.8V Power Supply 38  VBATT  -  Main power supply (Baseband)    Power 37  VBATT_PA  -  Main power supply (Radio PA)    Power  23  AGND  -  AF Signal Ground (see audio section)    AF Signal 32  GND  -  Ground    Power 33  GND  -  Ground    Power 35  GND  -  Ground    Power 36  GND  -  Ground    Power 46  GND  -  Ground    Power RESERVED 48    -       16    -       17    -       18    -       19    -       25    -       31    -         WARNING: Reserved pins must not be connected.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 15 of 79    NOTE: If not used, almost all pins should be left disconnected. The only exceptions are the following pins:  pin signal 38, 37  VBATT & VBATT_PA 32, 33, 35, 36, 46  GND 23  AGND 7  TXD 8  RXD 5  RTS 43  V_AUX / PWRMON 47  RESET* 45  TXD_AUX 44  RXD_AUX
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 16 of 79  4.2. Pin Layout   TOP VIEW   NOTE: The pin defined as NC/RFU has to be considered RESERVED and don’t connect on any pin in the application.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 17 of 79  5.  Hardware Commands 5.1.  Auto-Turning ON the GL865 To Auto-turn on  the  GL865,  the  power  supply must  be  applied  on the  power  pins  VBATT  and  VBATT_PA,  after  1000  m-seconds,  the V_AUX / PWRMON pin will be at the high logic level and the module can be consider fully operating.  When the power supply voltage is lower than 3.4V, after 4000 m-seconds, the V_AUX  /  PWRMON  pin  will  be  at  the high  logic  level and the module can be consider fully operating.  The following flow chart shows the proper turn on procedure:       Modem ON Proc. PWR supply = ON? Y Delay 1s - 4s for Low Voltage Operating Y Modem Reset Proc. AT init sequence. N Start AT CMD. N PWMON = ON? Y PWMON = ON? Delay 300mS Enter AT<CR> AT answer in 1second ? N Y N Delay 1s
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 18 of 79  NOTE: The power supply on the pins VBATT and VBATT_PA must be applied at the same time or for the special application in the first apply the VBATT_PA and in second time apply VBATT, never vice versa in this case can be damage the unit.   NOTE: In order to avoid a back powering effect it is recommended to avoid having any HIGH logic level signal applied to the digital pins of the GL865 when the module is powered OFF or during an ON/OFF transition.  A flow chart showing the AT command managing procedure is displayed below:     Modem ON Proc. Disconnect PWR supply AT init sequence. Delay 300mS Enter AT<CR> AT answer in 1second ? Y N Start AT CMD.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 19 of 79  5.2. Turning OFF the GL865 Turning off of the device can be done in two ways: • General turn OFF • Processor turn OFF General  turn  OFF  –  disconnect  the  power  supply  from  the  both power pins VBATT and VBATT_PA at the same time. In this case all parts of the module are in OFF condition, any power consumption is present. Processor  turn  OFF  –  disconnect  the  power  supply  only  from the power  pin  VBATT,  the  power  pin  VBATT_PA  can  be  connected  to power supply, in this case a low, about 30uA, power consumption is present  Before any of both OFF procedure will be applied, the AT#SYSHALT AT  command  must  be  send  (see  AT  Commands  Reference  Guide, 80000ST10025a), after the OK response message, check the V_AUX / PWRMON  pin,  when  the  logic  level  is  low  the  module  can  be consider  fully  not  operating  and  at  this  moment  is  possible disconnect the Power Supply The following flow chart shows the proper turnoff procedure:
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 20 of 79    TIP:  To check if the device has been powered off, the hardware line PWRMON must be monitored. The device is powered off when PWRMON goes low.  NOTE: In order to avoid a back powering effect it is recommended to avoid having any HIGH logic level signal applied to the digital pins of the GL865 when the module is powered OFF or during an ON/OFF transition. Modem OFF Proc. PWRMON = OFF? Place AT command AT#SYSHALT N Disconnect PWR supply Y Disconnect PWR supply Wait  PWRMON =OFF or  15s timeout Modem ON Proc. Delay 1.5s
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 21 of 79  5.3. Resetting the GL865 5.3.1. Hardware Unconditional restart  WARNING: 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.  To unconditionally reboot the GL865, the pad RESET* must be tied low for at least 200 milliseconds and then released.  NOTE:  Do not 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 GL865 power regulator and improper functioning of the module. The line RESET* must be connected only in open collector configuration; the transistor must be connected as close as possible to the RESET* pin. TIP: The unconditional hardware restart must always be implemented on the boards and the software must use it as an emergency exit procedure.  A simple circuit to do it is:
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 22 of 79  In  the  following  flow  chart  is  detailed  the  proper  restart procedure:      NOTE: In order to avoid a back powering effect it is recommended to avoid having any HIGH logic level signal applied to the digital pins of the GL865 when the module is powered OFF or during an ON/OFF transition. Modem Reset Proc. Reset = LOW Delay 200ms Reset = HIGH PWRMON = OFF   Delay 1s  Start AT CMD. Modem ON Proc. Delay 1,5s Y N Disconnect  PWR supply
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 23 of 79  6.  Power Supply The power supply circuitry and board layout are a very 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 The external power supply must be connected to VBATT & VBATT_PA signals and must fulfill the following requirements:  POWER SUPPLY Nominal Supply Voltage 3.8 V Normal Operating Voltage Range 3.4 V÷ 4.20 V Extended Operating Voltage Range 3.22 V÷ 4.50 V  NOTE: The Operating Voltage Range MUST never be exceeded; care must be taken in order to fulfil min/max voltage requirement.  NOTE: Overshoot voltage (regarding MAX Extended Operating Voltage) and drop in voltage (regarding MIN Extended Operating Voltage) MUST never be exceeded;  The “Extended Operating Voltage Range” can be used only with completely assumption and application of the HW User guide suggestions.   NOTE: When the power supply voltage is lower than 3.4V, after 4000 m-seconds, the V_AUX / PWRMON pin will be at the high logic level and the module can be consider fully operating. See para 5.1.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 24 of 79   6.2. Power Consumption The GL865 power consumptions are:   GL 865 Mode  Average (mA)  Mode description SWITCHED OFF  Module power supplied only on VBATT_PA pin, the VBATT pin is not power supplied. Switched Off  <5uA Switched Off with AT#SYSHALT <650uA Module power supplied on VBATT_PA pin and VBATT pin, the at command AT#SYSHALT is applied. IDLE mode AT+CFUN=1 21,0 Normal mode: full functionality of the module AT+CFUN=4 18,0 Disabled TX and RX; module is not registered on the network AT+CFUN=0 or =5  3,9 Paging Multiframe 2 2,5 Paging Multiframe 3 2,4 Paging Multiframe 4 1,5 Paging Multiframe 9 CSD TX and RX mode GSM VOICE CALL GSM900 CSD PL5 230 DCS1800 CSD PL0 180 GPRS (class 8) 1TX  GPRS Sending data mode GSM900 PL5 225 DCS1800 PL0 175 GPRS (class 10) 2TX  GPRS Sending data mode GSM900 PL5  360 DCS1800 PL0  300  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,  and  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.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 25 of 79    NOTE: 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. 6.3. 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. 6.3.1.  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  6.3.1.1.  + 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 GL865, 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 GL865 from power polarity inversion.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 26 of 79  An example of linear regulator with 5V input is:                     6.3.1.2.  + 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 GL865. When  using  a  switching  regulator,  a  500kHz  or  more  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.  In  any  case  the  frequency  and  Switching  design  selection  is related to the application to  be  developed  due  to  the fact the switching frequency could also generate EMC interferences. 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.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 27 of 79  A protection diode should be inserted close to the power input, in  order to  save  the  GL865  from  power polarity  inversion. This can be the same diode as for spike protection.  An example of switching regulator with 12V input is in the below schematic (split in 2 parts):                             6.3.1.3.  Battery Source Power Supply Design Guidelines
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 28 of 79  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 GL865 module.  WARNING: The three cells Ni/Cd or Ni/MH 3,6 V Nom. battery types or 4V PB types MUST NOT BE USED DIRECTLY since their maximum voltage can rise over the absolute maximum voltage for the GL865 and damage it.  NOTE: DON'T USE any Ni-Cd, Ni-MH, and Pb battery types directly connected with GL865. Their use can lead to overvoltage on the GL865 and damage it. USE ONLY 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  GL865  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.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 29 of 79  6.3.2. Thermal Design Guidelines The thermal design for the power supply heat sink should be done with the following specifications: See para 7.2 Power Consumption  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.  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.  For the  heat  generated by  the GL865, you can  consider it  to  be during  transmission  1W  max  during  CSD/VOICE  calls  and  2W  max during class10 GPRS upload.  This generated heat will be mostly conducted to the ground plane under  the  GL865;  you  must  ensure  that  your  application  can dissipate it.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 30 of 79  6.3.3. 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 GL865  power  input  pads  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 GL865 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 GL865, then this noise is not so disturbing and power supply layout design can be more forgiving. The  PCB  traces  to  the  GL865  and  the  Bypass  capacitor  must  be wide  enough  to  ensure  no  significant  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. 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.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 31 of 79  The power supply input cables should be kept separate from noise sensitive lines such as microphone/earphone cables.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 32 of 79  7.  Antenna The  antenna  connection  and  board  layout  design  are  the  most important  aspect  in  the  full  product  design  as  they  strongly affect  the  product  overall  performances,  hence  read  carefully and  follow  the  requirements  and  the  guidelines  for  a  proper design. 7.1.  GSM Antenna Requirements As  suggested  on  the  Product  Description  the  antenna  and  antenna transmission  line  on  PCB  for  a  Telit  GL865  device  shall  fulfil  the following requirements:  ANTENNA REQUIREMENTS                                                          QUAD  DUAL Frequency range 824-894 MHz GSM850 band 880-960 MHz GSM900 band  1710-1885MHz DCS1800 band  1850-1990MHz PCS1900 band 880-960 MHz GSM900 band 1710-1885MHz  MHz DCS1800 band Gain 1.4dBi @ GSM900 and 3dBi @ DCS1800 1.4dBi @ GSM850 and 3dBi @ PCS1900 1.4dBi @ GSM900 and 3dBi @ DCS1800 Impedance  50 Ohm  50 Ohm Input power  > 2 W   > 2 W  VSWR absolute max ≤  10:1 (limit to avoid permanent damage) ≤  10:1 (limit to avoid permanent damage) VSWR recommended  ≤   2:1 (limit to fulfil all regulatory requirements) ≤   2:1 (limit to fulfil all regulatory requirements)  When using the GL865, since there's no antenna connector on the module, the  antenna  must  be connected  to the  GL865  antenna  pad (pin 34) by means of a transmission line implemented on the PCB.  In the case the antenna is not directly connected at the antenna pad of the GL865, then a PCB line is needed in order to connect with it or with its connector.    This  line  of  transmission  shall  fulfill  the  following requirements:  ANTENNA LINE ON PCB REQUIREMENTS Characteristic Impedance 50 Ohm Max Attenuation  0,3 dB
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 33 of 79  Coupling with other signals shall be avoided Cold End (Ground Plane) of antenna shall be equipotential to the GL865 ground pins  7.2.  GSM Antenna - PCB line Guidelines  Make sure  that  the  transmission line’s characteristic impedance is 50Ω; Keep the  length of line  on the PCB  as  short as possible,  since the antenna line loss shall be less than about 0,3 dB; Line  geometry  should  have  uniform  characteristics,  constant cross section, avoid meanders and abrupt curves; Any kind of suitable geometry / structure (Microstrip, Stripline, Coplanar,  Grounded  Coplanar  Waveguide...)  can  be  used  for implementing the printed transmission line afferent the antenna; If a  Ground  plane  is  required  in  line  geometry, that  plane  has to be continuous and sufficiently extended, so the geometry can be as similar as possible to the related canonical model; Keep, if  possible, at least  one layer of  the PCB used  only for the  Ground  plane.  If  possible,  use  this  layer  as  reference Ground plane for the transmission line; It is wise to surround (on both sides) the PCB transmission line with  Ground,  avoid  having  other  signal  tracks  facing  directly the antenna line track.  Avoid crossing any un-shielded transmission  line  footprint  with other signal tracks on different layers; The  ground  surrounding  the  antenna  line  on  PCB  has  to  be strictly  connected  to  the  main  Ground  Plane  by  means  of  via holes (once per 2mm at least), placed close to the ground edges facing line track; Place  EM  noisy  devices  as  far  as  possible  from  GL865  antenna line; Keep  the  antenna  line  far  away  from  the  GL865  power  supply lines; If  EM  noisy  devices  are  present  on  the  PCB  hosting  the  GL865, such  as  fast  switching  ICs,  take  care  of  the  shielding  of  the antenna line by burying it inside the layers of PCB and surround it with Ground planes, or shield it with a metal frame cover. If EM noisy devices are not present around the line, the use of geometries like Microstrip or Grounded Coplanar Waveguide has to be  preferred,  since  they  typically  ensure  less  attenuation  if compared to a Stripline having same length;
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 34 of 79  7.3. PCB Guidelines in case of FCC certification  In the case FCC certification is required for an application using GL865, according to FCC KDB 996369 for modular approval requirements, the transmission line has to be similar to that implemented on GL865 interface board and described in the following chapter. 7.3.1. Transmission line design  During the design of the GL865 interface board, the placement of components has been chosen properly, in order to keep the line length as short as possible, thus leading to lowest power losses possible. A Grounded Coplanar Waveguide (G-CPW) line has been chosen, since this kind of transmission line ensures good impedance control and can be implemented in an outer PCB layer as needed in this case. A SMA female connector has been used to feed the line. The interface board is realized on a FR4, 4-layers PCB. Substrate material is characterized by relative permittivity εr = 4.6 ± 0.4 @ 1 GHz, TanD= 0.019 ÷ 0.026 @ 1 GHz. A characteristic impedance of nearly 50 Ω is achieved using trace width = 1.1 mm, clearance from coplanar ground plane = 0.3 mm each side. The line uses reference ground plane on layer 3, while copper is removed from layer 2 underneath the line. Height of trace above ground plane is 1.335 mm. Calculated characteristic impedance is 51.6 Ω, estimated line loss is less than 0.1 dB. The line geometry is shown below:                    0.3 mm0.035 mm0.3 mm6.2 mmFR40.035 mm0.035 mm1.335 mm0.2 mm1.1 mmL3L2L11.1 mm
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 35 of 79   7.3.2. Transmission line measurements  HP8753E VNA (Full-2-port calibration) has been used in this measurement session. A calibrated coaxial cable has been soldered at the pad corresponding to GL865 RF output; a SMA connector has been soldered to the board in order to characterize the losses of the transmission line including the connector itself. During Return Loss / impedance measurements, the transmission line has been terminated to 50 Ω load. Return Loss plot of line under test is shown below:
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 36 of 79  Line input impedance (in Smith Chart format, once the line has been terminated to 50 Ω load) is shown in the following figure:                       Insertion Loss of G-CPW line plus SMA connector is shown below:
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 37 of 79       7.4. GSM Antenna - Installation Guidelines Install the antenna in a place covered by the GSM signal. Antenna shall not be installed inside metal cases  Antenna  shall  be  installed  also  according  Antenna  manufacturer instructions.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 38 of 79  8.  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 GL865 interface circuits:  Absolute Maximum Ratings -Not Functional Parameter  Min  Max Input level on any digital pin (CMOS 2.8) when on -0.3V +3.1V Input level on any digital pin (CMOS 1.8) when on -0.3V +2.1V 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  2.1V  3.1V Input low level  0V  0.5V Output high level  2.2V  3.1V Output low level  0V  0.35V  For 1.8V signals: Operating Range - Interface levels (1.8V CMOS) Level  Min  Max Input high level  1.6V  2.0V Input low level  0V  0.4V Output high level  1,65V  2.0V Output low level  0V  0.35V  Current characteristics Level  Typical Output Current  1mA Input Current  1uA
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 39 of 79  8.1. Reset signal  Signal  Function  I/O  pin RESET*  Phone reset I  47   RESET* is used to reset the GL865. Whenever this signal is pulled low, the  GL865 is reset.  When the device is  reset it stops any operation.  After  the  release  of  the  reset  GL865  is unconditionally  shut  down,  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 GL865. Use the ON/OFF procedure to perform this function.  Reset Signal Operating levels: Signal  Min  Max RESET* Input high  1.8V(NOTE1) 2.1V RESET* Input low  0V  0.2V  (NOTE1) 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.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 40 of 79
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 41 of 79  9.  Serial Ports The  serial  port  on  the  GL865  is  the  core  of  the  interface between the module and OEM hardware.  2 serial ports are available on the module: MODEM SERIAL PORT 1 (MAIN)  for AT commands and Data MODEM SERIAL PORT 2 (AUX)  for AT commands or Debug   9.1. MODEM SERIAL PORT 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  GL865  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 GL865 UART are the CMOS levels:      Absolute Maximum Ratings -Not Functional Parameter  Min  Max Input level on any digital pad when on -0.3V  +3.1V Input voltage on analog pads when on -0.3V  +3.1V            Operating Range - Interface levels (2.8V CMOS) Level  Min  Max Input high level    VIH 2.1V  3.1 V Input low level     VIL 0V  0.5V Output high level VOH 2.2V  3.1V Output low level  VOL 0V  0.35V
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 42 of 79         The signals of the GL865 serial port are:  RS232 Pin Number Signal  GL865 Pad Number Name  Usage 1  DCD - dcd_uart 1  Data Carrier Detect Output from the GL865 that indicates the carrier presence 2  RXD - tx_uart  8 Transmit line *see Note Output transmit line of GL865 UART 3  TXD - rx_uart  7  Receive line *see Note Input receive of the GL865 UART 4  DTR - dtr_uart 4  Data Terminal Ready Input to the GL865 that controls the DTE READY condition 5  GND  32, 33, 35, 36, 46 Ground  ground 6  DSR - dsr_uart 3  Data Set Ready Output from the GL865 that indicates the module is ready 7  RTS -rts_uart  5  Request to Send Input to the GL865 that controls the Hardware flow control 8  CTS - cts_uart 6  Clear to Send Output from the GL865 that controls the Hardware flow control 9  RI - ri_uart  2  Ring Indicator Output from the GL865 that indicates the incoming call condition  NOTE: According to V.24, RX/TX signal names are referred to the application side, therefore on the GL865 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  GL865 serial port and viceversa for RX.  NOTE: 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.  NOTE:
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 43 of 79  In order to avoid a back powering effect it is recommended to avoid having any HIGH logic level signal applied to the digital pins of the GE865 when the module is powered off or during an ON/OFF transition. 9.2. RS232 level translation In  order  to  interface  the  GL865  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 0/2.8V 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  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  drivers  and receivers 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 0-2.8V UART to the RS232 level. The receiver is the translator from the RS232 level to 0-2.8V UART. In order to translate the whole set of control lines of the UART you will need: • 5 drivers • 3 receivers   NOTE: The digital input lines working at 2.8V CMOS have an absolute maximum input voltage of 3.0V; therefore the level translator IC shall not be powered by the +3.8V supply of the module. Instead, it must be powered from a +2.7V / +2.9V (dedicated) power supply. This is because in this way the level translator IC outputs on the module side (i.e. GL865 inputs) will work at +3.8V interface levels, damaging the module inputs.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 44 of 79
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 45 of 79  An example of level translation circuitry of this kind is:     The  example  is done with  a MAXIM  MAX3237 Transceiver  that  could accept supply voltages of 3V DC. Not exceeded with supply voltage higher  then  3.1VDC  because  this  is  the  higher  voltage  limit  of module’s inputs.  NOTE: In this case Vin has to be set with a value compatible with the logic levels of the module. (Max 3.1V DC)
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 46 of 79   Second solution could be done using a MAXIM transceiver (MAX218) In this case the compliance with RS232 (+-5V) is possible.                    Another  level adapting method could be done using a standard RS232 Transceiver (MAX3237EAI)  adding  some  resistors  to  adapt  the  levels  on  the GL865 Input lines.  NOTE: In this case has to be taken in account the length of the lines on the application to avoid problems in case of High-speed rates on RS232.  The  RS232  serial  port  lines  are  usually  connected  to  a  DB9 connector with the following layout: 9.3.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 47 of 79  9.4.  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.  For  example  a  possible translator circuit for a 5V TRANSMITTER/RECEIVER can be:     TIP: Note that the TC7SZ07AE has open drain output; therefore the resistor R2 is mandatory.   NOTE: The UART input line TXD (rx_uart) of the GL865 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.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 48 of 79  NOTE: The input lines working at 2.8VCMOS can be pulled-up with 47KΩ  In case of reprogramming of the module has to be considered the use of the RESET line to start correctly the activity. The preferable configuration is having an external supply for the buffer.   NOTE: In order to avoid a back powering effect it is recommended to avoid having any HIGH logic level signal applied to the digital pins of the GL865 when the module is powered OFF or during an ON/OFF transition.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 49 of 79  10.  Audio Section Overview The Base Band Chip of the GL865 provides one input for audio to be transmitted (Uplink), that can be connected directly to a microphone or an audio source. The bias for the microphone is already provided by the product; so the connection can be done in both following ways:  For more information refer to Telit document :   “ 80000NT10007a Audio Settings Application Note “.  MIC connection       TIP:   Since  the  J-FET  transistor  inside  the  microphone  acts as RF-detector-amplifier, ask vendor for a microphone with anti-EMI 1u 220n220n1K1K MIC/AF_IN+ MIC/AF_IN-AGNDMODULE -+INPUTADCVmicWire Or Ground Plane 1u220n220n 1K2.2K 1u ÷10uMODULE - + INPUTADC Vmic MIC/AF_IN+MIC/AF_IN- AGND Integral Ground Plane
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 50 of 79  capacitor (usually a 33pF or a 10pF capacitor placed across the output terminals inside the case).  LINE-IN connection      If  the  audio  source  is  not  a  mike  but  a  different  device,  the following connections can be done. Place a 1Kohm resistor to ground on the negative input, in order to  get  balanced  the  input;  than  connect  the  source  via  1uF capacitor, so the DC current is blocked. Since  the  input  is  differential,  the  common  mode  voltage  noise between  the  two  (different)  ground  is  rejected,  provided  that both AF_IN+ & AF_IN- are connected directly onto the source. 1u220n220n 1K1K 1u1uAF_IN+MIC/AF_IN+ MIC/AF_IN- AGND MODULE -+INPUTADCVmic AF_IN-1u220n220n 1K1K1u1uAF_IN+MIC/AF_IN+MIC/AF_IN-AGND MODULE  - + INPUTADC Vmic Remote_GND
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 51 of 79  EAR connection connection    The  audio  output  of  the  GL865  is  balanced,  this  is  helpful  to double  the  level  and  to  reject  common  mode  (click  and  pop  are common mode and therefore rejected). These  outputs  can  drive  directly  a  small  loudspeaker  with electrical impedance not lower than 8Ohm.    TIP:  in order to get the maximum audio level at a given output voltage  level  (dBspl/Vrms),  the  following  breaking  through procedure can be used. Have the loudspeaker as close as you can to the listener (this simplify also the echo cancelling); choose the  loudspeaker  with  the  higher  sensitivity  (dBspl  per  W); choose  loudspeakers  with  the  impedance  close  to  the  limit  (ex: 16 or 8 Ohm), in order to feed more power inside the transducer (it  increases  the  W/Vrms  ratio).  If  this  were  not  enough,  an external amplifier should be used.           EAR+EAR-MODULE  -+OUTPUT DAC
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 52 of 79  10.1. Electrical Characteristics 10.1.1. Input Lines  Microphone/Line-in path Line Type  Differential Coupling capacitor  ≥ 1µF Differential input resistance  1kΩ/2kΩ/2.2kΩ Levels To have 0dBm0 @1KHz (*) Differential input voltage AT#HFMICG=0    290mVrms AT#HFMICG=1  (+6dB)    145mVrms AT#HFMICG=2  (+12dB)    72mVrms AT#HFMICG=3  (+18dB)    36mVrms AT#HFMICG=4  (+24dB)    18mVrms AT#HFMICG=5  (+30dB)    9mVrms AT#HFMICG=6  (+36dB)    4.5mVrms AT#HFMICG=7  (+42dB)    2.25mVrms  (*)  0 dBm0 in the network are -3.14 dBfs   TIP:  The Electrect microphone is internally amplified by a J-Fet transistor, thus the sound is carried out as saturation drain current; this means that the norton equivalence has to be considered. The signal is converted to voltage on the 2.2KOhm resistance, from there on circuitry has to be routed in order to not pick up common mode noise; beware of the return path (ground).
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 53 of 79       10.1.2. Output Lines     EAR/Line-out Output Differential line coupling Direct connection (VDC=1.3÷1.6V) Single-ended line coupling    One EAR terminal connected via a DC-block capacitor, the other one left open output load resistance  ≥ 8 Ω internal output resistance 4 Ω (typ.) signal bandwidth  250÷3400Hz (@ -3dB with default filter) max. differential output voltage 1120mVpp @3.14dBm0 (*) differential output voltage 550mVrms @0dBm0 (*) volume increment  2dB per step volume steps  0..10  (*)  in default condition: AT+CLVL=10, AT#HFRECG=0  TIP : We suggest driving the load differentially; this kills all the common mode noises (click and pop, for example), the output swing will double (+6dB) and the big output coupling capacitor will be avoided. However if particular OEM application needs, also a Single Ended (S.E) circuitry can be implemented. The OEM circuitry shall be designed to reduce the common mode noise typically generated by the return path of the big currents. In order to get the maximum power output from the device, the resistance of the tracks has to be negligible in comparison to the load.  WARNING.  When in Single Ended configuration, the unused output line must be left open: if this constraint is not respected, the output stage will be damaged.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 54 of 79
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 55 of 79  11.  General Purpose I/O The  general  purpose  I/O  pads  can  be  configured to  act  in  three different ways:  • input • output • alternate function (internally controlled)  Input pads can only be read; they report the digital value (high or low) present on the pad at the read time . Output pads can only be written or queried and set the value of the pad output. An alternate function pad is internally controlled by the GL865 firmware and acts depending on the function implemented.    For Logic levels please refer to chapter 8.  The following table shows the available GPIO on the GL865.  Pin Signal I/O Function Type Input / output current Default State ON_OFF state State during Reset Note 42  GPIO_01 I/O Configurable GPIO CMOS 2.8V  1uA/1mA INPUT  0  0 Alternate function DVI_WA0   41  GPIO_02 I/O Configurable GPIO CMOS 2.8V  1uA/1mA INPUT  0  0 Alternate function  JDR and DVI_RX   40  GPIO_03 I/O Configurable GPIO CMOS 2.8V  1uA/1mA INPUT  0  0 Alternate function  DVI_TX   39  GPIO_04 I/O Configurable GPIO CMOS 2.8V  1uA/1mA INPUT  0  0 Alternate function TX disable and DVI_CLK   29  GPIO_05 I/O Configurable GPIO CMOS 2.8V  1uA/1mA INPUT  0  0 Alternate function RFTXMON 28  GPIO_06 I/O Configurable GPIO CMOS 2.8V  1uA/1mA INPUT  0  0 Alternate function ALARM 27  GPIO_07 I/O Configurable GPIO CMOS 2.8V  1uA/1mA INPUT  0  0 Alternate function BUZZER 26  GPIO_08 I/O Configurable GPIO CMOS 2.8V  1uA/1mA INPUT  0  0 Alternate function  STAT_LED
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 56 of 79      Also the UART ‘s control flow pins can be ubable as GPI/O.  Pin Signal I/O Function Type Input / output current Default State ON_OFF state State during Reset Note 1  GPO_A  O  Configurable GPO CMOS 2.8V  1uA/1mA INPUT  0  0 Alternate function C109/DCD 2  GPO_B  O  Configurable GPO CMOS 2.8V  1uA/1mA INPUT  0  0 Alternate function  C125/RING 3  GPO_C  O  Configurable GPO CMOS 2.8V  1uA/1mA INPUT  0  0 Alternate function  C107/DSR 4  GPI_E  I  Configurable GPI CMOS 2.8V  1uA/1mA INPUT  0  0 Alternate function  C108/DTR 5  GPI_F  I  Configurable GPI CMOS 2.8V  1uA/1mA INPUT  0  0 Alternate function C105/RTS 6  GPO_D  O  Configurable GPO CMOS 2.8V  1uA/1mA INPUT  0  0 Alternate function C106/CTS 11.1.  GPIO Logic levels  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 GL865 interface circuits:      Absolute Maximum Ratings -Not Functional Parameter  Min  Max Input level on any digital pin         when on (CMOS 2.8) -0.3V +3.1V Input level on any digital pin         when on (CMOS 1.8) -0.3V +2.1V Input voltage on analog pins        when on -0.3V +3.0V        Operating Range - Interface levels (2.8V CMOS) Level  Min  Max
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 57 of 79  Input high level 2.1V  3.1V Input low level  0V  0.5V Output high level  2.2V  3.1V Output low level 0V  0.35V   11.2. Using a GPIO Pad as INPUT The  GPIO  pads,  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 pad has interface levels different from the 2.8V CMOS, then it can be buffered with an open collector transistor with a 47K pull up to 2.8V.  NOTE: In order to avoid a back powering effect it is recommended to avoid having any HIGH logic level signal applied to the digital pins of the GL865 when the module is powered OFF or during an ON/OFF transition.  TIP: The V_AUX / PWRMON pin can be used for input pull up reference or/and for ON/OFF monitoring. 11.3.  Using a GPIO Pad as OUTPUT The GPIO pads, when used as outputs, can drive 2.8V CMOS digital devices  or  compatible  hardware.  When  set  as  outputs,  the  pads have  a  push-pull  output  and  therefore  the  pull-up  resistor  may be omitted. 11.4. Using the RFTXMON Output GPIO5 The GPIO5 pin, when configured as RFTXMON Output, is controlled by the GL865 module and will rise when the transmitter is active and fall after the transmitter activity is completed.  There are 2 different modes for this function: 1) Active during all the Call:
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 58 of 79  For example, if a call is started, the line will be HIGH during all the conversation and it will be again LOW after hanged up. The  line  rises  up  300ms  before  first  TX  burst  and  will  became again LOW from 500ms to 1s after last TX burst.  2) Active during all the TX activity: The GPIO is following the TX bursts  Please  refer  to  the  AT  User  interface  manual  for  additional information on how to enable this function.  11.5.  Using the Alarm Output GPIO6  The GPIO6 pad, when configured as Alarm Output, is controlled by the  GL865  module  and  will  rise  when  the  alarm  starts  and  fall after the issue of a dedicated AT command. This  output  can  be  used  to  controlling  microcontroller  or application at the alarm time. 11.6. Using the Buzzer Output GPIO7  The  GPIO7  pad,  when  configured  as  Buzzer  Output,  is  controlled by  the  GL865  module  and  will  drive  a  Buzzer  driver  with appropriate square waves. 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.  A sample interface scheme is included below to give you an idea of how to interface a Buzzer to the GPIO7:
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 59 of 79  TR1BCR141WTR2SMBT2907AR14,7KR21KD1D1N4148 C133pF +-+V buzzerGPIO7     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.   11.7. Magnetic Buzzer Concepts 1.1.1 Short Description  A  magnetic  Buzzer  is  a  sound-generating  device  with  a  coil located in the magnetic circuit consisting of a permanent magnet, an  iron  core,  a  high  permeable  metal  disk  and  a  vibrating diaphragm.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 60 of 79         Drawing of the Magnetic Buzzer.   The disk and diaphragm are attracted to the core by the magnetic field. When an oscillating signal is moved through the coil, it produces  a  fluctuating  magnetic  field  which  vibrates  the diaphragm at a frequency of the drive signal. Thus the sound is produced relative to the frequency applied.          Diaphragm movement. 11.7.1. Frequency Behaviour  The  frequency  behaviour  represents  the  effectiveness  of  the reproduction  of  the  applied  signals.  Because  performance  is related  to  a  square  driving  waveform  (whose  amplitude  varies from  0V  to  Vpp),  if  you modify  the  waveform (e.g.  from  square  to sinus) the frequency response will change. 11.7.2. Power Supply Influence  Applying  a  signal  whose  amplitude  is  different  from  that suggested by the manufacturer, the performance change following the  rule  “if  resonance  frequency  fo increases,  amplitude decreases”.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 61 of 79  Because  resonance  frequency  depends  on  acoustic  design,  by lowering  the  amplitude  of  the  driving  signal  the  response bandwidth tends to become narrow, and vice versa. Summarizing:        Vpp ↑  fo ↓         Vpp ↓  fo ↑   The  risk  is  that  the  fo  could  easily  fall  outside  of  new bandwidth;  consequently  the  SPL  could  be  much  lower  than  the expected.    11.7.3. Working Current Influence  In  the  component  data  sheet  you  will  find  the  value  of  MAX CURRENT:  this  represents  the  maximum  average  current  that  can flow  at  nominal  voltage  without  current  limitation.  In  other words it is not the peak current, which could be twice or three times  higher.  If  driving  circuitry  does  not  support  these  peak values,  the  SPL  will  never  reach  the  declared  level  or  the oscillations will stop.      11.8.  STAT LED Indication of network service availability  The STAT_LED pin status shows information on the network service availability and Call status. In the GL865 modules, the STAT_LED usually  needs  an  external  transistor  to  drive  an  external  LED. Therefore,  the  status  indicated  in  the  following  table  is reversed  with  respect  to  the  pin  status.  The  AT  command  to enable the function is AT#SLED=2, in order to save the function use the AT command AT#SLEDSAV, the AT command AT#SLED=0 disable the function and the functionality of GPIO8 can be used. (see AT Command user guide)           WARNING: It  is  very  important  to  respect  the  sense  of  the  applied voltage: never apply to the "-" pin a voltage more positive than the  "+"  pin:  if  this  happens,  the  diaphragm  vibrates  in  the opposite  direction  with  a  high  probability  to  be  expelled  from its physical position. This damages the device permanently.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 62 of 79  LED status  Device Status Permanently off  Device off Fast blinking (Period 1s, Ton 0,5s) Net search / Not registered / turning off Slow blinking (Period 3s, Ton 0,3s) Registered full service Permanently on  a call is active  NOTE: Don’t use the STAT LED function if the GPIO 8 function is enabled and vice versa!            A schematic example could be:                  11.9. SIMIN detect function  All  the  GPIO  pins  can  be  used  as  SIM  DETECT  input.  The  AT Command used to enable the function is:   #SIMINCFG– SIMIN pin configuration SELINT 2 AT#SIMINCFG = <GPIO_ pin>  The command enable the function on the general purpose I/O pin GPIO<pin>  Parameters: <GPIO_pin> - GPIO pin number;
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 63 of 79  supported range is from 1 to 8 (see chapter 11)  AT#SIMINCFG?  Read command reports the selected I/O pin in the format: #SIMINCFG: 1  AT#SIMINCFG =?  Test command reports supported range of values for parameters in the format: #SIMINCFG : (0 – 8)  0 = disabled    Use the AT command AT#SIMDET=2 to enable the SIMIN detection  Use the AT command AT&W0 and AT&P0 to store the SIMIN detection in the common profile (See AT Command user guide)   NOTE: Don’t use the SIM IN function on the same pin where the GPIO function is enabled and vice versa!
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 64 of 79   11.10.  RTC Bypass out The  VRTC  pin  brings  out  the  Real  Time  Clock  supply,  which  is separate from the rest of the digital part, allowing having only RTC going on when all the other parts of the device are off. To this  power output a backup battery can  be  added in  order  to increase  the  RTC  autonomy  during  power  off  of the  main  battery (power supply). NO Devices must be powered from this pin. 11.11. SIM Holder Implementation Please refer to the related User Guide (SIM Holder Design Guides, 80000NT10001a).
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 65 of 79  12.  DAC and ADC section 12.1. DAC Converter 12.1.1. Description The  GL865  provides  a  Digital  to  Analog  Converter.  The  signal (named DAC_OUT) is available on pin 15 of the GL865. The  on  board  DAC  is  a  10  bit  converter,  able  to  generate  a analogue value based a specific input in the range from 0 up to 1023. However, an external low-pass filter is necessary    Min  Max  Units Voltage range (filtered) 0  2,6  Volt Range  0  1023  Steps    The  precision  is  10  bits  so,  if  we  consider  that  the  maximum voltage  is  2V,  the  integrated  voltage  could  be  calculated  with the following formula:   Integrated output voltage = (2 *value) / 1023  DAC_OUT  line  must  be  integrated  (for  example  with  a  low  band pass filter) in order to obtain an analog voltage.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 66 of 79  12.1.2. Enabling DAC  An  AT command  is available to use the DAC function. The command is:     AT#DAC= [<enable> [, <value>]]  <value> - scale factor of the integrated output voltage (0..1023 - 10 bit precision) it must be present if  <enable>=1  Refer  to  SW  User  Guide  or  AT  Commands  Reference  Guide  for  the full description of this function.   NOTE: The DAC frequency is selected internally. D/A converter must not be used during POWERSAVING.    12.1.3. Low Pass Filter Example
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 67 of 79  12.2.   ADC Converter 12.2.1. Description  The on  board  A/D are  11-bit converter. They  are able to  read a voltage level  in the range of 0÷2 volts applied  on the ADC pin input, store and convert it into 11 bit word.    Min  Max  Units Input  Voltage range 0  2 Volt AD conversion -  11 bits Resolution -  < 1 mV  The GL865 module provides 2 Analog to Digital Converters.  The input lines are:  ADC_IN1   available on pin 13   ADC_IN2   available on pin 14  12.2.2.  Using ADC Converter  An  AT command is available to use the ADC function.  The command is AT#ADC=1,2  The read value is expressed in mV  Refer  to  SW  User  Guide  or  AT  Commands  Reference  Guide  for  the full description of this function.          12.3. Debug of the GL865 in production
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 68 of 79  To  test  and  debug  the  mounting  of  the  GL865,  we  strongly recommend  to  foreseen  test  pads  on  the  host  PCB,  in  order  to check  the  connection  between  the  GL865  itself  and  the application and to test the performance of the module connecting it  with  an  external  computer.  Depending  by  the  customer application,  these  pads  include,  but  are  not  limited  to  the following signals:                 pin  signal 38, 37  VBATT & VBATT_PA 32, 33, 35, 36, 46 GND 7  TXD 8  RXD 5  RTS 43 V_AUX / PWRMON 47  RESET* 45  TXD_AUX 44 RXD_AUX
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 69 of 79  13.   Mounting the GL865 on your Board 13.1. General The GL865  modules have  been  designed  in  order  to  be  compliant with a standard lead-free SMT process. 13.2. Module finishing & dimensions            Lead-free Alloy: Surface finishing Ni/Au for all solder pads Pin 1 Bottom View
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 70 of 79   13.3. Recommended foot print for the application                              In order to easily rework the GE865 is suggested to consider on the application a 1.5 mm placement inhibit area around the module. It is also suggested, as common rule for an SMT component, to avoid having a mechanical part of the application in direct contact with the module.  NOTE: In the customer application, the region under WIRING INHIBIT (see figure) must be clear from signal or ground paths. Top View
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 71 of 79   13.4. Solder paste   Lead free Solder paste  Sn/Ag/Cu  We recommend to use only “no clean” solder paste in order to avoid the cleaning of the modules after assembly  13.4.1. GL865 Solder reflow  The following is the recommended solder reflow profile
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 72 of 79      Profile Feature  Pb-Free Assembly Average  ramp-up  rate  (TL to TP) 3°C/second max Preheat – Temperature Min (Tsmin) – Temperature Max (Tsmax) – Time (min to max) (ts)  150°C 200°C 60-180 seconds Tsmax to TL – Ramp-up Rate  3°C/second max Time maintained above: – Temperature (TL) – Time (tL)  217°C 60-150 seconds Peak Temperature (Tp) 245 +0/-5°C Time within 5°C of actual Peak Temperature (tp) 10-30 seconds  Ramp-down Rate 6°C/second max. Time  25°C  to  Peak Temperature 8 minutes max.    NOTE: All temperatures refer to topside of the package, measured on the package body surface    WARNING: The GL865 module withstands one reflow process only.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 73 of 79  14.  Packing system  The GL865 modules are packaged on trays of 20 pieces each. This is especially suitable for the GL865 according to SMT processes for pick & place movement requirements.                               NOTE: All temperatures refer to topside of the package, measured on the package body surface    WARNING: These trays can withstand at the maximum temperature of 65° C.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 74 of 79   14.1. Moisture sensibility  The  level of moisture  sensibility  of  GL865 is  “3”,  in  according with  standard  IPC/JEDEC  J-STD-020,  take  care  all  the  relatives requirements for using this kind of components.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 75 of 79  15.  Conformity Assessment Issues  The Telit GL865 Module has been assessed in order to satisfy the essential requirements of the R&TTE Directive 1999/05/EC (Radio Equipment & Telecommunications Terminal Equipments) to demonstrate the conformity against the harmonised standards with the final involvement of a Notified Body.  If the module is installed in conformance to the Telit installation manuals, no further evaluation under Article 3.2 of the R&TTE Directive and do not require further involvement of a R&TTE Directive Notified Body for the final product.  In all other cases, or if the manufacturer of the final product is in doubt, then the equipment integrating the radio module must be assessed against Article 3.2 of the R&TTE Directive.  In all cases the assessment of the final product must be made against the Essential requirements of the R&TTE Directive Articles 3.1(a) and (b), Safety and EMC respectively, and any relevant Article 3.3 requirements.  This Hardware User Guide contains all the information you may need for developing a product meeting the R&TTE Directive.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 76 of 79  16.  SAFETY RECOMMANDATIONS READ CAREFULLY   Be sure the use of this product is allowed in the country and in the  environment  required.  The  use  of  this  product  may  be dangerous and has to be avoided in the following areas:   Where  it  can  interfere  with  other  electronic  devices  in environments such as hospitals, airports, aircrafts, etc  Where there is risk of explosion such as gasoline stations, oil refineries, etc   It  is  responsibility  of  the  user  to  enforce  the  country regulation and the specific environment regulation.  Do  not  disassemble  the  product;  any  mark  of  tampering  will compromise the warranty validity.  We  recommend  following  the  instructions  of  the  hardware  user guides for a correct  wiring  of  the  product.  The  product  has to be supplied with a stabilized voltage source and the wiring has to be conforming to the security and fire prevention regulations.  The  product  has  to  be  handled  with  care,  avoiding  any  contact with  the  pins  because  electrostatic  discharges  may  damage  the product  itself.  Same  cautions  have  to  be  taken  for  the  SIM, checking carefully the instruction for its use. Do not insert or remove the SIM when the product is in power saving mode.  The  system  integrator  is  responsible  of  the  functioning  of  the final  product;  therefore,  care  has  to be  taken  to  the  external components  of  the  module,  as  well  as  of  any  project  or installation  issue,  because  the  risk  of  disturbing  the  GSM network  or  external  devices  or  having  impact  on  the  security. Should  there  be  any  doubt,  please  refer  to  the  technical documentation and the regulations in force.  Every  module  has  to  be  equipped  with  a  proper  antenna  with specific  characteristics.  The  antenna  has  to  be  installed  with care  in  order  to  avoid  any  interference  with  other  electronic devices  and  has  to  guarantee  a  minimum  distance  from  the  body (20  cm).  In  case  of  this  requirement  cannot  be  satisfied,  the system  integrator  has  to  assess  the  final  product  against  the SAR regulation.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 77 of 79    The  European  Community  provides  some  Directives  for  the electronic equipments introduced on the market. All the relevant information’s are available on the European Community website:  http://ec.europa.eu/enterprise/sectors/rtte/documents/    The  text  of  the  Directive  99/05  regarding  telecommunication equipments  is  available,  while  the  applicable  Directives  (Low Voltage and EMC) are available at:  http://ec.europa.eu/enterprise/sectors/electrical      FCC Regulatory Requirements This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation. RF Exposure: The antenna(s) used for this transmitter must be installed to provide a separation distance of at least 20 cm from all the persons and must not be co-located or operating in conjunction with any other antenna or transmitter. The system antenna(s) used for this module must not exceed 1,4dBi (850MHz) and 3.0dBi (1900MHz) for mobile and fixed or mobile operating configurations.   Users and installers must be provided with antenna installation instructions and transmitter operating conditions for satisfying RF exposure compliance.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 78 of 79   IC Regulatory Requirements This device complies with Industry Canada license-exempt RSS standard(s). Operation is subject to the following two conditions:  (1) this device may not cause interference, and  (2) this device must accept any interference, including interference that may cause undesired operation of the device.   Le présent appareil est conforme aux CNR d'Industrie Canada applicables aux appareils radio exempts de licence. L'exploitation est autorisée aux deux conditions suivantes :  (1) l'appareil ne doit pas produire de brouillage, et  (2) l'utilisateur de l'appareil doit accepter tout brouillage radioélectrique subi, même si le brouillage est susceptible d'en compromettre le fonctionnement.   Under Industry Canada regulations, this radio transmitter may only operate using an antenna of a type and maximum (or lesser) gain approved for the transmitter by Industry Canada. To reduce potential radio interference to other users, the antenna type and its gain should be so chosen that the equivalent isotropically radiated power (e.i.r.p.) is not more than that necessary for successful communication.   Conformément à la réglementation d'Industrie Canada, le présent émetteur radio peut fonctionner avec une antenne d'un type et d'un gain maximal (ou inférieur) approuvé pour l'émetteur par Industrie Canada. Dans le but de réduire les risques de brouillage radioélectrique à l'intention des autres utilisateurs, il faut choisir le type d'antenne et son gain de sorte que la puissance isotrope rayonnée équivalente (p.i.r.e.) ne dépasse pas l'intensité nécessaire à l'établissement d'une communication satisfaisante.   The GL865-QUAD has been designed to comply with safety requirements for exposure to radio waves (SAR) in accordance with RSS-102.   Please follow the instructions included in the user guide for product installation and use.
     GL865 Hardware User Guide     1vv0300910 Rev.1 – 2011-07-22       Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved    page 79 of 79  This radio transmitter GL865-QUAD has been approved by Industry Canada to operate with antennas with maximum permissible gain not exceeding 1,4dBi (850MHz) and 3.0dBi (1900MHz). Antenna types having a gain greater than the maximum gain indicated are strictly prohibited for use with this device.     Le GL865-QUAD a été conçu pour se conformer aux exigences de sécurité pour l'exposition aux ondes radio (SAR) en conformité avec RSS-102. S'il vous plaît suivez les instructions incluses dans le guide utilisateur pour l'installation du produit et son utilisation.  Cet émetteur radio (numéro de modèle) a été approuvé par Industrie Canada pour fonctionner avec des antennes avec un gain maximal admissible de 1.4 dBi (850MHz) et 3.0dBi (1900MHz). Types d'antenne ayant un gain supérieur au gain maximal indiqué est strictement interdit pour une utilisation avec cet appareil.

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