MC55/56 Hardware Interface Description
p
Confidential / Released
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tion
MC55/56
Siemens Cellular Engine
Version: 02.06
DocID: MC55/56_hd_v02.06
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Hardware Interface Descri
MC55/56 Hardware Interface Description
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Document Name:
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Date:
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MC55/56 Hardware Interface Description
02.06
October 29, 2004
MC55/56_hd_v02.06
Confidential / Released
General Notes
Product is deemed accepted by recipient and is provided without interface to recipient’s products. The
documentation and/or product are provided for testing, evaluation, integration and information
purposes. The documentation and/or product are provided on an “as is” basis only and may contain
deficiencies or inadequacies. The documentation and/or product are provided without warranty of any
kind, express or implied. To the maximum extent permitted by applicable law, Siemens further
disclaims all warranties, including without limitation any implied warranties of merchantability,
completeness, fitness for a particular purpose and non-infringement of third-party rights. The entire
risk arising out of the use or performance of the product and documentation remains with recipient.
This product is not intended for use in life support appliances, devices or systems where a malfunction
of the product can reasonably be expected to result in personal injury. Applications incorporating the
described product must be designed to be in accordance with the technical specifications provided in
these guidelines. Failure to comply with any of the required procedures can result in malfunctions or
serious discrepancies in results. Furthermore, all safety instructions regarding the use of mobile
technical systems, including GSM products, which also apply to cellular phones must be followed.
Siemens or its suppliers shall, regardless of any legal theory upon which the claim is based, not be
liable for any consequential, incidental, direct, indirect, punitive or other damages whatsoever
(including, without limitation, damages for loss of business profits, business interruption, loss of
business information or data, or other pecuniary loss) arising out the use of or inability to use the
documentation and/or product, even if Siemens has been advised of the possibility of such damages.
The foregoing limitations of liability shall not apply in case of mandatory liability, e.g. under the
German Product Liability Act, in case of intent, gross negligence, injury of life, body or health, or
breach of a condition which goes to the root of the contract. However, claims for damages arising from
a breach of a condition, which goes to the root of the contract, shall be limited to the foreseeable
damage, which is intrinsic to the contract, unless caused by intent or gross negligence or based on
liability for injury of life, body or health. The above provision does not imply a change on the burden of
proof to the detriment of the recipient. Subject to change without notice at any time. The interpretation
of this general note shall be governed and construed according to German law without reference to
any other substantive law.
Copyright
Transmittal, reproduction, dissemination and/or editing of this document as well as utilization of its
contents and communication thereof to others without express authorization are prohibited. Offenders
will be held liable for payment of damages. All rights created by patent grant or registration of a utility
model or design patent are reserved.
Copyright © Siemens AG 2004
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Contents
0 Document history..........................................................................................................7
1 Introduction ...................................................................................................................9
1.1 Related documents................................................................................................9
1.2 Terms and abbreviations .....................................................................................10
1.3 Type approval ......................................................................................................13
1.4 Safety precautions ...............................................................................................15
2 Product concept.......................................................................................................... 17
2.1 MC55/56 key features at a glance .......................................................................18
2.2 Circuit concept .....................................................................................................21
3 Application Interface...................................................................................................22
3.1 Operating modes .................................................................................................23
3.2 Power supply .......................................................................................................25
3.2.1 Power supply pins on the board-to-board connector .............................25
3.2.2 Minimizing power losses........................................................................26
3.2.3 Monitoring power supply........................................................................26
3.3 Power up / down scenarios..................................................................................27
3.3.1 Turn on MC55/56 ................................................................................... 27
3.3.1.1 Turn on MC55/56 using the ignition line /IGT (Power on) ..........28
3.3.1.2 Timing of the ignition process.....................................................29
3.3.1.3 Turn on MC55/56 using the POWER signal...............................30
3.3.1.4 Turn on MC55/56 using the RTC (Alarm mode).........................30
3.3.2 Turn off MC55/56 ................................................................................... 32
3.3.2.1 Turn off MC55/56 using AT command .......................................32
3.3.2.2 Emergency shutdown using /EMERGOFF pin ...........................33
3.3.3 Automatic shutdown...............................................................................34
3.3.3.1 Temperature dependent shutdown ............................................34
3.3.3.2 Temperature control during emergency call...............................35
3.3.3.3 Undervoltage shutdown if battery NTC is present......................35
3.3.3.4 Undervoltage shutdown if no battery NTC is present.................36
3.3.3.5 Overvoltage shutdown................................................................36
3.4 Automatic GPRS Multislot Class change.............................................................37
3.5 Charging control ..................................................................................................38
3.5.1 Battery pack characteristics...................................................................39
3.5.2 Implemented charging technique........................................................... 41
3.5.3 Operating modes during charging..........................................................42
3.5.4 Charger requirements ............................................................................ 43
3.6 Power saving .......................................................................................................44
3.6.1 No power saving (AT+CFUN=1) ............................................................44
3.6.2 NON-CYCLIC SLEEP mode (AT+CFUN=0)..........................................44
3.6.3 CYCLIC SLEEP mode (AT+CFUN=5, 6, 7, 8) .......................................44
3.6.4 CYCLIC SLEEP mode AT+CFUN=9 .....................................................45
3.6.5 Timing of the /CTS signal in CYCLIC SLEEP modes ............................45
3.6.6 Wake up MC55/56 from SLEEP mode ..................................................47
3.7 Summary of state transitions (except SLEEP mode)........................................... 49
3.8 RTC backup.........................................................................................................50
3.9 Serial interfaces ...................................................................................................51
3.9.1 Features supported on first and second serial interface........................52
3.10 Audio interfaces ...................................................................................................54
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3.10.1 Microphone circuit.................................................................................. 55
3.10.2 Speech processing ................................................................................56
3.10.3 DAI timing ..............................................................................................56
3.11 SIM interface........................................................................................................58
3.11.1 Requirements for using the CCIN pin ....................................................59
3.11.2 Design considerations for SIM card holder............................................60
3.12 Control signals .....................................................................................................61
3.12.1 Inputs .....................................................................................................61
3.12.2 Outputs ..................................................................................................62
3.12.2.1 Synchronization signal ..........................................................62
3.12.2.2 Using the SYNC pin to control a status LED.........................63
3.12.2.3 Behavior of the /RING0 line (ASC0 interface only) ...............65
4 Antenna interface........................................................................................................ 67
4.1 Antenna installation .............................................................................................67
4.1.1 Antenna pad...........................................................................................69
4.1.1.1 Suitable cable types ...................................................................69
4.1.2 Hirose antenna connector...................................................................... 70
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5 Electrical, reliability and radio characteristics.........................................................74
5.1 Absolute maximum ratings ..................................................................................74
5.2 Operating temperatures.......................................................................................74
5.3 Electrical specifications of the application interface.............................................75
5.4 Power supply ratings ...........................................................................................80
5.4.1 Current consumption during transmit burst............................................81
5.5 Electrical characteristics of the voiceband part....................................................86
5.5.1 Setting audio parameters by AT commands..........................................86
5.5.2 Audio programming model.....................................................................87
5.5.3 Characteristics of audio modes..............................................................88
5.5.4 Voiceband receive path .........................................................................89
5.5.5 Voiceband transmit path ........................................................................90
5.6 Air interface..........................................................................................................91
5.7 Electrostatic discharge.........................................................................................92
5.8 Reliability characteristics .....................................................................................93
6 Mechanics....................................................................................................................94
6.1 Mechanical dimensions of MC55/56....................................................................94
6.2 Mounting MC55/56 onto the application platform ................................................96
6.3 Board-to-board connector....................................................................................97
6.3.1 Mechanical dimensions of the Hirose DF12 connector..........................98
6.3.2 Adapter cabling......................................................................................98
7 Reference Approval ....................................................................................................99
7.1 Reference Equipment for Type Approval.............................................................99
7.2 Compliance with FCC Rules and Regulations (MC55 only) ..............................100
7.3 Compliance with FCC Rules and Regulations (MC56 only) ..............................101
8 Design example.........................................................................................................102
9 List of parts and accessories...................................................................................104
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Figures
Figure 1: MC55/56 block diagram .......................................................................................... 21
Figure 2: Power supply limits during transmit burst................................................................ 26
Figure 3: Power-on by ignition signal ..................................................................................... 28
Figure 4: Timing of power-on process if VDDLP is not used.................................................. 29
Figure 5: Timing of power-on process if VDDLP is fed from external source......................... 29
Figure 6: Deactivating GSM engine by /EMERGOFF signal.................................................. 33
Figure 7: Schematic of approved charging transistor, trickle charging and ESD protection ..38
Figure 8: Battery pack circuit diagram....................................................................................39
Figure 9: Charging process .................................................................................................... 41
Figure 10: Timing of /CTS signal (example for a 2.12 s paging cycle)................................... 46
Figure 11: Beginning of power saving if CFUN=5 or 7........................................................... 46
Figure 12: RTC supply from capacitor.................................................................................... 50
Figure 13: RTC supply from rechargeable battery ................................................................. 50
Figure 14: RTC supply from non-chargeable battery ............................................................. 50
Figure 15: Serial interfaces .................................................................................................... 51
Figure 16: Audio block diagram.............................................................................................. 54
Figure 17: Schematic of microphone inputs ...........................................................................55
Figure 18: DAI timing on transmit path................................................................................... 57
Figure 19: DAI timing on receive path ....................................................................................57
Figure 20: SIM card holder of DSB45 Support Box................................................................ 60
Figure 21: Pin numbers of Molex SIM card holder on DSB45 Support Box........................... 60
Figure 22: SYNC signal during transmit burst ........................................................................62
Figure 23: LED Circuit (Example)........................................................................................... 64
Figure 24: Incoming voice call................................................................................................65
Figure 25: Incoming data call ................................................................................................. 65
Figure 26: URC transmission ................................................................................................. 65
Figure 27: U.FL-R-SMT connector .........................................................................................67
Figure 28: Antenna pad and GND plane ................................................................................67
Figure 29: Never use antenna connector and antenna pad at the same time .......................68
Figure 30: Restricted area around antenna pad..................................................................... 68
Figure 31: Mechanical dimensions of U.FL-R-SMT connector............................................... 70
Figure 32: U.FL-R-SMT connector with U.FL-LP-040 plug .................................................... 71
Figure 33: U.FL-R-SMT connector with U.FL-LP-066 plug .................................................... 71
Figure 34: Specifications of U.FL-LP-(V)-040(01) plug .......................................................... 72
Figure 35: Pin assignment (top view on MC55/56) ................................................................75
Figure 36: Typical current consumption vs. power control level............................................. 84
Figure 37: Typical current consumption vs. return loss.......................................................... 85
Figure 38: Audio programming model ....................................................................................87
Figure 39: MC55/56 – top view ..............................................................................................94
Figure 40: MC55/56 bottom view ...........................................................................................94
Figure 41: Mechanical dimensions of MC55/56 ..................................................................... 95
Figure 42: Mounting holes on MC55/56 ................................................................................. 96
Figure 43: Hirose DF12C receptacle on MC55/56 ................................................................. 97
Figure 44: Header Hirose DF12 series................................................................................... 97
Figure 45: Mechanical dimensions of Hirose DF12 connector............................................... 98
Figure 46: Reference equipment for approval........................................................................ 99
Figure 47: Schematic diagram of MC55/56 sample application ...........................................103
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Tables
Table 1: MC55/56 key features .............................................................................................. 18
Table 2: Coding schemes and maximum net data rates over air interface ............................ 20
Table 3: Overview of operating modes................................................................................... 23
Table 4: Power supply pins of board-to-board connector....................................................... 25
Table 5: AT commands available in Alarm mode................................................................... 30
Table 6: Temperature dependent behaviour ..........................................................................35
Table 7: Bill of material for external charging circuit............................................................... 38
Table 8: Specifications of recommended battery pack........................................................... 40
Table 9: Comparison Charge-only and Charge mode............................................................ 42
Table 10: AT commands available in Charge-only mode....................................................... 43
Table 11: Wake-up events in NON-CYCLIC and CYCLIC SLEEP modes.............................47
Table 12: State transitions of MC55/56 (except SLEEP mode) .............................................49
Table 13: DCE-DTE wiring of 1st serial interface................................................................... 52
Table 14: DCE-DTE wiring of 2nd serial interface.................................................................. 53
Table 15: Signals of the SIM interface (board-to-board connector) .......................................58
Table 16: Pin assignment of Molex SIM card holder on DSB45 Support Box........................ 60
Table 17: Input control signals of the MC55/56 module ......................................................... 61
Table 18: Coding of the status LED .......................................................................................63
Table 19: MC55/56 ring signal ...............................................................................................66
Table 20: Return loss .............................................................................................................67
Table 21: Product specifications of U.FL-R-SMT connector .................................................. 70
Table 22: Material and finish of U.FL-R-SMT connector and recommended plugs ...............71
Table 23: Ordering information for Hirose U.FL Series ..........................................................73
Table 24: Absolute maximum ratings .....................................................................................74
Table 25: Operating temperatures .........................................................................................74
Table 26: Electrical description of application interface .........................................................76
Table 27: Power supply ratings ..............................................................................................80
Table 28: Audio parameters adjustable by AT command ......................................................86
Table 29: Voiceband characteristics (typical)......................................................................... 88
Table 30: Voiceband receive path..........................................................................................89
Table 31: Voiceband transmit path......................................................................................... 90
Table 32: Air Interface ............................................................................................................ 91
Table 33: Measured electrostatic values................................................................................92
Table 34: Summary of reliability test conditions .....................................................................93
Table 35: Ordering information DF12 series .......................................................................... 97
Table 36: Electrical and mechanical characteristics of the Hirose DF12C connector ............ 97
Table 37: List of parts and accessories................................................................................ 104
Table 38: Molex sales contacts (subject to change) ............................................................105
Table 39: Hirose sales contacts (subject to change)............................................................105
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0 Document history
Preceding document: "MC55/56 Hardware Interface Description" Version 01.95
New document: "MC55/56 Hardware Interface Description" Version 02.06
Chapter What is new
5.5.3 Table 29: Sidetone gain at default settings for audio mode 5 and 6 set to - dB
9 Added new Siemens ordering numbers
Preceding document: "MC55/56 Hardware Interface Description" Version 01.05
New document: "MC55/56 Hardware Interface Description" Version 01.95
Chapter What is new
Throughout
document
1.3 Updated list of standards.
3.6, 3.12.2.2 More detailed description of status LED patterns.
3.5.1 Deleted vendor XWODA, battery pack can be obtained from various dealers.
3.11 Use CCGND line to shield CCIO line from CCCLK line.
5.2 Added footnote regarding heat sink.
5.4 Typical value for supply voltage has been changed from 4.1V to 4.2V
7.2, 7.3 Added IC: 267W-MC55 and IC: IC: 267W-MC56
8 New chapter: Design example
---- Deleted chapter “Maximum number of turn-on / turn-off cycles”
Maximum temperature has been changed from +65°C to +70°C.
Preceding document: "MC55/56 Hardware Interface Description" Version 01.03a
New document: "MC55/56 Hardware Interface Description" Version 01.05
Chapter Page What is new
1.3 13 Updated list of standards, MC55/56 now fully type approved and labeled with
CE mark
2.2 21 New block diagram.
3.2.2, 5.3 26, 75ff All statements relating to typical peak current now 1.6 A.
3.2.3 26 More detailed description of measuring periods for BATT+.
3.1, 3.5.3 23, 42 Removed remarks about charging during Alarm mode
3.3.1.4 30 Battery can be charged while module is in Alarm mode.
3.3.2.1 32 To keep /EMERGOFF pin and output pins of the serial interfaces from
floating when in high impedance state use additional resistors.
3.3.3.5 36 Modified description of overvoltage conditions.
3.5 38 Improved Figure 7.
3.6 44ff Added SLEEP mode 9, added information on RTS, revised Table 11.
3.12.2.3 65 Advantages of the /RING0 line usage explained in more detail.
4.1 67 Marked antenna pad and ground pad.
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Chapter Page What is new
4.1.2 70 Rated frequency changed from 3 to 6 GHz
5.3 75ff Table 26 - /EMERGOFF pin and output pins of serial interface: To keep
output pins from floating when in high impedance state use additional
resistors.
5.4 80
5.4.1 81 Revised introduction.
5.5.2 87 Improved Figure 38: Audio programming model
6.1 94
6.2 96 Revised mounting instructions.
9 104 Siemens ordering numbers added.
--- --- Deleted chapter on cooling elements.
Added test conditions for TALK and DATA GPRS: 50 Ω
New drawing in Figure 41. Corrected height from 2.8 ±0.2 to 2.95 ±0.2 mm
Preceding document: "MC55/56 Hardware Interface Description" Version 01.03
New document: "MC55/56 Hardware Interface Description" Version 01.03a
Chapter Page What is new
7.2, 7.3 100,
101
Corrected MC55 and MC56 specific information on FFC compliance
Preceding document: "MC55/56 Hardware Interface Description" Version 01.02
New document: "MC55/56 Hardware Interface Description" Version 01.03
Chapter Page What is new
1.3 13 Note on necessary FCC certification added.
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1 Introduction
This document describes the hardware interface of the Siemens MC55/56 module that
connects to the cellular device application and the air interface. As MC55/56 is intended to
integrate with a wide range of application platforms, all functional components are described
in great detail.
This guide therefore covers all information needed to design and set up cellular applications
incorporating the MC55/56 module. It aids rapid retrieval of interface specifications, electrical
and mechanical details and information on the requirements to be considered for integration
of further components.
1.1 Related documents
[1] MC55 AT Command, Version 02.06
MC56 AT Command, Version 02.06
[2] MC55/56 Release Notes, Version 02.06
[3] GPRS Startup User's Guide
[4] Remote-SAT User's Guide
[5] DSB45 Support Box - Evaluation Kit for Siemens Cellular Engines
[6] Application Note 23: Installing MC55/56 on DSB45
[7] Application Note 07: Li-Ion Batteries in GSM Applications
[8] Application Note 16: Upgrading MC5x Firmware, Version 06
[9] Application Note 14: Audio and Battery Parameter Download
[10] Application Note 02: Audio Interface Design
[11] Multiplexer User's Guide
[12] Multiplex Driver Developer’s Guide for Windows 2000 and Windows XP
[13] Multiplex Driver Installation Guide for Windows 2000 and Windows XP
[14] Application Note 22: Using TTY / CTM equipment
[15] Application Note 24: Application Developer’s Guide
[16] Application Note 28: Customer SIM Lock
Prior to using the MC55/56 engines or upgrading to a new firmware release, be sure to
carefully read the latest product information.
To visit the Siemens Website you can use the following link:
http://www.siemens.com/wm
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1.2 Terms and abbreviations
Abbreviation Description
ADC Analog-to-Digital Converter
AFC Automatic Frequency Control
AGC Automatic Gain Control
ANSI American National Standards Institute
ARFCN Absolute Radio Frequency Channel Number
ARP Antenna Reference Point
ASC0 / ASC1 Asynchronous Controller. Abbreviations used for first and second serial interface of
MC55/56
ASIC Application Specific Integrated Circuit
B Thermistor Constant
B2B Board-to-board connector
BER Bit Error Rate
BTS Base Transceiver Station
CB or CBM Cell Broadcast Message
CE Conformité Européene (European Conformity)
CHAP Challenge Handshake Authentication Protocol
CPU Central Processing Unit
CS Coding Scheme
CSD Circuit Switched Data
CTS Clear to Send
DAC Digital-to-Analog Converter
DAI Digital Audio Interface
dBm0 Digital level, 3.14dBm0 corresponds to full scale, see ITU G.711, A-law
DCE Data Communication Equipment (typically modems, e.g. Siemens GSM engine)
DCS 1800 Digital Cellular System, also referred to as PCN
DRX Discontinuous Reception
DSB Development Support Box
DSP Digital Signal Processor
DSR Data Set Ready
DTE Data Terminal Equipment (typically computer, terminal, printer or, for example, GSM
application)
DTR Data Terminal Ready
DTX Discontinuous Transmission
EFR Enhanced Full Rate
EGSM Enhanced GSM
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Abbreviation Description
EMC Electromagnetic Compatibility
ESD Electrostatic Discharge
ETS European Telecommunication Standard
FCC Federal Communications Commission (U.S.)
FDMA Frequency Division Multiple Access
FR Full Rate
GMSK Gaussian Minimum Shift Keying
GPRS General Packet Radio Service
GSM Global Standard for Mobile Communications
HiZ High Impedance
HR Half Rate
I/O Input/Output
IC Integrated Circuit
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IMEI International Mobile Equipment Identity
ISO International Standards Organization
ITU International Telecommunications Union
kbps kbits per second
LED Light Emitting Diode
Li-Ion Lithium-Ion
Mbps Mbits per second
MMI Man Machine Interface
MO Mobile Originated
MS Mobile Station (GSM engine), also referred to as TE
MSISDN Mobile Station International ISDN number
MT Mobile Terminated
NTC Negative Temperature Coefficient
OEM Original Equipment Manufacturer
PA Power Amplifier
PAP Password Authentication Protocol
PBCCH Packet Switched Broadcast Control Channel
PCB Printed Circuit Board
PCL Power Control Level
PCM Pulse Code Modulation
PCN Personal Communications Network, also referred to as DCS 1800
PCS Personal Communication System, also referred to as GSM 1900
PDU Protocol Data Unit
PLL Phase Locked Loop
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Abbreviation Description
PPP Point-to-point protocol
PSU Power Supply Unit
R&TTE Radio and Telecommunication Terminal Equipment
RAM Random Access Memory
RF Radio Frequency
RMS Root Mean Square (value)
ROM Read-only Memory
RTC Real Time Clock
Rx Receive Direction
SAR Specific Absorption Rate
SELV Safety Extra Low Voltage
SIM Subscriber Identification Module
SMS Short Message Service
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SRAM Static Random Access Memory
TA Terminal adapter (e.g. GSM engine)
TDMA Time Division Multiple Access
TE Terminal Equipment, also referred to as DTE
Tx Transmit Direction
UART Universal asynchronous receiver-transmitter
URC Unsolicited Result Code
USSD Unstructured Supplementary Service Data
VSWR Voltage Standing Wave Ratio
Phonebook abbreviations
FD SIM fixdialing phonebook
LD SIM last dialling phonebook (list of numbers most recently dialled)
MC Mobile Equipment list of unanswered MT calls (missed calls)
ME Mobile Equipment phonebook
ON Own numbers (MSISDNs) stored on SIM or ME
RC Mobile Equipment list of received calls
SM SIM phonebook
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1.3 Type approval
MC55/56 has been approved to comply with the directives and standards listed below and is
labeled with the CE conformity mark.
European directives
99/05/EC “Directive of the European Parliament and of the council of 9 March
1999 on radio equipment and telecommunications terminal equipment
and the mutual recognition of their conformity”, in short referred to as
89/336/EC Directive on electromagnetic compatibility
73/23/EC Directive on electrical equipment designed for use within certain
Standards of North American Type Approval
CFR Title 47 “Code of Federal Regulations, Part 22 and Part 24
UL 60 950 “Product Safety Certification” (Safety requirements)
NAPRD.03 “Overview of PCS Type certification review board
Mobile Equipment Type Certification and IMEI control”
PCS Type Certification Review board (PTCRB), Version 3.00
RSS133 (Issue2) Canadian Standard
Standards of European Type Approval
3GPP TS 51.010-1 “Digital cellular telecommunications system (Phase 2); Mobile Station
ETSI EN 301 511 “V7.0.1 (2000-12) Candidate Harmonized European Standard (Tele-
GCF-CC “Global Certification Forum - Certification Criteria” V3.15.0
ETSI EN 301 489-1 “V1.2.1 Candidate Harmonized European Standard (Tele-
ETSI EN 301 489-07 “V1.1.1 Electro Magnetic Compatibility and Radio spectrum Matters
EN 60 950 Safety of information technology equipment (2000)
R&TTE Directive 1999/5/EC
voltage limits (Low Voltage Directive)
(Telecommunications, PCS)”; US Equipment Authorization FCC
(MS) conformance specification”
communications
series) Global System for Mobile communications
(GSM); Harmonized standard for mobile stations in the GSM 900 and
DCS 1800 bands covering essential requirements under article 3.2 of
the R&TTE directive (1999/5/EC) (GSM 13.11 version 7.0.1 Release
1998)”
communications
series) Electro Magnetic Compatibility and Radio
spectrum Matters (ERM); Electro Magnetic Compatibility (EMC) standard
for radio equipment and services; Part 1: Common Technical
Requirements”
(ERM); Electro Magnetic Compatibility (EMC) standard for radio
equipment and services; Part 7: Specific conditions for mobile and
portable radio and ancillary equipment of digital cellular radio telecommunications systems (GSM and DCS)”
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Requirements of quality
IEC 60068 Environmental testing
DIN EN 60529 IP codes
Compliance with international rules and regulations
Manufacturers of mobile or fixed devices incorporating MC55/56 modules are advised to
have their completed product tested and approved for compliance with all applicable national
and international regulations. As a tri-band GSM/GPRS engine designed for use on any
GSM network in the world, MC55/56 is required to pass all approvals relevant to operation on
the European and North American markets. For the North American market this includes the
Rules and Regulations of the Federal Communications Commission (FCC) and PTCRB, for
the European market the R&TTE Directives and GCF Certification Criteria must be fully
satisfied.
The FCC Equipment Authorization granted to the MC55/56 Siemens reference application is
valid only for the equipment described in Chapter 7.
SAR requirements specific to handheld mobiles
Mobile phones, PDAs or other handheld transmitters and receivers incorporating a GSM
module must be in accordance with the guidelines for human exposure to radio frequency
energy. This requires the Specific Absorption Rate (SAR) of handheld MC55/56 based
applications to be evaluated and approved for compliance with national and/or international
regulations.
Since the SAR value varies significantly with the individual product design manufacturers are
advised to submit their product for approval if designed for handheld operation. For
European and US markets the relevant directives are mentioned below. It is the responsibility
of the manufacturer of the final product to verify whether or not further standards,
recommendations or directives are in force outside these areas.
Products intended for sale on US markets
ES 59005/ANSI C95.1 Considerations for evaluation of human exposure to Electromagnetic
Fields (EMFs) from Mobile Telecommunication Equipment (MTE) in
the frequency range 30MHz-6GHz
Products intended for sale on European markets
EN 50360 Product standard to demonstrate the compliance of mobile phones
with the basic restrictions related to human exposure to
electromagnetic fields (300 MHz - 3 GHz)
Note: Usage of MC55/56 in a handheld or portable application is not allowed without a
new FCC certification.
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1.4 Safety precautions
The following safety precautions must be observed during all phases of the operation, usage,
service or repair of any cellular terminal or mobile incorporating MC55/56. Manufacturers of
the cellular terminal are advised to convey the following safety information to users and
operating personnel and to incorporate these guidelines into all manuals supplied with the
product. Failure to comply with these precautions violates safety standards of design,
manufacture and intended use of the product. Siemens AG assumes no liability for customer
failure to comply with these precautions.
When in a hospital or other health care facility, observe the restrictions on the
use of mobiles. Switch the cellular terminal or mobile off, if instructed to do so
by the guidelines posted in sensitive areas. Medical equipment may be
sensitive to RF energy.
The operation of cardiac pacemakers, other implanted medical equipment
and hearing aids can be affected by interference from cellular terminals or
mobiles placed close to the device. If in doubt about potential danger, contact
the physician or the manufacturer of the device to verify that the equipment is
properly shielded. Pacemaker patients are advised to keep their hand-held
mobile away from the pacemaker, while it is on.
Switch off the cellular terminal or mobile before boarding an aircraft. Make
sure it cannot be switched on inadvertently. The operation of wireless
appliances in an aircraft is forbidden to prevent interference with
communications systems. Failure to observe these instructions may lead to
the suspension or denial of cellular services to the offender, legal action, or
both.
Do not operate the cellular terminal or mobile in the presence of flammable
gases or fumes. Switch off the cellular terminal when you are near petrol
stations, fuel depots, chemical plants or where blasting operations are in
progress. Operation of any electrical equipment in potentially explosive
atmospheres can constitute a safety hazard.
Your cellular terminal or mobile receives and transmits radio frequency
energy while switched on. Remember that interference can occur if it is used
close to TV sets, radios, computers or inadequately shielded equipment.
Follow any special regulations and always switch off the cellular terminal or
mobile wherever forbidden, or when you suspect that it may cause
interference or danger.
Road safety comes first! Do not use a hand-held cellular terminal or mobile
when driving a vehicle, unless it is securely mounted in a holder for handsfree
operation. Before making a call with a hand-held terminal or mobile, park the
vehicle.
Handsfree devices must be installed by qualified personnel. Faulty installation
or operation can constitute a safety hazard.
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IMPORTANT!
SOS
Cellular terminals or mobiles operate using radio signals and cellular
networks. Because of this connection cannot be guaranteed at all times under
all conditions. Therefore, you should never rely solely upon any wireless
device for essential communications, for example emergency calls.
Remember, in order to make or receive calls, the cellular terminal or mobile
must be switched on and in a service area with adequate cellular signal
strength.
Some networks do not allow for emergency calls if certain network services or
phone features are in use (e.g. lock functions, fixed dialling etc.). You may
need to deactivate those features before you can make an emergency call.
Some networks require that a valid SIM card be properly inserted in the
cellular terminal or mobile.
s
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2 Product concept
Designed for use on any GSM network in the world, Siemens MC55 is a tri-band GSM/GPRS
engine that works on the three frequencies GSM 900 MHz, GSM 1800 MHz and GSM
1900 MHz. MC56 is a tri-band GSM/GPRS engine that works on the three frequencies GSM
850MHz, GSM 1800 MHz and GSM 1900 MHz. MC55/56 features GPRS multislot class 10
and supports the GPRS coding schemes CS-1, CS-2, CS-3 and CS-4.
To save space on the application platform, MC55/56 comes as an extremely slim and
compact module. This makes it ideally suited for a broad range of mobile computing devices,
and particularly offers easy integration with smart phones, PDAs, and other handhelds.
The tiny MC55/56 module incorporates all you need to create high-performance GSM/GPRS
solutions: baseband processor, power supply ASIC, complete radio frequency circuit
including a power amplifier and antenna interface. The power amplifier is directly fed from the
supply voltage BATT+. A compact “stacked FLASH / SRAM” device stores the MC55/56
software in the flash memory section, and static RAM section provides the additional storage
capacity required by GPRS connectivity.
The physical interface to the cellular application is made through a board-to-board connector.
It consists of 50 pins, required for controlling the unit, transferring data and audio signals and
providing power supply lines.
MC55/56 comprises two serial interfaces (ASC0 and ASC1) giving you maximum flexibility
for easy integration with the Man-Machine Interface (MMI).
An extremely versatile audio concept offers various audio interfaces, each available on the
board-to-board connector: a digital audio interface (DAI) and two analog audio interfaces.
Using AT commands you can easily switch back and forth and select different audio modes.
The external dual-band or triple-band antenna can be connected optionally to a connector on
the top side or to a pad on the bottom side.
The power saving technique minimizes current consumption to as low as 3mA. In SLEEP
mode, MC55/56 is able to wake up on demand and to resume power saving automatically if
no activity is required.
For battery powered applications, MC55/56 features a charging control which can be used to
charge a Li-Ion battery. The charging circuit must be implemented outside the module on the
application platform.
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2.1 MC55/56 key features at a glance
Table 1: MC55/56 key features
Feature Implementation
Power supply Single supply voltage 3.3V – 4.8V
Power saving Minimizes power consumption in SLEEP mode to 3mA
Charging Supports charging control for Li-Ion battery
s
Frequency bands
GSM class Small MS
Transmit power
GPRS connectivity
Temperature range
Temperature control
and auto switch-off
DATA GPRS:
CSD:
WAP:
• MC55 Tri-band: EGSM 900, GSM 1800, GSM 1900
• MC56 Tri-band: GSM 850, GSM 1800, GSM 1900
• Compliant to GSM Phase 2/2+
• Class 4 (2W) at EGSM900 and GSM850
• Class 1 (1W) at GSM1800 and GSM 1900
• GPRS multi-slot class 10
• GPRS mobile station class B
• Normal operation: -20°C to +55°C
• Restricted operation: -25°C to -20°C and +55°C to +70°C
• Constant temperature control prevents damage to MC55/56 when the
specified temperature is exceeded. When an emergency call is in
progress the automatic temperature shutdown functionality is
deactivated.
• GPRS data downlink transfer: max. 85.6 kbps (see Table 2)
• GPRS data uplink transfer: max. 42.8 kbps (see Table 2)
• Coding scheme: CS-1, CS-2, CS-3 and CS-4
• MC55/56 supports the two protocols PAP (Password Authentication
Protocol) and CHAP (Challenge Handshake Authentication Protocol)
commonly used for PPP connections.
• Support of Packet Switched Broadcast Control Channel (PBCCH) allows
you to benefit from enhanced GPRS performance when offered by the
network operators.
• CSD transmission rates: 2.4, 4.8, 9.6, 14.4 kbps, non-transparent, V.110
• Unstructured Supplementary Services Data (USSD) support
• WAP compliant
SMS
MMS MMS compliant
FAX Group 3: Class 1, Class 2
SIM interface
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• MT, MO, CB, Text and PDU mode
• SMS storage: SIM card plus 25 SMS locations in the mobile equipment
• Transmission of SMS alternatively over CSD or GPRS. Preferred mode
can be user-defined.
• Supported SIM card: 3V
• External SIM card reader has to be connected via interface connector
(note that card reader is not part of MC55/56)
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Feature Implementation
External antenna Connected via 50 Ohm antenna connector or antenna pad
Audio interfaces Two analog audio interfaces, one digital audio interface (DAI)
Audio features Speech codec modes:
• Half Rate (ETS 06.20)
• Full Rate (ETS 06.10)
• Enhanced Full Rate (ETS 06.50 / 06.60 / 06.80)
• Adaptive Multi Rate (AMR)
Handsfree operation
• Echo cancellation
• Noise reduction
Two serial interfaces:
ASC0, ASC1
Phonebook
management
SIM Application Toolkit Supports SAT class 3, GSM 11.14 Release 98, support of letter class “c”
Ringing tones Offers a choice of 7 different ringing tones / melodies, easily selectable with
Real time clock Implemented
Timer function Programmable via AT command
Support of TTY/CTM To benefit from TTY communication via GSM, CTM equipment can be
Physical characteristics Size: 35+0.15 x 32.5+0.15 x 3.1+0.3 mm (including
• 2.65V level, bi-directional bus for AT commands and data
• ASC0 – full-featured 8-wire serial interface. Supports RTS0/CTS0
hardware handshake and software XON/XOFF flow control. Multiplex
ability according to GSM 07.10 Multiplexer Protocol.
• ASC1 - 4-wire serial interface. Supports RTS1/CTS1 hardware
handshake and software XON/XOFF flow control.
• Baud rate: 300bps ... 230kbps on ASC0 and ASC1
• Autobauding (on ASC0 only) detects 1200, 2400, 4800, 9600, 19200,
38400, 57600, 115200, 230400 bps
Supported phonebook types: SM, FD, LD, MC, RC, ON, ME
AT command
connected to one of the three audio interfaces.
application connector)
35+0.15 x 32.5+0.15 x 2.95+0.2 mm (excluding
application connector)
Weight: 5.5g
Firmware upgrade Firmware upgradable over serial interface and SIM interface
Evaluation kit The DSB45 Support Box is an evaluation kit designed to test and type
approve Siemens cellular engines and provide a sample configuration for
application engineering. See Chapter 9 for ordering information.
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Table 2: Coding schemes and maximum net data rates over air interface
Coding scheme 1 Timeslot 2 Timeslots 4 Timeslots
CS-1: 9.05 kbps 18.1 kbps 36.2 kbps
CS-2: 13.4 kbps 26.8 kbps 53.6 kbps
CS-3: 15.6 kbps 31.2 kbps 62.4 kbps
CS-4: 21.4 kbps 42.8 kbps 85.6 kbps
Please note that the values stated above are maximum ratings which, in practice, are influenced by a
great variety of factors, primarily, for example, traffic variations and network coverage.
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2.2 Circuit concept
Figure 1 shows a block diagram of the MC55/56 module and illustrates the major functional
components:
GSM / GPRS baseband block:
• Baseband controller operating at 26MHz
• Power supply ASIC
• Stacked Flash / SRAM
• Application interface (board-to-board connector)
GSM RF block:
• Skyworks RF transceiver
• Skyworks RF power amplifier / FEM
• RF front end (antenna connector)
MC5x
RF Power
Amplifi er
RF Section
Measuring
Network
Interface
RF - Baseband
Send
Receive
Control
CCRST
CCCLK
CCIO
CCIN
CCVCC
(GND)
Power
Supply
ASIC
Baseband
Controller
4
2
Data
Adr
Control
Data
Adr
Control
5
9
8
4
6
SIM Interface
/EMERGOFF
POWER
CHARGE
5
5
BATT_TEMP
DAI
2x Audio
ASC0
ASC1
SYNC
VDD
VDDLP
/IGT
BATT+
GND
SRAM
Flash
CCIN
CCVCC
4
(50 pins)
Application Interface
Ext.
Charging
Circuit
+
SIM
Charger
input
NTC
Figure 1: MC55/56 block diagram
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3 Application Interface
MC55/56 is equipped with a 50-pin 0.5mm pitch board-to-board connector that connects to
the cellular application platform. The host interface incorporates several sub-interfaces
described in the following chapters:
• Power supply and charging control (see Chapters 3.2 and 3.3)
• Dual serial interface (see Chapter 3.9)
• Two analog audio interfaces and a digital audio interface (see Chapter 3.10)
• SIM interface (see Chapter 3.11)
Electrical and mechanical characteristics of the board-to-board connector are specified in
Chapter 6.3. Ordering information for mating connectors and cables are included.
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3.1 Operating modes
The table below briefly summarizes the various operating modes referred to in the following
chapters.
Table 3: Overview of operating modes
Mode Function
Normal operation
GSM / GPRS SLEEP Various powersave modes set with AT+CFUN
command.
Software is active to minimum extent. If the module was
registered to the GSM network in IDLE mode, it is
registered and paging with the BTS in SLEEP mode,
too. Power saving can be chosen at different levels:
The NON-CYCLIC SLEEP mode (AT+CFUN=0)
disables the AT interface. The CYCLIC SLEEP modes
AT+CFUN=5, 6, 7, 8 and 9 alternatively activate and
deactivate the AT interfaces to allow permanent access
to all AT commands.
GSM IDLE Software is active. Once registered to the GSM
network, paging with BTS is carried out. The module is
ready to send and receive.
GSM TALK Connection between two subscribers is in progress.
Power consumption depends on network coverage
individual settings, such as DTX off/on, FR/EFR/HR,
hopping sequences, antenna.
GPRS IDLE Module is ready for GPRS data transfer, but no data is
currently sent or received. Power consumption depends
on network settings and GPRS configuration (e.g.
multislot settings).
GPRS DATA GPRS data transfer in progress. Power consumption
depends on network settings (e.g. power control level),
uplink / downlink data rates and GPRS configuration
(e.g. used multislot settings).
POWER DOWN Normal shutdown after sending the AT^SMSO command.
The Power Supply ASIC (PSU-ASIC) disconnects the supply voltage from the
baseband part of the circuit. Only a voltage regulator in the PSU-ASIC is active
for powering the RTC. Software is not active. The serial interfaces are not
accessible.
Operating voltage (connected to BATT+) remains applied.
Alarm mode Restricted operation launched by RTC alert function while the module is in
POWER DOWN mode. Module will not be registered to GSM network. Limited
number of AT commands is accessible.
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Mode Function
Charge-only mode Limited operation for battery powered applications. Enables charging while
module is detached from GSM network. Limited number of AT commands is
accessible. There are several ways to launch Charge-only mode:
• From POWER DOWN mode: Connect charger to the charger input pin of the
external charging circuit and the module’s POWER pin when MC55/56 was
powered down by AT^SMSO.
• From Normal mode: Connect charger to the charger input pin of the external
charging circuit and the module’s POWER pin, then enter AT^SMSO.
Charge mode
during normal
operation
See Table 11 and Table 12 for the various options of waking up MC55/56 and proceeding from one
mode to another.
Normal operation (SLEEP, IDLE, TALK, GPRS IDLE, GPRS DATA) and
charging running in parallel. Charge mode changes to Charge-only mode when
the module is powered down before charging has been completed.
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3.2 Power supply
s
The power supply of MC55/56 has to be a single voltage source of V
+= 3.3V...4.8V. It
BATT
must be able to provide sufficient current in a transmit burst which typically rises to 2A.
Beyond that, the power supply must be able to account for increased current consumption if
the module is exposed to inappropriate conditions, for example antenna mismatch. For
further details see Chapters 3.2.2 and 5.4.1.
All the key functions for supplying power to the device are handled by an ASIC power supply.
The ASIC provides the following features:
• Stabilizes the supply voltages for the GSM baseband using low drop linear voltage
regulators.
• Controls the module's power up and power down procedures.
A watchdog logic implemented in the baseband processor periodically sends signals to
the ASIC, allowing it to maintain the supply voltage for all digital MC55/56 components.
Whenever the watchdog pulses fail to arrive constantly, the module is turned off.
• Delivers, across the VDD pin, a regulated voltage of 2.9V. The output voltage VDD may
be used to supply, for example, an external LED or a level shifter. However, the external
circuitry must not cause any spikes or glitches on voltage VDD. This voltage is not
available in POWER DOWN mode. Therefore, the VDD pin can be used to indicate
whether or not MC55/56 is in POWER DOWN mode.
• Provides power to the SIM interface.
The RF power amplifier is driven directly from BATT+.
3.2.1 Power supply pins on the board-to-board connector
Five BATT+ pins of the board-to-board connector are dedicated to connect the supply
voltage, five GND pins are recommended for grounding. The values stated below must be
measured directly at the reference points on the MC55/56 board (TP BATT+ and TP GND
illustrated in Figure 40).
The POWER and CHARGE pins serve as control signals for charging a Li-Ion battery.
VDDLP can be used to back up the RTC.
Table 4: Power supply pins of board-to-board connector
Signal name I/O Description Parameter
BATT+ I/O Positive operating voltage
Reference points are the
test points
GND - Ground 0 V
POWER I This line signals to the
processor that the charger
is connected.
CHARGE O Control signal for external
charging transistor
VDDLP I/O Can be used to back up
the RTC when V
applied.
See Chapter 3.8
BATT+
is not
3.3 V...4.8 V, I
The minimum operating voltage must not fall
below 3.3 V, not even in case of voltage drop.
U
UIN = 2.0 V...5.5 V
Ri = 1kΩ
I
in,max
OUT,max
= 30µA
< V
≤ 2 A during transmit burst
typ
BATT+
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3.2.2 Minimizing power losses
When designing the power supply for your application please pay specific attention to power
losses. Ensure that the input voltage V
not even in a transmit burst where current consumption can rise to typical peaks of 1.6A. It
should be noted that MC55/56 switches off when exceeding these limits. Any voltage drops
that may occur in a transmit burst should not exceed 400mV. For further details see Chapter
5.4.
The best approach to reducing voltage drops is to use a board-to-board connection as
recommended, and a low impedance power source. The resistance of the power supply lines
on the host board and of a battery pack should also be considered.
Note: If the application design requires an adapter cable between both board-to-board
connectors, use a cable as short as possible in order to minimize power losses.
Example: If the length of the cable reaches the maximum length of 200mm, this connection
may cause, for example, a resistance of 50m in the BATT+ line and 50m in
the GND line. As a result, a 1.6A transmit burst would add up to a total voltage
drop of 160mV. Plus, if a battery pack is involved, further losses may occur due
to the resistance across the battery lines and the internal resistance of the battery
including its protective circuit.
never drops below 3.3V on the MC55/56 board,
BATT+
Transmit
burst 1.6A
BATT+
min. 3.3V
Figure 2: Power supply limits during transmit burst
Transmit
burst 1.6A
Ripple
Drop
The input voltage V
must be measured directly at the test points on the MC55/56 board
BATT+
(TP BATT+ and TP GND illustrated in Figure 40).
3.2.3 Monitoring power supply
To help you monitor the supply voltage you can use the AT^SBV command which returns the
voltage measured at TP BATT+ and GND.
The voltage is continuously measured at intervals depending on the operating mode on the
RF interface. The duration of measuring ranges from 0.5s in TALK/DATA mode up to 50s
when MC55/56 is in IDLE mode or Limited Service (deregistered). The displayed voltage (in
mV) is averaged over the last measuring period before the AT^SBV command was executed.
For details please refer to [1].
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3.3 Power up / down scenarios
In general, be sure not to turn on MC55/56 while it is out of the operating range of voltage
and temperature stated in Chapters 5.2 and 5.3. MC55/56 would immediately switch off after
having started and detected these inappropriate conditions.
3.3.1 Turn on MC55/56
MC55/56 can be activated in a variety of ways, which are described in the following chapters:
• via ignition line /IGT: starts normal operating state (see Chapters 3.3.1.1 and 3.3.1.2)
• via POWER line: starts charging algorithm (see Chapters 3.5.3 and 3.3.1.3)
• via RTC interrupt: starts Alarm mode (see Chapter 3.3.1.4)
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3.3.1.1 Turn on MC55/56 using the ignition line /IGT (Power on)
To switch on MC55/56 the /IGT (Ignition) signal needs to be driven to ground level for at least
100ms and not earlier than 10ms after the last falling edge of VDD. This can be
accomplished using an open drain/collector driver in order to avoid current flowing into this
pin.
BATT+
min. 10ms
min.
/IGT
HiZ
ca. 60ms
100ms
HiZ
VDD
/TXD0
/TXD1
/DSR0
/EMERGOFF
Serial interfaces
ASC0 and ASC1
For details please see Chapter 3.3.1.2
Software
controlled
Undefined
ca. 300ms ca. 900ms
Inactive
Active
Figure 3: Power-on by ignition signal
If configured to a fix baud rate, MC55/56 will send the result code ^SYSSTART to indicate
that it is ready to operate. This result code does not appear when autobauding is active. See
Chapter AT+IPR in [1].
In a battery operated MC55/56 application, the duration of the /IGT signal must be 1s
minimum when the charger is connected and you may want to go from Charge only mode to
Normal mode.
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3.3.1.2 Timing of the ignition process
When designing your application platform take into account that powering up MC55/56
requires the following steps.
• The ignition line cannot be operated until V
• The ignition line shall not be operated earlier than 10ms after the last falling edge of VDD.
• 10ms after V
has reached 3.0V the ignition line can be switched low. The duration of
BATT+
the falling edge must not exceed 1ms.
• Another 100ms are required to power up the module.
• Ensure that V
does not fall below 3.0V while the ignition line is driven. Otherwise the
BATT+
module cannot be activated.
• If the VDDLP line is fed from an external power supply as explained in Chapter 3.8, the
/IGT line is HiZ before the rising edge of BATT+.
3.0V
passes the level of 3.0V.
BATT+
BATT+
/IGT
BATT+
/IGT
0V
HiZ
10ms
min. 100ms
max. 1ms
Figure 4: Timing of power-on process if VDDLP is not used
3.0V
0V
HiZ
HiZ
HiZ
10ms
min. 100ms
max. 1ms
Figure 5: Timing of power-on process if VDDLP is fed from external source
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3.3.1.3 Turn on MC55/56 using the POWER signal
As detailed in Chapter 3.5.3, the charging adapter can be connected regardless of the
module’s operating mode.
If the charger is connected to the charger input of the external charging circuit and the
module’s POWER pin while MC55/56 is off, processor controlled fast charging starts (see
Chapter 3.5.2). MC55/56 enters a restricted mode, referred to as Charge-only mode where
only the charging algorithm will be launched.
During the Charge-only mode MC55/56 is neither logged on to the GSM network nor are the
serial interfaces fully accessible. To switch to normal operation and log on to the GSM
network, the /IGT line needs to be activated.
3.3.1.4 Turn on MC55/56 using the RTC (Alarm mode)
Another power-on approach is to use the RTC, which is constantly supplied with power from
a separate voltage regulator in the power supply ASIC. The RTC provides an alert function,
which allows the MC55/56 to wake up whilst the internal voltage regulators are off. To
prevent the engine from unintentionally logging into the GSM network, this procedure only
enables restricted operation, referred to as Alarm mode. It must not be confused with a
wake-up or alarm call that can be activated by using the same AT command, but without
switching off power.
Use the AT+CALA command to set the alarm time. The RTC retains the alarm time if
MC55/56 was powered down by AT^SMSO. Once the alarm is timed out and executed,
MC55/56 enters the Alarm mode. This is indicated by an Unsolicited Result Code (URC)
which reads:
^SYSSTART ALARM MODE
Note that this URC is the only indication of the Alarm mode and will not appear when
autobauding was activated (due to the missing synchronization between DTE and DCE upon
start-up). Therefore, it is recommended to select a fixed baudrate before using the Alarm
mode. In Alarm mode only a limited number of AT commands is available. For further
instructions refer to the AT Command Set.
Table 5: AT commands available in Alarm mode
AT command Use
AT+CALA Set alarm time
AT+CCLK Set date and time of RTC
AT^SBC In Alarm mode, you can only query the present current consumption and check
whether or not a charger is connected. The battery capacity is returned as 0,
regardless of the actual voltage (since the values measured directly on the cell are
not delivered to the module).
AT^SCTM Query temperature range, enable/disable URCs to report critical temperature
ranges
AT^SMSO Power down GSM engine
For the GSM engine to change from the Alarm mode to full operation (normal operating
mode) it is necessary to drive the ignition line to ground. This must be implemented in your
host application as described in Chapter 3.3.1.1.
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If the charger is connected to the POWER line when MC55/56 is in ALARM mode charging
will start, while MC55/56 stays in ALARM mode. See also Chapter 3.7 which summarizes the
various options of changing the mode of operation.
If your host application uses the SYNC pin to control a status LED as described in Chapter
3.12.2.2, please note that the LED is off while the GSM engine is in Alarm mode.
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3.3.2 Turn off MC55/56
To switch the module off the following procedures may be used:
• Normal shutdown procedure: Software controlled by sending the AT^SMSO command
over the serial application interface. See Chapter 3.3.2.1.
• Emergency shutdown: Hardware driven by switching the /EMERGOFF line of the board-
to-board-connector to ground = immediate shutdown of supply voltages, only applicable
if the software controlled procedure fails! See Chapter 3.3.2.2.
• Automatic shutdown: See Chapter 3.3.3
a) Takes effect if undervoltage is detected.
b) Takes effect if MC55/56 board temperature exceeds critical limit.
3.3.2.1 Turn off MC55/56 using AT command
The best and safest approach to powering down MC55/56 is to issue the AT^SMSO
command. This procedure lets MC55/56 log off from the network and allows the software to
enter into a secure state and safe data before disconnecting the power supply. The mode is
referred to as POWER DOWN mode. In this mode, only the RTC stays active.
Before switching off the device sends the following response:
^SMSO: MS OFF
OK
^SHUTDOWN
After sending AT^SMSO do not enter any other AT commands. There are two ways to verify
when the module turns off:
• Wait for the URC “^SHUTDOWN”. It indicates that data have been stored non-volatile
and the module turns off in less than 1 second.
• Also, you can monitor the VDD pin. The low state of VDD definitely indicates that the
module is switched off.
Be sure not to disconnect the operating voltage V
been issued and the VDD signal has gone low. Otherwise you run the risk of losing data.
While MC55/56 is in POWER DOWN mode the application interface is switched off and must
not be fed from any other source. Therefore, your application must be designed to avoid any
current flow into any digital pins of the application interface.
Note: In POWER DOWN mode, the /EMERGOFF pin, the output pins of the ASC0 interface
/RXD0, /CTS0, /DCD0, /DSR0, /RING0 and the output pins of the ASC1 interface
/RXD1 and /CTS1 are switched to high impedance state.
If this causes the associated input pins of your application to float, you are advised to
integrate an additional resistor (100 k – 1 M) at each line. In the case of the
/EMERGOFF pin use a pull-down resistor tied to GND. In the case of the serial
interface pins you can either connect pull-up resistors to the VDD line, or pull-down
resistors to GND.
before the URC “^SHUTDOWN” has
BATT+
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3.3.2.2 Emergency shutdown using /EMERGOFF pin
Caution: Use the /EMERGOFF pin only when, due to serious problems, the software is
not responding for more than 5 seconds. Pulling the /EMERGOFF pin causes
the loss of all information stored in the volatile memory since power is cut off
immediately. Therefore, this procedure is intended only for use in case of
emergency, e.g. if MC55/56 fails to shut down properly.
The /EMERGOFF signal is available on the board-to-board connector. To control the
/EMERGOFF line it is recommended to use an open drain / collector driver. To turn the GSM
engine off, the /EMERGOFF line has to be driven to ground for ≥ 3.2s.
BATT+
/IGT
VDD
Internal reset
/EMERGOFF
Controlled by MC55/56
Figure 6: Deactivating GSM engine by /EMERGOFF signal
max. 3.2s
Controlled by external application
How does it work:
• Voltage V
• The module is active while the
is permanently
BATT+
applied to the module.
internal reset signal is kept at
high level.
During operation of MC55/56
the baseband controlle
generates watchdog pulses at
regular intervals.
Once the EMERGOFF pin is
grounded these watchdog
pulses are cut off from the
power supply ASIC. The powe
supply ASIC shuts down the
internal supply voltages o
MC55/56 after max. 3.2s and
the module turns off.
Consequently, the output
voltage at VDD is switched off.
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3.3.3 Automatic shutdown
Automatic shutdown takes effect if
• the MC55/56 board is exceeding the critical limits of overtemperature or
undertemperature
• the battery is exceeding the critical limits of overtemperature or undertemperature
• undervoltage is detected
The automatic shutdown procedure is equivalent to the power-down initiated with the
AT^SMSO command, i.e. MC55/56 logs off from the network and the software enters a
secure state avoiding loss of data. NOTE: This does not apply if overvoltage conditions or
unrecoverable hardware or software errors occur (see below for details).
Alert messages transmitted before the device switches off are implemented as Unsolicited
Result Codes (URCs). The presentation of these URCs can be enabled or disabled with the
two AT commands AT^SBC and AT^SCTM. The URC presentation mode varies with the
condition, please see Chapters 3.3.3.1 to 3.3.3.4 for details. For further instructions on AT
commands refer to [1].
3.3.3.1 Temperature dependent shutdown
The board temperature is constantly monitored by an internal NTC resistor located on the
PCB. The NTC that detects the battery temperature must be part of the battery pack circuit
as described in Chapter 3.5. The values detected by either NTC resistor are measured
directly on the board or the battery and therefore, are not fully identical with the ambient
temperature.
Each time the board or battery temperature goes out of range or back to normal, MC55/56
instantly displays an alert (if enabled).
• URCs indicating the level "1" or "-1" allow the user to take appropriate precautions, such
as protecting the module from exposure to extreme conditions. The presentation of the
URCs depends on the settings selected with the AT^SCTM write command:
AT^SCTM=1: Presentation of URCs is always enabled.
AT^SCTM=0 (default): Presentation of URCs is enabled for 15 seconds time after
start-up of MC55/56. After 15 seconds operation, the presentation will be disabled,
i.e. no alert messages can be generated.
• URCs indicating the level "2" or "-2" are instantly followed by an orderly shutdown. The
presentation of these URCs is always enabled, i.e. they will be output even though the
factory setting AT^SCTM=0 was never changed.
The maximum temperature ratings are stated in Table 25. Refer to Table 6 for the associated
URCs. All statements are based on test conditions according to IEC 60068-2-2 (still air).
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Table 6: Temperature dependent behaviour
Sending temperature alert (15 s after start-up, otherwise only if URC presentation enabled)
^SCTM_A: 1 Caution: T
^SCTM_B: 1 Caution: T
^SCTM_A: -1 Caution: T
^SCTM_B: -1 Caution: T
^SCTM_A: 0 Battery back to uncritical temperature range.
^SCTM_B: 0 Board back to uncritical temperature range.
Automatic shutdown (URC appears no matter whether or not presentation was enabled)
^SCTM_A: 2 Alert: T
^SCTM_B: 2 Alert: T
^SCTM_A: -2 Alert: T
^SCTM_B: -2 Alert: T
of battery close to over temperature limit.
amb
of board close to over temperature limit.
amb
of battery close to under temperature limit.
amb
of board close to under temperature limit.
amb
of battery equal or beyond over temperature limit. MC55/56 switches off.
amb
of board equal or beyond over temperature limit. MC55/56 switches off.
amb
of battery equal or below under temperature limit. MC55/56 switches off.
amb
of board equal or below under temperature limit. MC55/56 switches off.
amb
3.3.3.2 Temperature control during emergency call
If the temperature limit is exceeded while an emergency call is in progress the engine
continues to measure the temperature, but deactivates the shutdown functionality. If the
temperature is still out of range when the call ends, the module switches off immediately
(without another alert message).
3.3.3.3 Undervoltage shutdown if battery NTC is present
In applications where the module’s charging technique is used and an NTC is connected to
the BATT_TEMP terminal, the software constantly monitors the applied voltage. If the
measured battery voltage is no more sufficient to set up a call the following URC will be
presented:
^SBC: Undervoltage.
The message will be reported, for example, when you attempt to make a call while the
voltage is close to the critical limit and further power loss is caused during the transmit burst.
To remind you that the battery needs to be charged soon, the URC appears several times
before the module switches off.
To enable or disable the URC use the AT^SBC command. The URC will be enabled when
you enter the write command and specify the power consumption of your GSM application.
Step by step instructions are provided in [1].
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3.3.3.4 Undervoltage shutdown if no battery NTC is present
The undervoltage protection is also effective in applications, where no NTC connects to the
BATT_TEMP terminal. Thus, you can take advantage of this feature even though the
application handles the charging process or MC55/56 is fed by a fixed supply voltage. All you
need to do is executing the write command AT^SBC=<current> which automatically enables
the presentation of URCs. You do not need to specify <current>.
Whenever the supply voltage falls below the specified value (see Table 27) the URC
^SBC: Undervoltage
appears several times before the module switches off.
3.3.3.5 Overvoltage shutdown
For overvoltage conditions, no software controlled shutdown is implemented. If the supply
voltage exceeds the maximum value specified in Table 27, loss of data and even
unrecoverable hardware damage can occur.
Keep in mind that several MC55/56 components are directly linked to BATT+ and, therefore,
the supply voltage remains applied at major parts of MC55/56. Especially the power amplifier
is very sensitive to high voltage and might even be destroyed.
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3.4 Automatic GPRS Multislot Class change
s
Temperature control is also effective for operation in GPRS Multislot Class 10. If the board
temperature increases to the limit specified for restricted operation
transmitted over GPRS, the module automatically reverts from GPRS Multislot Class 10 (2
Tx) to Class 8 (1Tx). This reduces the power consumption and, consequently, causes the
board’s temperature to decrease. Once the temperature drops to a value of 5 degrees below
the limit of restricted operation, MC55/56 returns to the higher Multislot Class. If the
temperature stays at the critical level or even continues to rise, MC55/56 will not switch back
to the higher class.
After a transition from Multislot Class 10 to Multislot 8 a possible switchback to Multislot
Class 10 is blocked for one minute.
Please note that there is not one single cause of switching over to a lower GPRS Multislot
Class. Rather it is the result of an interaction of several factors, such as the board
temperature that depends largely on the ambient temperature, the operating mode and the
transmit power. Furthermore, take into account that there is a delay until the network
proceeds to a lower or, accordingly, higher Multislot Class. The delay time is network
dependent. In extreme cases, if it takes too much time for the network and the temperature
cannot drop due to this delay, the module may even switch off as described in chapter
3.3.3.1.
1)
See Table 25 for temperature limits known as restricted operation.
1)
while data are
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3.5 Charging control
MC55/56 integrates a charging management for Li-Ion batteries. You can skip this chapter if
charging is not your concern, or if you are not using the implemented charging algorithm.
MC55/56 has no on-board charging circuit. To benefit from the implemented charging
management you are required to install a charging circuit within your application. In this case,
MC55/56 needs to be powered from a Li-Ion battery pack, e.g. as specified in Table 8.
The module only delivers, via its POWER line and CHARGE line, the control signals needed
to start and stop the charging process. The charging circuit should include a transistor and
should be designed as illustrated in Figure 7. A list of parts recommended for the external
circuit is given in Table 7.
Input from
charger
(5.5V - 8V)
under load
470R
1SS355
to POWER
to BATT+
PCB spark
gap
100nF 10k
4V3
SI3441DV
3k3
Battery
pack
CRS04
NTC
+
-
1
/5 ESDA6V1-5W6
BATT_TEMP
1
/5 ESDA6V1-5W6
CHARGE
Figure 7: Schematic of approved charging transistor, trickle charging and ESD protection
Table 7: Bill of material for external charging circuit
Part Description First supplier Second supplier
SI3441DV
p-chan 2.5V (G-S) MOSFET
(TSOP-6)
VISHAY: SI3441DV-T1 NEC: UPA1911TE-T1
1SS355 100mA Si-diode (UMD2) ROHM: 1SS355TE-18 Toshiba: 1SS352TPH3
CRS04 1A Schottky diode Toshiba: CRS04 -
4V3
ESDA6V1-5W6
250mW; 200mA;
4.3V Z-Diode (SOD323)
ESD protection TRANSIL™
array
Philips: PDZ4.3B
STM: ESDA6V1-5W6 -
ROHM: UDZS4.3B
UDZ4.3B
470R, 3k3, 10k Resistor, e.g. 0805 or 0603 - -
100nF Ceramic capacitor 50V - -
PCB spark gap 0.2mm spark gap on PCB - -
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3.5.1 Battery pack characteristics
The charging algorithm has been optimised for a Li-Ion battery pack that meets the
characteristics listed below and in Table 8. It is recommended that the battery pack you want
to integrate into your MC55/56 application is compliant with these specifications. This
ensures reliable operation, proper charging and, particularly, allows you to monitor the
battery capacity using the AT^SBC command (see [1] for details). Failure to comply with
these specifications might cause AT^SBC to deliver incorrect battery capacity values.
• Li-Ion battery pack specified for a maximum charging voltage of 4.2 V and a capacity of
800 mAh. Battery packs with a capacity down to 600 mAh or more than 800 mAh are
allowed, too.
• Since charging and discharging largely depend on the battery temperature, the battery
pack should include an NTC resistor. If the NTC is not inside the battery it must be in
thermal contact with the battery. The NTC resistor must be connected between
BATT_TEMP and GND. Required NTC characteristics are: 10 kΩ +
3435K +
note that the NTC is indispensable for proper charging, i.e. the charging process will not
start if no NTC is present.
• Ensure that the pack incorporates a protection circuit capable of detecting overvoltage
(protection against overcharging), undervoltage (protection against deep discharging)
and overcurrent. The circuit must be insensitive to pulsed current.
• On the MC55/56 module, a built-in measuring circuit constantly monitors the supply
voltage. In the event of undervoltage, it causes MC55/56 to power down. Undervoltage
thresholds are specific to the battery pack and must be evaluated for the intended model.
When you evaluate undervoltage thresholds, consider both the current consumption of
MC55/56 and
• The internal resistance of the battery and the protection should be as low as possible. It
is recommended not to exceed 150m, even in extreme conditions at low temperature.
The battery cell must be insensitive to rupture, fire and gassing under extreme conditions
of temperature and charging (voltage, current).
• The battery pack must be protected from reverse pole connection. For example, the
casing should be designed to prevent the user from mounting the battery in reverse
orientation.
• The battery pack must be approved to satisfy the requirements of CE conformity.
Figure 8 shows the circuit diagram of a typical
battery pack design that includes the protection
elements described above.
3% (alternatively acceptable: 10 kΩ +2% @ 25°C, B
of the application circuit.
to BATT+
25/50
to BATT_TEMP to GND
5% @ 25°C, B
= 3370K +3%). Please
25/85
=
ϑ
Figure 8: Battery pack circuit diagram
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Protection Circuit
-
+
Battery cell
Polyfuse
NTC
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Table 8: Specifications of recommended battery pack
Battery type Li-Ion, 3.6V
Nominal voltage 3.6V
Capacity 800mAh
NTC 10k ± 5% @ 25°C, B (25/85)=3435K ± 3%
Overcharge detection voltage 4.325 ± 0.025V
Overcharge release voltage 4.075 ± 0.025V
Overdischarge detection voltage 2.5 ± 0.05V
Overdischarge release voltage 2.9 ± 0.5V
Overcurrent detection 3 ± 0.5A
Nominal working current <5µA
Current of low voltage detection 0.5µA
Overcurrent detection delay time 8~16ms
Short detection delay time 50µs
Overdischarge detection delay time 31~125ms
Overcharge detection delay time 1s
Internal resistance <130m
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3.5.2 Implemented charging technique
If the external charging circuit follows the recommendation of Figure 7, the charging process
consists of trickle charging and processor controlled fast charging. For this solution, the fast
charging current provided by the charger or any other external source must be limited to
500mA.
Trickle charging
• Trickle charging starts when the charger is connected to the charger input of the external
charging circuit and the module’s POWER pin. The charging current depends on the
voltage difference between the charger input of the external charging circuit and BATT+
of the module.
• Trickle charging stops when the battery voltage reaches 3.6V.
Fast charging
• After trickle charging has raised the battery voltage to 3.2V within 60 minutes +
connecting the charger, the power ASIC turns on and wakes up the baseband processor.
Now, processor controlled fast charging begins.
If the battery voltage was already above 3.2V, processor controlled fast charging starts
just after the charger was connected to the charger input of the external charging circuit
and the module’s POWER pin. If MC55/56 was in POWER DOWN mode, it turns on and
enters the Charge-only mode along with fast charging (see also Chapter 3.3.1.3).
• Fast charging delivers a constant current until the battery voltage reaches 4.2V and then
proceeds with varying charge pulses. As shown in Figure 5, the pulse duty cycle is
reduced to adjust the charging procedure and prevent the voltage from overshooting
beyond 4.2V. Once the pulse width reaches the minimum of 100ms and the duty cycle
does not change for 2 minutes, fast charging is completed.
• Fast charging can only be accomplished in a temperature range from 0°C to +45°C.
Voltage
10% from
4.3
4.2
3.8
3.4
3.0
Constant current
100ms 2 ... 0.1s
t
= 100 ms
OFF
100ms 0.1 ... 2s
t
= 100 ms
ON
Time
Figure 9: Charging process
Note: Do not connect the charger to the BATT+ lines. Only the charger input of the
external charging circuit is intended as input for charging current! The POWER pin
of MC55/56 is the input only for indicating a connected charger!
The battery manufacturer must guarantee that the battery complies with the
described charging technique.
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What to do if software controlled charging does not start up?
If trickle charging fails to raise the battery voltage to 3.2V within 60 minutes +
10%, processor
controlled charging does not begin. To start fast charging you can do one of the following:
• Once the voltage has risen above its minimum of 3V, you can try to start software
controlled charging by pulling the /IGT line to ground.
• If the voltage is still below 3V, driving the /IGT line to ground switches the timer off.
Without the timer running, MC55/56 will not proceed to software controlled charging. To
restart the timer you are required to shortly disconnect and reconnect the charger.
3.5.3 Operating modes during charging
Of course, the battery can be charged regardless of the engine's operating mode. When the
GSM engine is in Normal mode (SLEEP, IDLE, TALK, GPRS IDLE or GPRS DATA mode), it
remains operational while charging is in progress (provided that sufficient voltage is applied).
The charging process during the Normal mode is referred to as Charge mode.
If the charger is connected to the charger input of the external charging circuit and the
module’s POWER pin while MC55/56 is in POWER DOWN mode, MC55/56 goes into
Charge-only mode.
Table 9: Comparison Charge-only and Charge mode
How to activate mode Features
Connect charger to charger input of
external charging circuit and module’s
POWER pin while MC55/56 is
• operating, e.g. in IDLE or TALK mode
• in SLEEP mode
Charge mode
Connect charger to charger input of
external charging circuit and module’s
POWER pin while MC55/56 is
• in POWER DOWN mode
• in Normal mode: Connect charger to
the POWER pin, then enter
AT^SMSO.
IMPORTANT: While trickle charging is in
progress, be sure that the application is
switched off. If the application is fed from
Charge-only mode
the trickle charge current the module
might be prevented from proceeding to
software controlled charging since the
current would not be sufficient.
• Battery can be charged while GSM engine
remains operational and registered to the
GSM network.
• In IDLE and TALK mode, the serial interfaces
are accessible. AT command set can be used
to full extent.
• In the NON-CYCLIC SLEEP mode, the serial
interfaces are not accessible at all. During the
CYCLIC SLEEP mode it can be used as
described in Chapter 3.6.3.
• Battery can be charged while GSM engine is
deregistered from GSM network.
• Charging runs smoothly due to constant
current consumption.
• The AT interface is accessible and allows to
use the commands listed below.
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Features of Charge-only mode
Once the GSM engine enters the Charge-only mode, the AT command interface presents an
Unsolicited Result Code (URC) which reads:
^SYSSTART CHARGE-ONLY MODE
Note that this URC will not appear when autobauding was activated (due to the missing
synchronization between DTE and DCE upon start-up). Therefore, it is recommended to
select a fixed baudrate before using the Charge-only mode.
While the Charge-only mode is in progress, you can only use the AT commands listed in
Table 10. For further instructions refer to the AT Command Set supplied with your GSM
engine.
Table 10: AT commands available in Charge-only mode
AT command Use
AT+CALA Set alarm time
AT+CCLK Set date and time of RTC
AT^SBC Monitor charging process
Note: While charging is in progress, no battery capacity value is available. To query
the battery capacity disconnect the charger.
If the charger connects externally to the host device no charging parameters are
transferred to the module. In this case, the command cannot be used.
AT^SCTM Query temperature range, enable/disable URCs to report critical temperature
ranges
AT^SMSO Power down GSM engine
To proceed from Charge-only mode to normal operation, it is necessary to drive the ignition
line to ground. This must be implemented in your host application as described in Chapter
3.3.1.1. See also Chapter 3.7 which summarizes the various options of changing the mode of
operation.
If your host application uses the SYNC pin to control a status LED as described in Chapter
3.12.2.2, please note that the LED is off while the GSM engine is in Charge-only mode.
3.5.4 Charger requirements
If you are using the implemented charging technique and the charging circuit recommended
in Figure 7, the charger must be designed to meet the following requirements:
a) Simple transformer power plug
- Output voltage: 5.5V...8V (under load)
- The charge current must be limited to 500mA
- Voltage spikes that may occur while you connect or disconnect the charger must be
limited.
- There must not be any capacitor on the secondary side of the power plug (avoidance of
current spikes at the beginning of charging)
b) Supplementary requirements for a) to ensure a regulated power supply
- When current is switched off a voltage peak of 10V is allowed for a maximum 1ms
- When current is switched on a spike of 1.6A for 1ms is allowed
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3.6 Power saving
SLEEP mode reduces the functionality of the MC55/56 module to a minimum and, thus,
minimizes the current consumption to the lowest level. Settings can be made using the
AT+CFUN command. For details see below and [1]. SLEEP mode falls into two categories:
• NON-CYCLIC SLEEP mode AT+CFUN=0
• CYCLIC SLEEP modes, selectable with AT+CFUN=5, 6, 7, 8 or 9.
IMPORTANT: Please keep in mind that power saving works properly only when PIN
authentication has been done. If you attempt to activate power saving while the SIM card is
not inserted or the PIN not correctly entered (Limited Service), the selected <fun> level will
be set, though power saving does not take effect. For the same reason, power saving cannot
be used if MC55/56 operates in Alarm mode.
To check whether power saving is on, you can query the status of AT+CFUN if you have
chosen CYCLIC SLEEP mode. If available, you can take advantage of the status LED
controlled by the SYNC pin (see Chapter 3.12.2.2). The LED is off in all SLEEP modes when
no activity occurs, but resumes flashing to indicate temporary wake-up states during CYLCIC
SLEEP modes. The LED patterns are shown in Table 18.
The wake-up procedures are quite different depending on the selected SLEEP mode. Table
11 compares the wake-up events that can occur in NON-CYCLIC and CYCLIC SLEEP
modes.
3.6.1 No power saving (AT+CFUN=1)
The functionality level <fun>=1 is where power saving is switched off. This is the default after
startup.
3.6.2 NON-CYCLIC SLEEP mode (AT+CFUN=0)
If level 0 has been selected (AT+CFUN=0), the serial interface is blocked. The module
shortly deactivates power saving to listen to a paging message sent from the base station
and then immediately resumes power saving. Level 0 is called NON-CYCLIC SLEEP mode,
since the serial interface is not alternatingly made accessible as in CYCLIC SLEEP mode.
The first wake-up event fully activates the module, enables the serial interface and
terminates the power saving mode. In short, it takes MC55/56 back to the highest level of
functionality <fun>=1. /RTS0 or /RTS1 are not used for flow control, but to wake up the
module.
3.6.3 CYCLIC SLEEP mode (AT+CFUN=5, 6, 7, 8)
The major benefit over the NON-CYCLIC SLEEP mode is that the serial interface is not
permanently blocked and that packet switched calls may go on without terminating the
selected CYCLIC SLEEP mode. This allows MC55/56 to become active, for example to
perform a GPRS data transfer, and to resume power saving after the GPRS data transfer is
completed.
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The CYCLIC SLEEP modes give you greater flexibility regarding the wake-up procedures:
For example, in all CYCLIC SLEEP modes, you can enter AT+CFUN=1 to permanently wake
up the module. In modes CFUN=7 and 8, MC55/56 automatically resumes power saving,
after you have sent or received a short message or made a call. CFUN=5 and 6 do not offer
this feature, and therefore, are only supported for compatibility with earlier releases. Please
refer to Table 11 for a summary of all modes.
The CYCLIC SLEEP mode is a dynamic process which alternatingly enables and disables
the serial interface. By setting/resetting the /CTS signal, the module indicates to the
application whether or not the UART is active. The timing of /CTS is described below.
Both the application and the module must be configured to use hardware flow control
(RTS/CTS handshake). The default setting of MC55/56 is AT\Q0 (no flow control) which must
be altered to AT\Q3. See [1] for details.
Note: If both serial interfaces ASC0 and ASC1 are connected, both are synchronized. This
means that SLEEP mode takes effect on both, no matter on which interface the AT
command was issued. Although not explicitly stated, all explanations given in this
chapter refer equally to ASC0 and ASC1, and accordingly to /CTS0 and /CTS1.
s
3.6.4 CYCLIC SLEEP mode AT+CFUN=9
Mode AT+CFUN=9 is similar to AT+CFUN=7 or 8, but provides two additional features:
• /RTS0 and /RTS1 are not intended for flow control (as in modes AT+CFUN=5, 6, 7 or 8),
but can be used to temporarily wake up the module. This way, the module can quickly
wake up and resume power saving, regardless of the /CTS timing controlled by the
paging cycle.
• The time the module stays active after RTS was asserted or after the last character was
sent or received, can be configured individually using the command AT^SCFG. Default
setting is 2 seconds like in AT+CFUN=7. The entire range is from 0.5 seconds to 1 hour,
selectable in tenths of seconds. For details see [1].
3.6.5 Timing of the /CTS signal in CYCLIC SLEEP modes
The /CTS signal is enabled in synchrony with the module’s paging cycle. It goes active low
each time when the module starts listening to a paging message block from the base station.
The timing of the paging cycle varies with the base station. The duration of a paging interval
can be calculated from the following formula:
4.615 ms (TDMA frame duration) * 51 (number of frames) * DRX value.
DRX (Discontinuous Reception) is a value from 2 to 9, resulting in paging intervals from 0.47
to 2.12 seconds. The DRX value of the base station is assigned by the network operator.
Each listening period causes the /CTS signal to go active low: If DRX is 2, the /CTS signal is
activated every 0.47 seconds, if DRX is 3, the /CTS signal is activated every 0.71 seconds
and if DRX is 9, the /CTS signal is activated every 2.1 seconds.
The /CTS signal is active low for 4.6 ms. This is followed by another 4.6 ms UART activity. If
the start bit of a received character is detected within these 9.2 ms, /CTS will be activated
and the proper reception of the character will be guaranteed.
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/CTS will also be activated if any character is to be sent.
After the last character was sent or received the interface will remain active for
• another 2 seconds, if AT+CFUN=5 or 7,
• another 10 minutes, if AT+CFUN=6 or 8,
• or for an individual time defined with AT^SCFG, if AT+CFUN=9. Assertion of RTS has the
same effect.
In the pauses between listening to paging messages, while /CTS is high, the module
resumes power saving and the AT interface is not accessible. See Figure 10 and Figure 11.
Paging message Paging message Paging message
/CTS
4.6
ms
AT interface disabled
4.6 ms
2.12 s
2.12 s
4.6
ms
4.6 ms
AT interface enabled
4.6
ms
4.6 ms
Paging message
2.12 s
4.6
ms
4.6 ms
Figure 10: Timing of /CTS signal (example for a 2.12 s paging cycle)
Figure 11 illustrates the CFUN=5 and CFUN=7 modes, which reset the /CTS signal 2
seconds after the last character was sent or received.
Paging message Paging message
2.12 s
2.12 s
Paging message
Paging message
2.12 s
Beginning of power saving
/CTS
1 characterstLast character
AT interface disabled
2 s
AT interface enabled
4.6 ms
4.6
ms
4.6 ms
4.6
ms
4.6 m
Figure 11: Beginning of power saving if CFUN=5 or 7
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3.6.6 Wake up MC55/56 from SLEEP mode
A wake-up event is any event that causes the module to draw current. Depending on the
selected mode the wake-up event either switches SLEEP mode off and takes MC55/56 back
to AT+CFUN=1, or activates MC55/56 temporarily without leaving the current SLEEP mode.
Definitions of the state transitions described in Table 11:
Quit = MC55/56 exits SLEEP mode and returns to AT+CFUN=1.
Temporary = MC55/56 becomes active temporarily for the duration of the event and the
mode-specific follow-up time after the last character was sent or received
on the serial interface.
No effect: = Event is not relevant in the selected SLEEP mode. MC55/56 does not
wake up.
Table 11: Wake-up events in NON-CYCLIC and CYCLIC SLEEP modes
Event Selected mode
AT+CFUN=0
Ignition line No effect No effect No effect
/RTS0 or /RTS1 1)
(falling edge)
Unsolicited Result Code
(URC)
Incoming voice or data call Quit Quit Temporary
Any AT command
(incl. outgoing voice or data
call, outgoing SMS)
Incoming SMS depending on
mode selected by AT+CNMI:
AT+CNMI=0,0 (= default, no
indication of received SMS)
AT+CNMI=1,1 (= displays
URC upon receipt of SMS)
Quit No effect (RTS is only
Quit Quit Temporary
Not possible
(UART disabled)
No effect
Quit
Selected mode
AT+CFUN=5 or 6
used for flow control)
Temporary Temporary
No effect
Quit
Selected mode
AT+CFUN=7, 8, 9
Mode 7 and 8: No
effect (RTS is only
used for flow control)
Mode 9: Temporary
No effect
Temporary
GPRS data transfer Not possible
(UART disabled)
RTC alarm2) Quit Quit Temporary
AT+CFUN=1 Not possible
(UART disabled)
Temporary Temporary
Quit Quit
1)
During the CYCLIC SLEEP modes 5, 6, 7, and 8, /RTS0 and /RTS1 are conventionally
used for flow control: The assertion of /RTS0 or /RTS1 signals that the application is
ready to receive data - without waking up the module. If the module is in CFUN=0
mode the assertion of /RTS0 and /RTS1 serves as a wake-up event, giving the
application the possibility to intentionally terminate power saving. If the module is in
CFUN=9 mode, the assertion of /RTS0 or /RTS1 can be used to temporarily wake up
MC55/56 for the time specified with the AT^SCFG command (default = 2s).
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2)
Recommendation: In NON-CYCLIC SLEEP mode, you can set an RTC alarm to wake
up MC55/56 and return to full functionality. This is a useful approach because, in this
mode, the AT interface is not accessible.
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3.7 Summary of state transitions (except SLEEP mode)
Table 12: State transitions of MC55/56 (except SLEEP mode)
The table shows how to proceed from one mode to another (grey column = present mode, white columns = intended modes)
Further mode ÎÎÎ
Present mode
POWER DOWN Normal mode
**)
Charge-only mode*) Charging in normal
mode
*)**)
s
Alarm mode
POWER DOWN
mode without charger
POWER DOWN
mode with charger
(high level at POWER
--- /IGT >100 ms at low
level
--- /IGT >1 s at low level,
if battery is fully
charged
pins of MC55/56)
Normal mode
**)
AT^SMSO
--- No automatic transition,
or
exceptionally /EMERGOFF
pin > 3.2s at low level
Charge-only mode *) Disconnect charger
(MC55/56 POWER pin at
low level)
or
AT^SMSO or
No automatic
transition, but via
“Charge in Normal
mode”
exceptionally /EMERGOFF
pin >
3.2s at low level
Charging in normal
mode*)
**)
AT^SMSO Î “Chargeonly mode”, again
AT^SMSO;
or
exceptionally /EMERG-
Disconnect charger
from input of ext.
charging circuit and
module’s POWER pin
OFF pin >3.2s at low level
Alarm mode AT^SMSO or
exceptionally /EMERGOFF
pin >
*)
See Chapter 3.5.3 for details on the charging mode
3.2s at low level
/IGT >100ms at low
level
Connect charger to
input of ext. charging
circuit and POWER pin
No direct transition, but
via “Charge-only mode”
or “Normal mode”
Wake-up from POWER
DOWN mode (if
activated with AT+CALA)
(high level at POWER)
100ms < /IGT < 500ms
at low level
/IGT >1 s at low level Wake-up from POWER
DOWN mode (if
activated with AT+CALA)
but via “POWER
DOWN”
Connect charger to
POWER pin at MC55/56
(high level at POWER)
AT+CALA followed by
AT^SMSO. MC55/56
enters Alarm mode when
specified time is reached.
--- /IGT >1s at low level AT+CALA followed by
AT^SMSO. MC55/56
enters Alarm mode when
specified time is reached
and V
BATT+
AT^SMSO --- No direct transition
AT^SMSO if charger is
/IGT >100ms at low level ---
connected
**)
Normal mode covers TALK, DATA, GPRS, IDLE and SLEEP modes
>3.2V
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3.8 RTC backup
The internal Real Time Clock of MC55/56 is supplied from a separate voltage regulator in the
power supply ASIC which is also active when MC55/56 is in POWER DOWN status. An
alarm function is provided that allows to wake up MC55/56 without logging on to the GSM
network.
In addition, you can use the VDDLP pin on the board-to-board connector to backup the RTC
from an external capacitor or a battery (rechargeable or non-chargeable). The capacitor is
charged by the BATT+ line of MC55/56. If the voltage supply at BATT+ is disconnected the
RTC can be powered by the capacitor. The size of the capacitor determines the duration of
buffering when no voltage is applied to MC55/56, i.e. the greater capacitor the longer
MC55/56 will save the date and time.
The following figures show various sample configurations. The voltage applied at VDDLP can
be in the range from 2 to 5.5V. Please refer to Table 26 for the parameters required.
Baseband
processor
RTC
PSU
1k
B2B
BATT+
VDDLP
+
Figure 12: RTC supply from capacitor
BATT+
Baseband
processor
PSU
RTC
B2B
1k
VDDLP
+
Figure 13: RTC supply from rechargeable battery
BATT+
Baseband
processor
RTC
PSU
B2B
1k
VDDLP
+
+
Figure 14: RTC supply from non-chargeable battery
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3.9 Serial interfaces
MC55/56 offers two unbalanced, asynchronous serial interfaces conforming to ITU-T V.24
protocol DCE signalling. The electrical characteristics do not comply with ITU-T V.28. The
significant levels are 0V (for low data bit or ON condition) and 2.65V (for high data bit or OFF
condition). For electrical characteristics please refer to Table 26.
The GSM engine is designed for use as a DCE. Based on the conventions for DCE-DTE
connections it communicates with the customer application (DTE) using the following signals:
ASC0
• Port /TXD @ application sends data to the module’s /TXD0 signal line
• Port /RXD @ application receives data from the module’s /RXD0 signal line
ASC1
• Port /TXD @ application sends data to module’s /TXD1 signal line
• Port /RXD @ application receives data from the module’s /RXD1 signal line
GSM module
(DCE)
ASC0 interface
/TXD0
/RXD0
/RTS0
/CTS0
/DTR0
/DSR0
/DCD0
/RING0
/TXD1
/RXD1
/RTS1
/TXD
/RXD
/RTS
/CTS
/DTR
/DSR
/DCD
/RING
/TXD
/RXD
/RTS
Application
(DTE)
serial interface
st
1
/CTS1
ASC1 interface
Figure 15: Serial interfaces
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serial interface
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2
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3.9.1 Features supported on first and second serial interface
ASC0
• 8-wire serial interface
• Includes the data lines /TXD0 and /RXD0, the status lines /RTS0 and /CTS0 and, in
addition, the modem control lines /DTR0, /DSR0, /DCD0 and /RING0.
• It is primarily designed for voice calls, CSD calls, fax calls and GPRS services and for
controlling the GSM engine with AT commands. Full Multiplex capability allows the
interface to be partitioned into three virtual channels, yet with CSD and fax services only
available on the first logical channel. Please note that when the ASC0 interface runs in
Multiplex mode, ASC1 cannot be used. For more detailed characteristics see [11].
• The /DTR0 signal will only be polled once per second from the internal firmware of
MC55/56.
• The /RING0 signal serves to indicate incoming calls and other types of URCs (Unsolicited
Result Code). It can also be used to send pulses to the host application, for example to
wake up the application from power saving state. For further details see Chapter
3.12.2.3.
• Autobauding is only selectable on ASC0 and supports the following bit rates: 1200, 2400,
4800, 9600, 19200, 38400, 57600, 115200, 230400 bps.
• Autobauding is not compatible with multiplex mode, see [11].
ASC1
• 4-wire serial interface
• Includes only the data lines /TXD1 and /RXD1 plus /RTS1 and /CTS1 for hardware
handshake. This interface is intended for voice calls, GPRS services and for controlling
the GSM engine with AT commands. It is not suited for CSD calls, fax calls and Multiplex
mode.
• On ASC1 no RING line is available. The indication of URCs on the second interface
depends on the settings made with the AT^SCFG command. For details refer to [1].
ASC0 and ASC1
• Both interfaces are configured for 8 data bits, no parity and 1 stop bit, and can be
operated at bit rates from 300bps to 230400 bps.
• XON/XOFF software flow control can be used on both interfaces (except if power saving
is active).
Table 13: DCE-DTE wiring of 1st serial interface
DCE DTE V.24
circuit
103 /TXD0 Input /TXD Output
104 /RXD0 Output /RXD Input
105 /RTS0 Input /RTS Output
106 /CTS0 Output /CTS Input
108/2 /DTR0 Input /DTR Output
107 /DSR0 Output /DSR Input
109 /DCD0 Output /DCD Input
125 /RING0 Output /RING Input
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Table 14: DCE-DTE wiring of 2nd serial interface
DCE DTE V.24
circuit
103 /TXD1 Input /TXD Output
104 /RXD1 Output /RXD Input
105 /RTS1 Input /RTS Output
106 /CTS1 Output /CTS Input
Pin function Signal direction Pin function Signal direction
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3.10 Audio interfaces
MC55/56 comprises three audio interfaces available on the board-to-board connector:
• Two analog audio interfaces, each with a balanced analog microphone input and a
balanced analog earpiece output. The second analog interface provides a supply circuit
to feed an active microphone.
• Serial digital audio interface (DAI) using PCM (Pulse Code Modulation) to encode analog
voice signals into digital bit streams.
This means you can connect up to three audio devices in any combination, although analog
and digital audio cannot be operated at the same time. Using the AT^SAIC command you
can easily switch back and forth.
MICP1
MICN1
MICP2
MICN2
EPP1
M
U
X
ADC
EPN1
EPP2
DAC
DSP
Air
Interface
EPN2
SCLK
RXDDAI
RFSDAI
TXDDAI
TFSDAI
MC55/56 offers six audio modes which can be selected with the AT^SNFS command, no
matter which of the three interfaces is currently active. The electrical characteristics of the
voiceband part vary with the audio mode. For example, sending and receiving amplification,
sidetone paths, noise suppression etc. depend on the selected mode and can be altered with
AT commands (except for mode 1).
On each audio interface you can use all audio AT commands specified in [1] to alter
parameters. The only exception are the DAC and ADC gain amplifier attenuation
<outBbcGain> and <inBbcGain> which cannot be modified when the digital audio interface is
used, since in this case the DAC and ADC are switched off.
Please refer to Chapter 3.10 for specifications of the audio interface and an overview of the
audio parameters. Detailed instructions on using AT commands are presented in [1]. Table
29 on page 88 summarizes the characteristics of the various audio modes and shows what
parameters are supported in each mode.
Digital
Audio
Interface
DAI
Figure 16: Audio block diagram
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When shipped from factory, all audio parameters of MC55/56 are set to interface 1 and audio
mode 1. This is the default configuration optimised for the Votronic HH-SI-30.3/V1.1/0
handset and used for type approving the Siemens reference configuration. Audio mode 1 has
fix parameters which cannot be modified. To adjust the settings of the Votronic handset
simply change to another audio mode.
In transmit direction, all audio modes contain internal scaling factors (digital amplification)
that are not accessible by the user. To avoid saturation with a full scale digital input signal on
the DAI, and to obtain a one-to-one digital access to the speech coder in audio mode 5
and 6, it is recommended to set the parameter <inCalibrate> of the selected audio mode as
follows:
Audio mode 1 and 4: 23196
Audio mode 2: 17396
Audio mode 3: 21901
Audio mode 5 and 6: 21402
3.10.1 Microphone circuit
Interface 1
This interface has no microphone supply circuit and therefore, has an impedance of 50k
Ω.
When connecting a microphone or another signal source to interface 1 you are required to
add two 100 nF capacitors, one to each line.
Interface 2
This interface comes with a microphone supply circuit and can be used to feed an active
microphone. It has an impedance of 2k
Ω. If you do not use it or if you want to connect
another type of signal source, for example, an op amp or a dynamic microphone, it needs to
be decoupled with capacitors. The power supply can be switched off and on by using the
command AT^SNFM. For details see [1].
Figure 17 shows the microphone inputs at both analog interfaces of MC55/56.
2.65 V
Power down
MICP1
MICN1
Ri=50k
to ADC
MICP2
MICN2
k
1
33 µF
1 k 1
k
Ri=2
1
k
k
Figure 17: Schematic of microphone inputs
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3.10.2 Speech processing
The speech samples from the ADC or DAI are handled by the DSP of the baseband
controller to calculate e.g. amplifications, sidetone, echo cancellation or noise suppression
depending on the configuration of the active audio mode. These processed samples are
passed to the speech encoder. Received samples from the speech decoder are passed to
the DAC or DAI after post processing (frequency response correction, adding sidetone etc.).
Full rate, half rate, enhanced full rate, adaptive multi rate (AMR), speech and channel
encoding including voice activity detection (VAD) and discontinuous transmission (DTX) and
digital GMSK modulation are also performed on the GSM baseband processor.
Customer specific audio parameters can be evaluated and supplied by Siemens on request.
These parameters can be downloaded to MC55/56 using an AT command. For further
information refer to [9] or contact your Siemens distributor.
3.10.3 DAI timing
To support the DAI function, MC55/56 integrates a simple five-line serial interface with one
input data clock line (SCLK) and input / output data and frame lines (TXDDAI, TFSDAI,
RXDDAI, RFSDAI).
The serial interface is always active if the external input data clock SLCK is present, i.e. the
serial interface is not clocked by the DSP of the MC55/56 baseband processor. SLCK must
be supplied from the application and can be in a frequency range between 0.2 and 10 MHz.
Serial transfer of 16-bit words is done in both directions.
Data transfer to the application is initiated by the module via a short pulse of TFSDAI. The
duration of the TFSDAI pulse is one SCLK period, starting at the rising edge of SLCK. During
the following 16 SLCK cycles, the 16-bit sample will be transferred on the TXDDAI line. The
next outgoing sample will be transferred after the next TFSDAI pulse which occurs every 125
µs.
The TFSDAI pulse is the master clock of the sample transfer. From the rising edge of the
TFSDAI pulse, the application has 100 µs to transfer the 16-bit input sample on the RXDDAI
line. The rising edge of the RFSDAI pulse (supplied by the application) may coincide with the
falling edge of TFSDAI or occur slightly later - it is only significant that, in any case, the
transfer of the LSB input sample will be completed within the specified duration of 100 µs.
Audio samples are transferred from the module to the application in an average of 125µs.
This is determined by the 8kHz sampling rate, which is derived from and synchronized to the
GSM network. As SLCK is independent of the GSM network, the distance between two
succeeding sample transfers may vary about +
The application is required to adapt its sampling rate to the TFSDAI rate. Failure to
synchronize the timing between the module and the application may cause audible pops and
clicks in a conversation. The timing characteristics of both data transfer directions are shown
in Figure 18 and Figure 19.
1 SLCK period.
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Note: Before starting the data transfer the clock SCLK should be available for at least
three cycles.
After the transfer of the LSB0 the clock SCLK should be still available for at least
three cycles.
SLCK
(input)
Internal
signal
RFSDAI
(input)
RXDDAI
(input)
Flag
SLCK
(input)
Internal
signal
T = 100ns to 5,000 ns
Figure 18: DAI timing on transmit path
T = 100ns to 5,000 ns
TFSDAI
(output)
TXDDAI
(output)
Flag
Figure 19: DAI timing on receive path
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3.11 SIM interface
The baseband processor has an integrated SIM interface compatible with the ISO 7816 IC
Card standard. This is wired to the host interface (board-to-board connector) in order to be
connected to an external SIM card holder. Six pins on the board-to-board connector are
reserved for the SIM interface.
The CCIN pin serves to detect whether a tray (with SIM card) is present in the card holder.
Using the CCIN pin is mandatory for compliance with the GSM 11.11 recommendation if the
mechanical design of the host application allows the user to remove the SIM card during
operation. See Chapter 3.11.1 for details.
Table 15: Signals of the SIM interface (board-to-board connector)
Signal Description
CCGND Separate ground connection for SIM card to improve EMC.
CCCLK Chipcard clock, various clock rates can be set in the baseband processor.
CCVCC SIM supply voltage from PSU-ASIC
CCIO Serial data line, input and output.
CCRST Chipcard reset, provided by baseband processor.
CCIN Input on the baseband processor for detecting a SIM card tray in the holder.
The CCIN pin is mandatory for applications that allow the user to remove the SIM card
during operation.
The CCIN pin is solely intended for use with a SIM card. It must not be used for any other
purposes. Failure to comply with this requirement may invalidate the type approval of
MC55/56.
It is recommended that the total cable length between the board-to-board connector pins on
MC55/56 and the pins of the SIM card holder does not exceed 200 mm in order to meet the
specifications of 3GPP TS 51.010-1 and to satisfy the requirements of EMC compliance.
To avoid possible cross-talk from the CCCLK signal to the CCIO signal be careful that both
lines are not placed closely next to each other. A useful approach is using the CCGND line to
shield the CCIO line from the CCCLK line.
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3.11.1 Requirements for using the CCIN pin
According to ISO/IEC 7816-3 the SIM interface must be immediately shut down once the SIM
card is removed during operation. Therefore, the signal at the CCIN pin must go low before
the SIM card contacts are mechanically detached from the SIM interface contacts. This shutdown procedure is particularly required to protect the SIM card as well as the SIM interface
of MC55/56 from damage.
An appropriate SIM card detect switch is required on the card holder. For example, this is
true for the model supplied by Molex, which has been tested to operate with MC55/56 and is
part of the Siemens reference equipment submitted for type approval. Molex ordering
number is 91228-0001, see also Chapter 9.
The module’s startup procedure involves a SIM card initialisation performed within 1 second
after getting started. An important issue is whether the initialisation procedure ends up with a
high or low level of the CCIN signal:
a) If, during startup of MC55/56, the CCIN signal on the SIM interface is high, then the
status of the SIM card holder can be recognized each time the card is inserted or
ejected.
A low level of CCIN indicates that no SIM card tray is inserted into the holder. In this
case, the module keeps searching, at regular intervals, for the SIM card. Once the SIM
card tray with a SIM card is inserted, CCIN is taken high again.
b) If, during startup of MC55/56, the CCIN signal is low, the module will also attempt to
initialise the SIM card. In this case, the initialisation will only be successful when the
card is present.
If the SIM card initialisation has been done, but the card is no more operational or
removed, then the module will never search again for a SIM card and only emergency
calls can be made.
Removing and inserting the SIM card during operation requires the software to be
reinitialised. Therefore, after reinserting the SIM card it is necessary to restart MC55/56.
It is strongly recommended to connect the contacts of the SIM card detect switch to the CCIN
input and to the CCVCC output of the module as illustrated in the sample diagram in Figure
20.
Note: No guarantee can be given, nor any liability accepted, if loss of data is encountered
after removing the SIM card during operation.
Also, no guarantee can be given for properly initialising any SIM card that the user
inserts after having removed a SIM card during operation. In this case, the application
must restart MC55/56.
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3.11.2 Design considerations for SIM card holder
The schematic below is a sample configuration that illustrates the Molex SIM card holder
located on the DSB45 Support Box (evaluation kit used for type approval of the Siemens
MC55/56 reference setup, see [5]). X503 is the designation used for the SIM card holder in
[5].
Molex card holder
Figure 20: SIM card holder of DSB45 Support Box
Table 16: Pin assignment of Molex SIM card holder on DSB45 Support Box
Pin no. Signal name I/O Function
1 CCVCC I Supply voltage for SIM card, generated by the GSM engine
2 CCRST I Chip card reset, prompted by the GSM engine
3 CCCLK I Chip card clock
4 CCGND - Individual ground line for the SIM card to improve EMC
5 CCVPP - Not connected
6 CCIO I/O Serial data line, bi-directional
7 CCDET1 - Connect to CCVCC
8 CCDET2 Connects to the CCIN input of the GSM engine. Serves to
recognize whether a SIM card is in the holder.
GSM module
Pins 1 through 8 (except for 5) are the minimum
requirement according to the GSM Recommendations,
where pins 7 and 8 are needed for SIM card tray
detection through the CCIN pin.
4
5
6
1
2
3
Figure 21: Pin numbers of Molex SIM card holder on DSB45
Support Box
8
7
Place the capacitors C1205 and C1206 (or instead one capacitor of 200nF) as close as
possible to the pins 1 (CCVCC) and 4 (GND) of the card holder. Connect the capacitors to
the pins via low resistance tracks.
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3.12 Control signals
3.12.1 Inputs
Table 17: Input control signals of the MC55/56 module
Signal Pin Pin status Function Remarks
s
Ignition
Emergency
shutdown
/IGT
/EMERGOFF
(HiZ = high impedance)
Falling edge Power up MC55/56
Left open or HiZ No operation
Low Power down
MC55/56
Left open or HiZ No operation
Active low ≥ 100ms (Open
drain/collector driver to GND
required in cellular device
application).
Note: If a charger and a
battery is connected to the
customer application the /IGT
signal must be 1s minimum.
Active low ≥ 3.2s (Open
drain/collector driver required
in cellular device application).
At the /EMERGOFF signal the
watchdog signal of the GSM
engine can be traced (see
description in Table 26).
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3.12.2 Outputs
3.12.2.1 Synchronization signal
The synchronization signal serves to indicate growing power consumption during the transmit
burst. The signal is generated by the SYNC pin. Please note that this pin can adopt two
different operating modes which you can select by using the AT^SSYNC command (mode 0
and 1). For details refer to the following chapter and to [1].
To generate the synchronization signal the pin needs to be configured to mode 0 (= default).
This setting is recommended if you want your application to use the synchronization signal
for better power supply control. Your platform design must be such that the incoming signal
accommodates sufficient power supply to the MC55/56 module if required. This can be
achieved by lowering the current drawn from other components installed in your application.
The timing of the synchronization signal is shown below. High level of the SYNC pin
indicates increased power consumption during transmission.
1 Tx 577 µs every 4.616 ms
2 Tx 1154 µs every 4.616 ms
Transmit burst
SYNC signal
*)
The duration of the SYNC signal is always equal, no matter whether the traffic or the
*)
300 µs
Figure 22: SYNC signal during transmit burst
access burst are active.
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3.12.2.2 Using the SYNC pin to control a status LED
As an alternative to generating the synchronization signal, the SYNC pin can be used to
control a status LED on your application platform.
Especially in the development and test phase of an application, system integrators are
advised to use the LED mode of the SYNC pin in order to evaluate their product design and
identify the source of errors.
To avail of this feature you need to set the SYNC pin to mode 1 by using the AT^SSYNC
command. For details see [1].
When controlled from the SYNC pin the LED can display the functions listed in Table 18.
Except for the LED state "off", all LED patterns apply no matter whether MC55/56 works at
full functionality level AT+CFUN=1 or has entered a "temporary wake-up state" during one of
the CYCLIC SLEEP modes. See Chapter 3.6 for details on the various SLEEP modes.
Table 18: Coding of the status LED
LED mode Operating status of MC55/56
Permanently off MC55/56 is in one of the following modes: POWER DOWN mode,
ALARM mode, CHARGE-ONLY mode, SLEEP mode with no wake-up
event in progress.
600 ms on / 600 ms off Limited Network Service: No SIM card inserted or no PIN entered, or
network search in progress, or ongoing user authentication, or network
login in progress.
75 ms on / 3 s off IDLE mode: The mobile is logged to the network (monitoring control
channels and user interactions). No call in progress.
75 ms on / 75 ms off /
75 ms on / 3 s off
0.5 s on / off depending on
transmission activity
Permanently on Depending on type of call:
LED Off = SYNC pin low. LED On = SYNC pin high (if LED is connected as illustrated in Figure 23)
One or more GPRS contexts activated.
Packet switched data transfer in progress. LED goes on within
1 second after data packets were exchanged. Flash duration is
approximately 0.5 s.
Voice call: Connected to remote party.
CSD call: Connected to remote party or exchange of parameters while
setting up or disconnecting a call.
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To operate the LED a buffer, e.g. a transistor or gate,
must be included in your application. A sample
configuration can be gathered from Figure 23. Power
consumption in the LED mode is the same as for the
synchronization signal mode. For details see Table 26,
SYNC pin.
Figure 23: LED Circuit (Example)
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3.12.2.3 Behavior of the /RING0 line (ASC0 interface only)
The /RING0 line is available on the first serial interface (ASC0). The signal serves to indicate
incoming calls and other types of URCs (Unsolicited Result Code).
Although not mandatory for use in a host application, it is strongly suggested that you
connect the /RING0 line to an interrupt line of your application. In this case, the application
can be designed to receive an interrupt when a falling edge on /RING0 occurs. This solution
is most effective, particularly, for waking up an application from power saving. Note that if the
/RING0 line is not wired, the application would be required to permanently poll the data and
status lines of the serial interface at the expense of a higher current consumption. Therefore,
utilizing the /RING0 line provides an option to significantly reduce the overall current
consumption of your application.
The behavior of the /RING0 line varies with the type of event:
• When a voice call comes in the /RING0 line goes low for 1s and high for another 4s.
Every 5 seconds the ring string is generated and sent over the /RXD0 line.
If there is a call in progress and call waiting is activated for a connected handset or
handsfree device, the /RING0 line switches to ground in order to generate acoustic
signals that indicate the waiting call.
4s
4s
/RING0
1s
Ring
string
Figure 24: Incoming voice call
1s
Ring
string
1s
Ring
string
• Likewise, when a Fax or data call is received, /RING0 goes low. However, in contrast to
voice calls, the line remains low. Every 5 seconds the ring string is generated and sent
over the /RXD0 line.
5s
Ring
string
/RING0
Ring
string
5s
Ring
string
Figure 25: Incoming data call
• All types of Unsolicited Result Codes (URCs) also cause the
/RING0 line to go low, however for 1 second only.
RING0
For example, MC55/56 may be configured to output a URC
upon the receipt of an SMS. As a result, if this URC type
was activated with AT+CNMI=1,1, each incoming SMS
causes the /RING0 line to go low. See [1] for detailed
1s
URC
information on URCs.
Figure 26: URC transmission
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Table 19: MC55/56 ring signal
Function Pin Status Description
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Ring indication /RING0
0 Indicates an incoming call or URC. If in NON-CYCLIC
SLEEP mode CFUN=0 or CYCLIC SLEEP mode
CFUN=5 or 6, the module is caused to wake up to full
functionality. If CFUN=7 or 8, power saving is resumed
after URC transmission or end of call.
1 No operation
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4 Antenna interface
The RF interface has an impedance of 50. MC55/56 is capable of sustaining a total
mismatch at the antenna connector or pad without any damage, even when transmitting at
maximum RF power.
The external antenna must be matched properly to achieve best performance regarding
radiated power, DC-power consumption and harmonic suppression. Matching networks are
not included on the MC55/56 PCB and should be placed in the host application.
Regarding the return loss MC55/56 provides the following values:
Table 20: Return loss
State of module Return loss of module Recommended return loss of application
Receive > 8dB > 12dB
Transmit not applicable > 12dB
Idle < 5dB not applicable
The connection of the antenna or other equipment must be decoupled from DC voltage.
4.1 Antenna installation
To suit the physical design of individual applications MC55/56 offers two alternative
approaches to connecting the antenna:
• Recommended approach: U.FL-R-SMT antenna connector from Hirose assembled on
the component side of the PCB (top view on MC55/56). See Chapter 4.1.2 for details.
• Antenna pad and grounding plane placed on the bottom side. See Chapter 4.1.1.
Antenna ground
Antenna pad
Figure 27: U.FL-R-SMT connector Figure 28: Antenna pad and GND plane
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The U.FL-R-SMT connector has been chosen as antenna reference point (ARP) for the
Siemens reference equipment submitted to type approve MC55/56. All RF data specified
throughout this manual are related to the ARP. For compliance with the test results of the
Siemens type approval you are advised to give priority to the connector, rather than using the
antenna pad.
IMPORTANT: Both solutions can only be applied alternatively. This means, whenever an
antenna is plugged to the Hirose connector, the pad must not be used. Vice versa, if the
antenna is connected to the pad, then the Hirose connector must be left empty.
Antenna connected to Hirose connector:
Module
Antenna or
measurement
PAD
50Ohm
U.FL
equipment
50Ohm
Antenna connected to pad:
Module
PAD
50Ohm
U.FL
Z
Z
ntenna o
measuremen
equipmen
50Ohm
Figure 29: Never use antenna connector and antenna pad at the same time
No matter which option you choose, ensure that the antenna pad does not come into contact
with the holding device or any other components of the host application. It needs to be
surrounded by a restricted area filled with air, which must also be reserved 0.8 mm in height.
U.FL antenna connector
RF section
PCB
ntenna pad
Figure 30: Restricted area around antenna pad
Restricted area
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4.1.1 Antenna pad
The antenna can be soldered to the pad, or attached via contact springs. To help you ground
the antenna, MC55/56 comes with a grounding plane located close to the antenna pad. The
positions of both pads can be seen from Figure 40.
When you decide to use the antenna pad take into account that the pad has not been
intended as antenna reference point (ARP) for the Siemens MC55/56 type approval. The
antenna pad is provided only as an alternative option which can be used, for example, if the
recommended Hirose connection does not fit into your antenna design.
Also, consider that according to the GSM recommendations TS 45.005 and TS 51.010-01 a
50 connector is mandatory for type approval measurements. This requires GSM devices
with an integral antenna to be temporarily equipped with a suitable connector or a low loss
RF cable with adapter.
To prevent damage to the module and to obtain long-term solder joint properties you are
advised to maintain the standards of good engineering practice for soldering.
MC55/56 material properties:
MC55/56 PCB: FR4
Antenna pad: Gold plated pad
4.1.1.1 Suitable cable types
For direct solder attachment, we suggest to use the following cable types:
• RG316/U 50 Ohm coaxial cable
• 1671A 50 Ohm coaxial cable
Suitable cables are offered, for example, by IMS Connector Systems. For further details and
other cable types please contact http://www.imscs.com
.
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4.1.2 Hirose antenna connector
MC55/56 uses an ultra-miniature SMT antenna connector
supplied from Hirose Ltd. The product name is:
U.FL-R-SMT
The position of the antenna connector on the MC55/56 board can
be seen in Figure 41.
Figure 31: Mechanical dimensions of U.FL-R-SMT connector
Table 21: Product specifications of U.FL-R-SMT connector
Item Specification Conditions
Ratings
s
Nominal impedance
Rated frequency DC to 6 GHz
Mechanical characteristics
Female contact holding
force
Repetitive operation Contact resistance:
Vibration No momentary disconnections of
Shock No momentary disconnections of
Environmental characteristics
Humidity resistance No damage, cracks and looseness
50 Ω
0.15 N min
Centre 25 mΩ
Outside 15mΩ
1 µs;
No damage, cracks and looseness
of parts
1 µs.
No damage, cracks and looseness
of parts.
of parts.
Insulation resistance:
100 MΩ min. at high humidity
500 MΩ min when dry
Operating temp: -40°C to +90°C
Operating humidity: max. 90%
Measured with a ∅ 0.475 pin
gauge
30 cycles of insertion and
disengagement
Frequency of 10 to 100 Hz,
single amplitude of 1.5 mm,
acceleration of 59 m/s2, for 5
cycles in the direction of each of
the 3 axes
Acceleration of 735 m/s2, 11 ms
duration for 6 cycles in the
direction of each of the 3 axes
Exposure to 40°C, humidity of
95% for a total of 96 hours
Temperature cycle No damage, cracks and looseness
of parts.
Contact resistance:
Centre 25 mΩ
Outside 15mΩ
Salt spray test No excessive corrosion 48 hours continuous exposure to
Temperature: +40°C → 5 to 35°C
→ +90°C → 5 to 35°C
Time: 30 min. → within 5 min. →
30 min. → within 5 min
5% salt water
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Table 22: Material and finish of U.FL-R-SMT connector and recommended plugs
Part Material Finish
Shell Phosphor bronze Silver plating
Male centre contact Brass Gold plating
Female centre contact Phosphor bronze Gold plating
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Insulator Plug: PBT
Receptacle: LCP
Black
Beige
Mating plugs and cables can be chosen from the Hirose U.FL Series. Examples are shown
below and listed in Table 23. For latest product information please contact your Hirose dealer
or visit the Hirose home page, for example http://www.hirose.com
.
Figure 32: U.FL-R-SMT connector with U.FL-LP-040 plug
Figure 33: U.FL-R-SMT connector with U.FL-LP-066 plug
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In addition to the connectors illustrated above, the U.FL-LP-(V)-040(01) version is offered as
an extremely space saving solution. This plug is intended for use with extra fine cable (up to
∅ 0.81 mm) and minimizes the mating height to 2 mm. See Figure 34 which shows the
Hirose datasheet.
Figure 34: Specifications of U.FL-LP-(V)-040(01) plug
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Table 23: Ordering information for Hirose U.FL Series
Item Part number HRS number
Connector on MC55/56 U.FL-R-SMT CL331-0471-0-10
Right-angle plug shell for
∅ 0.81 mm cable
Right-angle plug for
∅ 0.81 mm cable
Right-angle plug for
∅ 1.13 mm cable
Right-angle plug for
∅ 1.32 mm cable
Extraction jig E.FL-LP-N CL331-0441-9
U.FL-LP-040 CL331-0451-2
U.FL-LP(V)-040 (01) CL331-053-8-01
U.FL-LP-066 CL331-0452-5
U.FL-LP-066 CL331-0452-5
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5 Electrical, reliability and radio characteristics
5.1 Absolute maximum ratings
Absolute maximum ratings for supply voltage and voltages on digital and analog pins of
MC55/56 are listed in Table 24. Exceeding these values will cause permanent damage to
MC55/56.
Table 24: Absolute maximum ratings
Parameter Min Max Unit
Voltage BATT+ -0.3 4.8 V
Voltage at digital pins -0.3 3.3 V
Voltage at analog pins -0.3 3.0 V
Voltage at digital / analog pins in POWER DOWN mode -0.25 +0.25 V
Voltage at POWER pin 15 V
Voltage at CHARGE pin 15 V
Differential load resistance between EPNx and EPPx 15
Ω
5.2 Operating temperatures
Test conditions were specified in accordance with IEC 60068-2 (still air). The values stated
below are in compliance with GSM recommendation TS 51.010-01.
Table 25: Operating temperatures
Parameter Min Typ Max Unit
Ambient temperature (according to GSM 11.10) -20 25 55 °C
Restricted operation *) -25 to -20 55 to 70
Automatic shutdown
MC55/56 board temperature
Battery temperature
Charging temperature (software controlled fast charging) 0 +45 °C
*)
MC55/56 works, but deviations from the GSM specification may occur.
**)
MC55/56 has the automatic shutdown set to 70°C at PCL5 (GSM 900 / GSM 850) GPRS Class
8. This prevents permanent damage to components on the board. Consider the ratio of output
power, supply voltage and operating temperature: To achieve T
GSM 900 / GSM 850 PCL5 the supply voltage must not be higher than 4.2V.
***)
To achieve T
GSM 850 at PCL5 with a supply voltage 4.2V) it is recommended to integrate MC55/56 in such
a way that a minor heat exchange with the environment can take place. A solution might be the
usage of a small heat sink.
= 70°C at permanent GPRS class 8 operation (4Tx, 1Rx, GSM 900 /
amb max
-29
-18
>70
>60
= 70°C and, for example,
amb max
***)
°C
**)
°C
°C
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5.3 Electrical specifications of the application interface
Please note that the reference voltages listed in Table 26 are the values measured directly
on the MC55/56 module. They do not apply to the accessories connected.
If an input pin is specified for V
value 3.3V is an absolute maximum rating.
The Hirose DF12C board-to-board connector on MC55/56 is a 50-pin double-row receptacle.
The names and the positions of the pins can be seen from Figure 35 which shows the top
view of MC55/56.
26
50
BATT+ GND
BATT+ GND
BATT+ GND
BATT+ GND
BATT+ GND
VDD CHARGE
/RING0 POWER
/DSR0 VDDLP
/RTS0 /TXD0
/DTR0 /TXD1
/RTS1 /RXD0
/CTS0 /RXD1
/CTS1 SYNC
/DCD0 BATT_TEMP
/EMERGOFF RFSDAI
/IGT TXDDAI
GND SCLK
MICN1 TFSDAI
MICP1 RXDDAI
MICP2 CCGND
MICN2 CCIN
EPN1 CCRST
EPP1 CCIO
EPP2 CCVCC
EPN2 CCCLK
= 3.3V, be sure never to exceed the stated voltage. The
i,h,max
25
1
Figure 35: Pin assignment (top view on MC55/56)
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Table 26: Electrical description of application interface
Function Signal name IO Signal form and level Comments
Power
supply
Charge
interface
External
supply
voltage
VDD Low
Power
BATT+ I VI = 3.3V to 4.8V
V
norm = 4.2V
I
Inorm 1.6A during Tx burst
GND
1 Tx, peak current 577µs every 4.616ms
2 Tx, peak current 1154µs every 4.616ms
POWER I
V
min = 3.0V
I
V
max = 15V
I
BATT_TEMP I
Connect NTC with R
ground.
CHARGE O
VDD O
I
= -300µA ... -600µA
CHARGE
@ 3V < V
CHARGE
VDDmin = 2.84V, VDDmax = 2.96V
Imax = -10mA
C
max = 1µF
L
VDDLP I/O
R
=1kΩ
I
V
max 4.0V (output)
O
V
min = 2.2V, VImax = 5.5V (input)
I
I
typ = 10µA at BATT+ = 0V
I
Mobile in POWER DOWN mode:
VImin = 1.2V
10kΩ @ 25°C to
NTC
< V
LOAD
Power supply input.
5 BATT+ pins to be
connected in parallel.
5 GND pins to be
connected in parallel.
The power supply must be
able to meet the
requirements of current
consumption in a Tx burst
(up to 2A).
Sending with two timeslots
doubles the duration of
current pulses to 1154µs
(every 4.616ms)!
This line signalises to the
processor that the charger
is connected.
If unused keep pin open.
Input to measure the
battery temperature over
NTC resistor.
NTC should be installed
inside or near battery pack
to enable the charging
algorithm and deliver
temperature values.
If unused keep pin open.
This line is a current source
for the charge FET with a
10kΩ resistance between
gate and source.
If unused keep pin open.
Supply voltage, e.g. for an
external LED or level
shifter. The external digital
logic must not cause any
spikes or glitches on
voltage VDD.
Not available in POWER
DOWN mode.
VDD signalises the “ON”
state of the module.
If unused VDD keep pin
open.
Supplies the RTC with
power via an external
capacitor or buffer battery if
no V
BATT+
If unused keep pin open.
is applied.
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Function Signal name IO Signal form and level Comments
Ignition /IGT I
R
V
V
I
IL
Open
ON
Emergency
shutdown
(Watchdog)
/EMERGOFF I/O
R
V
V
I
IL
Open
Signal
Watchdog:
V
OL
V
OH
f
O
f
O
Synchronization
SYNC O
VOLmax = 0.2V at I = 1mA
V
OH
V
OH
1 Tx, 877µs impulse each 4.616ms and
2 Tx, 1454µs impulse each 4.616ms, with
300µs forward time.
100kΩ, CI 1nF
max = 0.5V at Imax = -20µA
max = 2.3V
~~~
|____|
~~~
Active Low ≥ 100ms
22kΩ
max = 0.5V at Imax = -100µA
max = 2.73V
~~~
|______|
~~~
Active Low ≥ 3.2s
max = 0.35V at I = 10µA
min= 2.25V at I = -10µA
min = 0.16Hz
max = 1.55Hz
min = 2.35V at I = -1mA
max = 2.73V
Input to switch the mobile
ON.
The line must be driven low
by an Open Drain or Open
Collector driver.
This line must be driven by
an Open Drain or Open
Collector driver.
Emergency shutdown
deactivates the power
supply to the module.
The module can be reset if
/IGT is activated after
emergency shutdown.
To switch the mobile off
use the AT^SMSO
command.
To avoid floating if pin is
high impedance, use pulldown resistor tied to GND.
See Chapter 3.3.2.1.
/EMERGOFF also
indicates the internal
watchdog function.
If unused keep pin open.
Indicates increased current
consumption during uplink
transmission burst. Note
that timing is different
during handover.
Alternatively used to
control status LED (see
Chapter 3.12.2.2).
If unused keep pin open.
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Function Signal name IO Signal form and level Comments
SIM interface
ASC0
interface
ASC1
interface
Digital audio
interface
CCIN I
CCRST O
CCIO I/O
R
100kΩ
I
V
max = 0.5V
IL
V
min = 2.15V at I = 20µA,
IH
V
max=3.3V at I = 30µA
IH
R
47Ω
O
V
max = 0.25V at I = 1mA
OL
V
min = 2.3V at I = -1mA
OH
V
max = 2.73V
OH
R
10kΩ
I
V
max = 0.5V
IL
V
min = 1.95V, VIHmax=3.3V
IH
RO 220Ω
V
max = 0.4V at I = 1mA
OL
V
min = 2.15V at I = -1mA
OH
V
min = 2.55V at I = -20µA
OH
V
max = 2.96V
OH
CCCLK O
CCVCC O
R
220Ω
O
V
max = 0.4V at I = 1mA
OL
V
min = 2.15V at I = -1mA
OH
V
max = 2.73V
OH
R
max = 5Ω
O
CCVCCmin = 2.84V,
CCVCCmax = 2.96V
Imax = -20mA
CCGND Ground
/RXD0 O
/TXD0 I
/CTS0 O
/RTS0 I
/DTR0 I
/DCD0 O
/DSR0 O
max = 0.2V at I = 1mA
V
OL
V
min = 2.35V at I = -1mA
OH
V
max = 2.73V
OH
VILmax = 0.5V
V
min = 1.95V, VIHmax=3.3V
IH
/DTR0, RTS0: Imax = -90µA at V
/TXD0: Imax = -30µA at V
/RING0 O
/RXD1 O
/TXD1 I
/CTS1 O
/RTS1 I
RFSDAI I
RXDDAI I
SCLK I
TFSDAI O
TXDDAI O
max = 0.2V at I = 1mA
V
OL
V
min = 2.35V at I = -1mA
OH
V
max = 2.73V
OH
V
max = 0.5V
IL
V
min = 1.95V, VIHmax=3.3V
IH
max = -90µA at VIN = 0V
I
I
VOLmax = 0.2V at I = 1mA
V
min = 2.35V at I = -1mA
OH
V
max = 2.73V
OH
VILmax = 0.5V
V
min = 1.95V, VIHmax=3.3V
IH
I
max = 330µA at VIN = 3.3V
I
= 0V
IN
= 0V
IN
CCIN = high, SIM card
holder closed (no card
recognition)
Maximum cable length
200mm to SIM card holder.
All signals of SIM interface
are protected against ESD
with a special diode array.
Usage of CCGND is
mandatory.
First serial interface for AT
commands or data stream.
To avoid floating if output
pins are high-impedance,
use pull-up resistors tied to
VDD or pull-down resistors
tied to GND. See Chapter
3.3.2.1.
If unused keep pins open.
Second serial interface for
AT commands.
To avoid floating if output
pins are high-impedance,
use pull-up resistors tied to
VDD or pull-down resistors
tied to GND. See Chapter
3.3.2.1.
If unused keep pins open.
If unused keep pins open.
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Function Signal name IO Signal form and level Comments
Analog audio
interfaces
Explanation of signal names:
P = positive, N = negative
EPP2 O
EPN2 O
EPP1 O
EPN1 O
MICP1 I
MICN1 I
MICP2 I
MICN2 I
AGND Separate ground
VOmax = 3.7Vpp
See also Table 30.
VOmax = 3.7Vpp
See also Table 30.
RI 50kΩ differential
V
max = 1.03Vpp
I
See also Table 31.
RI = 2kΩ differential
V
max = 1.03Vpp
I
See also Table 31.
The audio output is
balanced and can directly
operate an earpiece.
If unused keep pins open.
Balanced audio output.
Can be used to directly
operate an earpiece.
If unused keep pins open.
Balanced microphone
input. To be decoupled with
2 capacitors (C
if connected to a
microphone or another
device.
If unused keep pins open.
Balanced microphone
input. Can be used to
directly feed an active
microphone.
If used for another signal
source, e.g. op amp, to be
decoupled with capacitors.
If unused keep pins open.
connection for external
audio circuits.
= 100nF),
K
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5.4 Power supply ratings
Table 27: Power supply ratings
Parameter Description Conditions Min Typ Max Unit
BATT+
I
BATT+
Supply voltage Reference points on MC55/56:
TP BATT+ and TP GND (see
Figure 40). Voltage must stay
within the min/max values,
including voltage drop, ripple,
spikes.
Voltage drop during
transmit burst
Normal condition, power control
level for P
out max
Voltage ripple Normal condition, power control
level for P
out max
@ f<200kHz
@ f>200kHz
Average supply
current3)
POWER DOWN mode 50 100 µA
SLEEP mode @ DRX = 6 3 mA
IDLE mode GSM850
EGSM 900
GSM 1800/1900
TALK mode GSM850
EGSM 900
GSM 1800/1900
1) 4)
1) 4)
3.3 4.2 4.8 V
400 mV
mV
50
2
15
mA
15
15
2) 4)
260
260
180
mA
Peak supply current
(during transmission
slot every 4.6ms)
1)
Power control level PCL 5
2)
Power control level PCL 0
3)
All average supply current values @ I
4)
Test conditions: 50 Ω
IDLE GPRS GSM850
EGSM 900
GSM 1800/1900
DATA mode GPRS,
(4 Rx, 1 Tx) E GSM850
GSM 900
GSM 1800/1900
DATA mode GPRS,
(3 Rx, 2 Tx) GSM850
EGSM 900
GSM 1800/1900
1) 4)
1) 4)
1) 4)
1) 4)
2) 4)
2) 4)
Power control level 1)
= 0mA
VDD
15
mA
15
15
300
mA
300
230
450
mA
450
330
1.6 A
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5.4.1 Current consumption during transmit burst
The diagrams provided in Figure 36 and Figure 37 illustrate the typical current consumption
of the application caused during a transmit burst. The typical peak current is shown vs. the
power control level for 900 MHz, 1800 MHz and 1900 MHz and vs. the return loss of the
antenna.
Test conditions: All measurements have been performed at T
Reference points for measuring the voltage are the BATT+ and GND test points on the back
side of the module. The curves are for one TX slot (for example a voice call, CSD call or
Class 8 GPRS). Curves for Class 10 GPRS activities (2 TX slots) are shown too.
Changing the conditions, e.g. in terms of temperature or voltage, will cause different results.
= 25°C, V
amb
BATT+ nom
= 4.1V.
Average Current GSM900 (V
0.5
0.45
0.4
0.43
0.35
0.3
0.25
0.25
Current (Amps)
0.2
0.15
0.1
0.05
0
5 7 9 11 13 15 17 19
0.33
0.23
0.21
0.15
Power Control Level
BATT+
0.16
0.11
=4.1V)
1 TX - Average Current
2 TX - Average Current
0.14
0.10
0.13
0.10
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Average Current DCS1800 (V
0.3
0.25
0.26
0.2
0.19
0.18
0.15
Current (Amps)
0.1
0.05
0
0123456789101112131415
0.13
0.16
0.12
Power Control Level
BATT+
=4.1V)
1 TX - Average Current
2 TX - Average Current
0.14
0.10
0.13
0.10
Average Current PCS1900 (V
0.3
0.29
0.25
0.2
0.17
0.15
Current (A mps)
0.1
0.05
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
0.21
0.17
0.13
0.12
Power Control Level
BATT+
=4.1V)
1 TX - Average Current
2 TX - Average Current
0.14
0.11
0.13
0.10
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Burst Current GSM900 (V
1.8
1.6
1.6
1.4
1.2
1
0.8
Current (Amps)
0.6
0.4
0.2
0
5 7 9 11 13 15 17 19
1.24
0.68
Power Control Level
BATT+
0.4
=4.1V)
1 TX - Peak current
0.3
0.28
Burst Current DCS1800 (V
1
0.9
0.8
0.84
0.7
0.6
0.5
Current (Amps)
0.4
0.3
0.2
0.1
0
0123456789101112131415
0.52
0.38
Power Control Level
BATT+
=4.1V)
0.27
1 TX - Peak current
0.24
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Burst Current PCS1900 (V
1
0.92
0.9
0.8
0.7
0.6
0.5
Current (Amps)
0.4
0.3
0.2
0.1
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
0.6
0.42
Test conditions: T
Power Control Level
= 25°C, V
amb
=4.1V)
BATT+
BATT+ nom
1 TX - Peak current
0.3
= 4.1V
Figure 36: Typical current consumption vs. power control level
0.24
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1600
s
1400
1200
1000
800
Current (mA)
600
400
200
1000
Service mode GSM900 ch.124
ariations in current with 0.4dB return
loss (all phases)
ch.124 PCL5
0
Burst (max) Burst (min) Average Current (Max) Average Current (Min)
900
800
700
600
500
Current (mA)
400
300
200
100
0
Burst (max) Burst (min) Average Current (Max) Average Current (Min)
Test conditions: T
= 25°C, V
amb
BATT+ nom
Service mode PCS1900 ch.661
ariations in current with 0.6dB return
loss (all phases)
ch.661 PCL0
= 4.1V measured at TP BATT+ and GND, 1 TX slot
Figure 37: Typical current consumption vs. return loss
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5.5 Electrical characteristics of the voiceband part
5.5.1 Setting audio parameters by AT commands
The audio modes 2 to 6 can be adjusted according to the parameters listed below. Each
audio mode is assigned a separate set of parameters.
Table 28: Audio parameters adjustable by AT command
Parameter Influence to Range Gain range Calculation
inBbcGain MICP/MICN analog amplifier gain of
baseband controller before ADC
inCalibrate digital attenuation of input signal
after ADC
outBbcGain EPP/EPN analog output gain of
baseband controller after DAC
outCalibrate[n]
n = 0...4
sideTone digital attenuation of sidetone
digital attenuation of output signal
after speech decoder, before
summation of sidetone and DAC
present for each volume step[n]
is corrected internally by
outBbcGain to obtain a constant
sidetone independent of output
volume
0...7 0...42dB 6dB steps
0...32767 -...0dB 20 * log
(inCalibrate/
32768)
0...3 0...-18dB 6dB steps
0...32767 -...+6dB 20 * log (2 *
outCalibrate[n]/
32768)
0...32767 -...0dB 20 * log
(sideTone/
32768)
Note: The parameters inCalibrate, outCalibrate and sideTone accept also values from 32768
to 65535. These values are internally truncated to 32767.
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5.5.2 Audio programming model
The audio programming model shows how the signal path can be influenced by varying the
AT command parameters. The model is the same for all three interfaces, except for the
parameters <outBbcGain> and <inBbcGain> which cannot be modified if the digital audio
interface is being used, since in this case the DAC is switched off.
The parameters inBbcGain and inCalibrate can be set with AT^SNFI. All the other
parameters are adjusted with AT^SNFO.
MIC1
MIC2
RFSD AI, RXDDAI
TFSDAI, TXDDAI
2.65V
1k
1k
10uF
1k
1k
<outBbcGain>
neg. gain (attenuation)
0dB; -6db, -12dB; -18dB
<mic>
<inBbcGain>
+0...42dB in 6dB steps
<ep>
<inCalibrate>
A
D
D
A
-∞...0dB
<io>
Speech coder
<sideTone>
+
<outCalibrate[n]>
T parameters are given in brackets <…>
and marked red and italic.
Speech decoder
n = 0...4
Figure 38: Audio programming model
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5.5.3 Characteristics of audio modes
The electrical characteristics of the voiceband part depend on the current audio mode set
with the AT^SNFS command.
Table 29: Voiceband characteristics (typical)
Audio mode no.
AT^SNFS=
1 (Default
settings, not
2 3 4 5 6
adjustable)
Name Default
Handset
Purpose DSB with
Votronic
handset
Gain setting via AT
command. Defaults:
inBbcGain
outBbcGain
Default audio
Fix
4 (24dB)
1 (-6dB)
1 2 2 1 1 2 3)
Basic
Handsfree
Siemens Car
Kit Portable
Adjustable
2 (12dB)
1 (-6dB)
Headset User
Handset
Siemens
Headset
DSB with
individual
handset
Adjustable
5 (30dB)
2 (-12dB)
Adjustable
4 (24dB)
1 (-6dB)
Plain
Codec 1
Direct
access to
speech
coder
Adjustable
0 (0dB)
0 (0dB)
Plain
Codec 2
Direct
access to
speech
coder
Adjustable
0 (0dB)
0 (0dB)
interface
Power supply
ON (2.65V) ON (2.65V) ON (2.65V) ON (2.65V) OFF (GND) OFF (GND)
Sidetone ON --- Adjustable Adjustable Adjustable Adjustable
Volume control OFF Adjustable Adjustable Adjustable Adjustable Adjustable
Limiter (receive) ON ON ON ON --- ---
Compressor
--- OFF1) --- --- --- ---
(receive)
AGC (send) --- --- ON --- --- ---
Echo control (send) Suppression Cancellation +
suppression
--- Suppression
--- ---
Noise suppression2) --- up to 10dB 10dB --- --- ---
MIC input signal for
0dBm0 @ 1024 Hz
(default gain)
EP output signal in
mV rms. @ 0dBm0,
1024 Hz, no load
(default gain);
@ 3.14 dBm0
Sidetone gain at
default settings
23mV 58mV 7.5mV @
-3dBm0 due
to AGC
284mV 120mV
default @
max volume
300mV
default @
max volume
22.8dB - dB Affected by
AGC, 13dB
23mV 315mV 315mV
284mV
default @
max
volume
22.8dB
895mV
3.7Vpp
- dB - dB
895mV
3.7Vpp
@ 7.5mV
1)
Adaptive, receive volume increases with higher ambient noise level. The compressor can be
activated by loading an application specific audio parameter set (see [9]).
2)
In audio modes with noise reduction, the microphone input signal for 0dBm0 shall be measured
(MIC)
with a sine burst signal for a tone duration of 5 seconds and a pause of 2 sec. The sine signal
appears as noise and, after approx. 12 sec, is attenuated by the noise reduction by up to 10dB.
3)
Audio mode 5 and 6 are identical. With AT^SAIC, you can easily switch mode 5 to the second
interface. Therefore, audio mode 6 is only kept for compatibility to earlier Siemens GSM products.
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Note: With regard to acoustic shock, the cellular application must be designed to avoid
sending false AT commands that might increase amplification, e.g. for a high
sensitive earpiece. A protection circuit should be implemented in the cellular
application.
5.5.4 Voiceband receive path
Test conditions:
• The values specified below were tested to 1kHz and 0dB gain stage, unless otherwise
stated.
• Parameter setup: gs = 0dB means audio mode = 5 for EPP1 to EPN1 and 6 for EPP2 to
EPN2, inBbcGain= 0, inCalibrate = 32767, outBbcGain = 0, OutCalibrate = 16384,
sideTone = 0.
Table 30: Voiceband receive path
Parameter Min Typ Max Unit Test condition / remark
Differential output
voltage (peak to peak)
Differential output gain
settings (gs) at 6dB
stages (outBbcGain)
Fine scaling by DSP
(outCalibrate)
Output differential
DC offset
Differential output
resistance
Differential load
capacitance
Absolute gain accuracy 0.8 dB Variation due to change in
Attenuation distortion 1 dB for 300...3900Hz,
3.33 3.7 4.07 V from EPPx to EPNx
gs = 0dB @ 3.14 dBm0
no load
-18 0 dB Set with AT^SNFO
- 0 dB Set with AT^SNFO
100 mV gs = 0dB, outBbcGain = 0 and -6dB
2 from EPPx to EPNx
1000 pF from EPPx to EPNx
temperature and life time
@ EPPx/EPNx (333Hz) /
@ EPPx/EPNx (3.66kHz)
Out-of-band
discrimination
60 dB for f > 4kHz with in-band test
signal@ 1kHz and 1kHz RBW
gs = gain setting
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5.5.5 Voiceband transmit path
Test conditions:
• The values specified below were tested to 1kHz and 0dB gain stage, unless otherwise
stated.
• Parameter setup: Audio mode = 5 for MICP1 to MICN1 and 6 for MICP2 to MICN2,
inBbcGain= 0, inCalibrate = 32767, outBbcGain = 0, OutCalibrate = 16384, sideTone = 0
Table 31: Voiceband transmit path
Parameter Min Typ Max Unit Test condition/Remark
Input voltage (peak to peak)
MICP1 to MICN1, MICP2 to
MICN2
Input amplifier gain in 6dB steps
(inBbcGain)
Fine scaling by DSP (inCalibrate) - 0 dB Set with AT^SNFI
Input impedance MIC1 50 k
Input impedance MIC2 2.0 k
Microphone supply voltage ON
Ri = 4k (MIC2 only)
Microphone supply voltage OFF;
Ri = 4k (MIC2 only)
Microphone supply in POWER
DOWN mode
1.03 V
0 42 dB Set with AT^SNFI
2.57
2.17
1.77
0 V
See Figure 17
2.65
2.25
1.85
2.73
2.33
1.93
V
V
V
no supply current
@ 100µA
@ 200µA
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5.6 Air interface
s
Test conditions: All measurements have been performed at T
= 25°C, V
amb
BATT+ nom
= 4.1V.
The reference points used on MC55/56 are the BATT+ and GND contacts (test points are
shown in Figure 40).
Table 32: Air Interface
Parameter Min Typ Max Unit
Frequency range
Uplink (MS → BTS)
Frequency range
Downlink (BTS → MS)
RF power @ ARP with 50 load
GSM 850 3) 824 849 MHz
E-GSM 900 4) 880 915 MHz
GSM 1800 1710 1785 MHz
GSM 1900 1850 1910 MHz
GSM 850 3) 869 894 MHz
E-GSM 900 4) 925 960 MHz
GSM 1800 1805 1880 MHz
GSM 1900 1930 1990 MHz
GSM 850 3) 31 33 35 dBm
E-GSM 900
4) 1)
31 33 35 dBm
GSM 1800 2) 28 30 32 dBm
GSM 1900 28 30 32 dBm
Number of carriers
GSM 850 3) 124
E-GSM 900 4) 174
GSM 1800 374
GSM 1900 299
Duplex spacing
GSM 850 3) 45 MHz
E-GSM 900 4) 45 MHz
GSM 1800 95 MHz
GSM 1900 80 MHz
Carrier spacing 200 kHz
Multiplex, Duplex TDMA / FDMA, FDD
Time slots per TDMA frame 8
Frame duration 4.615 ms
Time slot duration 577 µs
Modulation GMSK
Receiver input sensitivity @ ARP
BER Class II < 2.4% (static input level)
GSM 850 3) -102 -107 dBm
E-GSM 900 4) -102 -107 dBm
GSM 1800 -102 -106 dBm
GSM 1900 -102 -105.5 dBm
1)
Power control level PCL 5
2)
Power control level PCL 0
3)
MC56 only 4) MC55 only
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5.7 Electrostatic discharge
The GSM engine is not protected against Electrostatic Discharge (ESD) in general.
Consequently, it is subject to ESD handling precautions that typically apply to ESD sensitive
components. Proper ESD handling and packaging procedures must be applied throughout
the processing, handling and operation of any application that incorporates a MC55/56
module.
Special ESD protection provided on MC55/56:
Antenna interface: one spark discharge line (spark gap)
SIM interface: clamp diodes for protection against overvoltage.
The remaining ports of MC55/56 are not accessible to the user of the final product (since
they are installed within the device) and therefore, are only protected according to the
“Human Body Model” requirements.
MC55/56 has been tested according to the EN 61000-4-2 standard. The measured values
can be gathered from the following table.
Table 33: Measured electrostatic values
Specification / Requirements Contact discharge Air discharge
ETSI EN 301 489-7
ESD at SIM port
ESD at antenna port
Human Body Model (Test conditions: 1.5 kΩ, 100 pF)
ESD at the module
± 4kV ± 8kV
± 4kV ± 8kV
± 1kV
Note: Please note that the values may vary with the individual application design. For
example, it matters whether or not the application platform is grounded over external
devices like a computer or other equipment, such as the Siemens reference
application described in Chapter 7.
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5.8 Reliability characteristics
The test conditions stated below are an extract of the complete test specifications.
Table 34: Summary of reliability test conditions
Type of test Conditions Standard
Vibration Frequency range: 10-20 Hz; acceleration: 3.1mm
amplitude
Frequency range: 20-500 Hz; acceleration: 5g
Duration: 2h per axis = 10 cycles; 3 axes
Shock half-sinus Acceleration: 500g
Shock duration: 1msec
1 shock per axis
6 positions (± x, y and z)
Dry heat Temperature: +70 ±2°C
Test duration: 16 h
Humidity in the test chamber: < 50%
Temperature
change (shock)
Damp heat cyclic High temperature: +55°C ±2°C
Low temperature: -40°C ±2°C
High temperature: +85°C ±2°C
Changeover time: < 30s (dual chamber system)
Test duration: 1 h
Number of repetitions: 100
DIN IEC 68-2-6
DIN IEC 68-2-27
EN 60068-2-2 Bb ETS
300019-2-7
DIN IEC 68-2-14 Na
ETS 300019-2-7
DIN IEC 68-2-30 Db
Cold (constant
exposure)
Low temperature: +25°C ±2°C
Humidity: 93% ±3%
Number of repetitions: 6
Test duration: 12h + 12h
Temperature: -40 ±2°C
Test duration: 16 h
ETS 300019-2-5
DIN IEC 68-2-1
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6 Mechanics
The following chapters describe the mechanical dimensions of MC55/56 and give
recommendations for integrating MC55/56 into the host application.
6.1 Mechanical dimensions of MC55/56
Figure 39 shows the top view on MC55/56 and provides an overview of the mechanical
dimensions of the board. For further details see Figure 41.
Size: 35±0.15 x 32.5±0.15 x 3.1±0.3 mm (including application connector)
35±0.15 x 32.5±0.15 x 2.95±0.2 mm (excluding application connector)
Weight: 5.5g
Figure 39: MC55/56 – top view
Figure 40 shows the bottom view of MC55/56 and marks the test points and pads for
antenna connection.
Antenna ground
TP BATT+
TP Ground
Figure 40: MC55/56 bottom view
Antenna pad
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2.4
1.5
2.6
0.15
±
35.0
±
0.3
3.10
All dimensions in millimetres
32.5
2.0
9.5
1)
0.5
12.3
ø
±0.15
+0.1
2.05
30.5
+0.01
-0.04
Identification
label
3.2
Board-to-board
connector
2)
2.0
14.6
R1.0
s
4.6
Antenna pad
Ground
+
0.1
0.85
TP BATT+
TP Ground
16.3
6.3
±
0.2
2.95
1) max. ø 3 mm mounting area
2) max. ø 3.2 mm mounting area
5.3
6.1
3.2
1.1
1.1
1.6
6.6
1.4
1.9
5.8
Position
2D Barcode
3.8
7.7
2.3
Figure 41: Mechanical dimensions of MC55/56
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6.2 Mounting MC55/56 onto the application platform
There are many ways to properly install MC55/56 in the host device. An efficient approach is
to mount the MC55/56 PCB to a frame, plate, rack or chassis.
Fasteners can be M1.6 or M1.8 screws plus suitable washers, circuit board spacers, or
customized screws, clamps, or brackets. Screws must be inserted with the screw head on
the bottom of the MC55/56 PCB. In addition, the board-to-board connection can also be
utilized to achieve better support.
Particular attention must be paid to the holes marked with an arrow in Figure 42. Both holes
are close to other components of MC55/56 and care must be taken to avoid contacting them.
For example, you can insert plastic screws and plastic washers, or fasteners small enough
not to protrude beyond the mounting areas specified in Figure 41.
Figure 42: Mounting holes on MC55/56
For proper grounding it is strongly recommended to use the ground plane on the back side in
addition to the five GND pins of the board-to-board connector. To avoid short circuits ensure
that the remaining sections of the MC55/56 PCB do not come into contact with the host
device since there are a number of test points. Figure 40 shows the positions of all test
points.
To prevent mechanical damage, be careful not to force, bend or twist the module. Be sure it
is positioned flat against the host device.
All the information you need to install an antenna is summarized in Chapter 4.1. Note that the
antenna pad on the bottom of the MC55/56 PCB must not be influenced by any other PCBs,
components or by the housing of the host device. It needs to be surrounded by a restricted
space as described in Chapter 4.1.
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6.3 Board-to-board connector
This chapter provides specifications for the 50-pin board-to-board connector which serves as
physical interface to the host application. The receptacle assembled on the MC55/56 PCB is
type Hirose DF12C. Mating headers from Hirose are available in different stacking heights.
Figure 43: Hirose DF12C receptacle on MC55/56
Table 35: Ordering information DF12 series
Figure 44: Header Hirose DF12 series
Item Part number Stacking
HRS number
height (mm)
Receptacle on MC55/56 DF12C(3.0)-50DS-0.5V(81) 3 - 5 537-0694-9-81
Headers DF12 series DF12E(3.0)-50DP-0.5V(81)
DF12E(3.5)-50DP-0.5V(81)
DF12E(4.0)-50DP-0.5V(81)
DF12E(5.0)-50DP-0.5V(81)
3.0
3.5
4.0
5.0
537-0834-6-**
537-0534-2-**
537-0559-3-**
537-0584-0-**
Notes: The headers listed above are without boss and metal fitting. Please contact Hirose for details
on other types of mating headers. Asterixed HRS numbers denote different types of packaging.
Table 36: Electrical and mechanical characteristics of the Hirose DF12C connector
Parameter Specification (50 pin board-to-board connector)
Number of contacts 50
Quantity delivered 2000 connectors per tape & reel
Voltage 50V
Rated current 0.3A max per contact
Resistance 0.05 Ohm per contact
Dielectric withstanding voltage 500V RMS min
Operating temperature -45°C...+125°C
Contact material phosphor bronze (surface: gold plated)
Insulator material PA , beige natural
Stacking height 3.0 mm ; 3.5 mm ; 4.0 mm ; 5.0 mm
Insertion force 21.8N
Withdrawal force 1
Withdrawal force 50
st
10N
th
10N
Maximum connection cycles 50
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6.3.1 Mechanical dimensions of the Hirose DF12 connector
Figure 45: Mechanical dimensions of Hirose DF12 connector
6.3.2 Adapter cabling
The board-to-board connection is primarily intended for direct contact between both
connectors. If this assembly solution does not fit into your application design ensure that the
used adapter cable meets the following requirements:
• Maximum length: 200 mm
It is recommended that the total cable length between the board-to-board connector pins
on MC55/56 and the pins of the card holder does not exceed 200 mm in order to meet
the specifications of 3GPP TS 51.010-1 and to satisfy the requirements of EMC
compliance.
• Type of cable: Flexible cable or flexible printed circuit board designed to mate with the
Hirose receptacle and headers specified above.
The equipment submitted for type approving the Siemens reference setup of MC55/56
includes a 160mm adapter cable. See Chapter 7.1.
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7 Reference Approval
7.1 Reference Equipment for Type Approval
The Siemens reference setup submitted to type approve MC55/56 consists of the following
components:
• Siemens MC55/56 cellular engine
• Development Support Box (DSB45)
• Flex cable (160 mm) from Hirose DF12C receptacle on MC55/56 to Hirose DF12
connector on DSB45. Please note that this cable is not included in the scope of delivery
of DSB45.
• SIM card reader integrated on DSB45
• Handset type Votronic HH-SI-30.3/V1.1/0
• PC as MMI
ntenna or 50 Ω
cable to system
simulator
ntenna
PC
Power supply
RS-232
Figure 46: Reference equipment for approval
DSB45
Flex cable
160mm
DAI cable for
acoustic measuring
SIM
Handset
coustic tester
GSM engine
DAI Box
MC55/56_hd_v02.06 Page 99 of 105 29.10.2004
MC55/56 Hardware Interface Description
Confidential / Released
s
7.2 Compliance with FCC Rules and Regulations (MC55 only)
The FCC Equipment Authorization Certification for the MC55 reference application described
in Chapter 7.1 is listed under the
FCC identifier QIPMC55
IC: 267W-MC55
granted to Siemens AG.
The MC55 reference application registered under the above identifier is certified to be in
accordance with the following Rules and Regulations of the Federal Communications
Commission (FCC).
“This device contains GSM 900 MHz and GSM 1800MHz functions that are not
operational in U.S. Territories.
This device is to be used only for mobile and fixed applications. The antenna(s) used
for this transmitter must be installed to provide a separation distance of at least 20 cm
from all persons and must not be co-located or operating in conjunction with any other
antenna or transmitter. Users and installers must be provided with antenna installation
instructions and transmitter operating conditions for satisfying RF exposure compliance. Antennas used for this OEM module must not exceed 7dBi gain for mobile and
fixed operating configurations. This device is approved as a module to be installed in
other devices. Each OEM must obtain their own Certification for each device containing
this module.”
IMPORTANT: Manufacturers of mobile or fixed devices incorporating MC55 modules are
advised to
• clarify any regulatory questions,
• have their completed product tested,
• have product approved for FCC compliance, and
• include instructions according to above mentioned RF exposure statements in end
product user manual.
MC55/56_hd_v02.06 Page 100 of 105 29.10.2004
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