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hardware design SIM548_hd_v1.01
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 2 document title: SIM548 hardware design version: 1.01 date: 2007-02-07 status: release document control id: SIM548_hd_v1.01 general notes simcom offers this information as a service to its customers, to support application and engineering efforts that use the products designed by simcom. the information provided is based upon requirements specifically provided to simcom by the customers. simcom has not undertaken any independent search for additi onal relevant information, including any information that may be in the customer?s po ssession. furthermore, system validation of this product designed by simcom within a larger el ectronic system remains the responsibility of the customer or the customer?s system inte grator. all specifications supplied herein are subject to change. copyright this document contains proprietary technical information which is the property of simcom limited., copying of this document and giving it to others and the using or communication of the contents thereof, are forbidden without express authority. offenders are liable to the payment of damages. all rights reserved in the event of grant of a patent or the registration of a utility model or design. all specification supp lied herein are subject to change without notice at any time. copyright ? simcom limited. 2007
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 3 contents contents ....................................................................................................................... .....................3 version history................................................................................................................ .................7 1 introduction................................................................................................................. ...................8 1.1 related documents .......................................................................................................... .....8 1.2 terms and ab breviations .................................................................................................... ..9 2 product concept.............................................................................................................. ..............12 2.1 SIM548 key featur es at a glance ........................................................................................13 3 gsm application interface .................................................................................................... .......16 3.1 pin description............................................................................................................ ........16 3.2 operating modes ............................................................................................................ ....19 3.3 power supply............................................................................................................... .......20 3.3.1 power supply pins on the board-to-board connector ................................................21 3.3.2 minimizing power losses..........................................................................................21 3.3.3 monitoring power supply .........................................................................................22 3.4 power up and down scenarios ............................................................................................22 3.4.1 turn on the gsm part of SIM548 ............................................................................22 3.4.2 turn off the gsm part of SIM548 ...........................................................................25 3.4.3 restart the gsm part of si m548 using the pwrkey pin ......................................28 3.5 charging interface ......................................................................................................... .....28 3.5.1 battery pack characteristics......................................................................................29 3.5.2 recommended battery pack .....................................................................................30 3.5.3 implemented charging technique..............................................................................30 3.5.4 operating mode s during charging ............................................................................31 3.5.5 charger requirements ...............................................................................................33 3.6 power saving ............................................................................................................... .......33 3.6.1 minimum functionality mode...................................................................................33 3.6.2 sleep mode (slow clock mode)..............................................................................34 3.6.3 wake up the gsm part of SIM548 from sleep mode ...........................................34 3.7 summary of state transiti ons (except sleep mode) .........................................................35 3.8 rtc backup................................................................................................................. .......36 3.9 gsm serial interface....................................................................................................... ...40 3.9.1 function of serial por t & debug port supporting ......................................................41 3.9.2 software upgrade and software debug.....................................................................42 3.10 audio interfaces .......................................................................................................... .....44 3.10.1 speaker interface configuration..............................................................................45 3.10.2 microphone interf aces configuration......................................................................46 3.10.3 earphone inte rface configuration ...........................................................................46 3.10.4 referenced electr onic charac teristic.......................................................................47 3.11 sim interface............................................................................................................. .......48 3.11.1 sim card application ..............................................................................................48 3.11.2 design considerations for sim card holder ............................................................49
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 4 3.12 lcd interface............................................................................................................. ......52 3.13 general purpose in put & output (gpio) ...........................................................................52 3.14 adc ....................................................................................................................... ..........52 3.15 behaviors of the ri line (serial port1 interface only).......................................................53 3.16 network status indication led lamp ...............................................................................54 3.17 buzzer .................................................................................................................... ..........55 4 gps application interface.................................................................................................... .........56 4.1 theory of operation........................................................................................................ ....56 4.2 technical data............................................................................................................. ........57 4.3 pin description............................................................................................................ ........58 4.4 turn on the gps part of SIM548 .......................................................................................60 4.5 the theory of th e gps rtc circuit ....................................................................................61 4.6 the theory of th e reset circuit .......................................................................................62 4.7 gps opera tion modes ........................................................................................................ .63 4.8 serial interface of the SIM548 gps part............................................................................63 4.9 start-up procedure ......................................................................................................... .....64 4.9.1 coldstart ................................................................................................................ ...64 4.9.2 warmstart ................................................................................................................ .64 4.9.3 hotstart ................................................................................................................. ....65 5 antenna interface ............................................................................................................ .............66 5.1 gsm antenna................................................................................................................ .....66 5.1.1 antenna connector....................................................................................................66 5.1.2 antenna pad.............................................................................................................. 66 5.1.3 module rf output power..........................................................................................68 5.1.4 module rf receive sensitivity..................................................................................68 5.1.5 module operating frequencies ..................................................................................68 5.2 gps antenna ................................................................................................................ ......68 5.2.1 gps antenna connection.........................................................................................68 5.2.2 gps antenna choice consideration ........................................................................69 6 electrical, reliability and radio characteristics ............................................................................ .72 6.1 absolute maximum ratings.................................................................................................72 6.2 operating temperatures ..................................................................................................... .72 6.3 power supp ly rating........................................................................................................ ....73 6.4 current consumption ........................................................................................................ ..74 6.4.1 the current consumption of the SIM548 gsm part.................................................74 6.4.2 the current consumption of the SIM548 gps part ..................................................75 6.5 electrostatic discharge.................................................................................................... ....78 7 mechanics .................................................................................................................... ................80 7.1 mechanical dimensions of SIM548....................................................................................80 7.2 mounting SIM548 onto th e application platform...............................................................81 7.3 board-to-board connector ..................................................................................................81 7.3.1 mechanical dimensions of 55201-087 8 ....................................................................81 7.3.2 adapte r cabling ........................................................................................................83 7.3.3 pin assignment of board-to-board connector of SIM548 ........................................84
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 5 appendix d ? tables and figures table index table 1: related documents ..................................................................................................... 8 table 2: terms an d abbreviat ions .........................................................................................9 table 3: SIM548 key features................................................................................................... .13 table 4: coding schemes and maximum net data rates over air interface ..15 table 5: board-to-board connector pin description ...............................................16 table 6: overview of operating modes..............................................................................19 table 7: at commands us ed in alarm mode .....................................................................25 table 8: spec of re commended battery pack .................................................................30 table 9: operating modes ....................................................................................................... ..32 table 10: at command usually used in ghost mode ...................................................33 table 11: summary of state transitions...........................................................................35 table 12: logic levels of serial ports pins.....................................................................40 table 13: audio interface signal..........................................................................................44 table 14: mic input characteristics ...................................................................................47 table 15: spk output characteristics ...............................................................................47 table 16: buzzer output characteristics .......................................................................47 table 17: signal of sim interface ( board-to-board connector).........................48 table 18: pin description (amp henol sim card holder) ............................................50 table 19: pin description (m olex sim card holder) ....................................................51 table 20: pin define of lcd interface .................................................................................52 table 21: gpio of the gsm part of SIM548 ............................................................................52 table 22: adc pin of the gsm part of SIM548......................................................................53 table 23: behaviours of the ri line......................................................................................53 table 24: working state of network status indication led pin ..........................54 table 25: pin description ...................................................................................................... .....58 table 26: consolidated pin characteristics..................................................................60 table 27: gps oper ation modes ...............................................................................................63 table 28: the gsm part of SIM548 conducted rf output power..............................68 table 29: the gsm part of SIM548 conducted rf conducted receive sensitivity .................................................................................................................... ...........68 table 30: the gsm part of sim5 48 operating frequencies..........................................68 table 31: absolute maximum ratings (gsm part)..........................................................72 table 32: absolute maximum ratings (gps part) ...........................................................72 table 33: SIM548 oper ating temperature...........................................................................72 table 34: power supply ra ting (gsm part).........................................................................73 table 35: power supply rating (gps part) ..........................................................................74 table 36: current consum ption (gsm part) .....................................................................74 table 37: the esd endure statue measured table (temperature: 25 , humidity: 45% ) ................................................................................................................ ........79 table 38: pin assignment of SIM548........................................................................................84
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 6 figure index figure 1: vbat input........................................................................................................... ...........21 figure 2: vbat voltage drop during transmit burst ................................................21 figure 3: timing of turn on system .....................................................................................23 figure 4: timing of turn off system ...................................................................................26 figure 5: timing of restart system .....................................................................................28 figure 6: battery c harger and pack ..................................................................................29 figure 7: rtc supply from non-chargeabl e battery .................................................37 figure 8: rtc supply from rechargeable battery ......................................................37 figure 9: rtc supply from capacitor ..................................................................................38 figure 10: panasonic eecemoe2 04a charge characteristic ...................................38 figure 11: maxell tc614 charge characteristic ..........................................................39 figure 12: seiko ts621 charge characteristic ...............................................................39 figure 13: interface of serial ports ...................................................................................41 figure 14: interface of so ftware upgrade&debug ....................................................43 figure 15: speaker inte rface configuration .................................................................45 figure 16: speaker interface with amplifier configuration ................................45 figure 17: microphone inter face configuration ........................................................46 figure 18: earphone inter face configuration..............................................................46 figure 19: sim interface referenc e circuit with 8pin sim card............................49 figure 20: sim interface referenc e circuit with 6pin sim card............................49 figure 21: amphenol c707-10m 006 512 2 sim card holder .............................................50 figure 22: molex 91228 sim card holder ............................................................................51 figure 23: the gsm part of si m548 services as receiver .............................................53 figure 24: the gsm part of SIM548 services as caller .................................................54 figure 25: reference circuit for network status led .............................................55 figure 26: reference circuit fo r buzzer..........................................................................55 figure 27: theory of operation..............................................................................................56 figure 28: turn on the gps module ......................................................................................61 figure 29: theory of the gps rtc circuit ..........................................................................62 figure 30: theory of the reset circuit ..............................................................................62 figure 31: rf connec tor and rf pad.....................................................................................67 figure 32: rf connector ........................................................................................................ ....69 figure 33: power down mode...................................................................................................76 figure 34: push-to-fix mode .................................................................................................... .77 figure 35: power consumpt ion in the ptf mode.............................................................78 figure 36: SIM548 top view and side view............................................................................80 figure 37: 55201-087 8 board-to-board connector .........................................................81 figure 38: board to board connector physical photo ............................................82 figure 39: mm9329- 2700b........................................................................................................ ........83 figure 40: rf co nnector mxtk................................................................................................83 figure 41: phys ical SIM548 ..................................................................................................... ....86 figure 42: reference circuit with external mcu (example application) .......87
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 7 version history date version description of change author 2007-02-07 1.01 origin liuyi
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 8 1 introduction this document describes the hardware interface of the simcom SIM548 module that connects to the specific application and the air interface. as SIM548 can be integrated with a wide range of applications, all functional components of SIM548 are described in great detail. this document can help you quickly understand SIM548 interface specifications, electrical and mechanical details. with the help of this document and other SIM548 application notes, user guide, you can use SIM548 module to design and set-up mobile applications quickly. 1.1 related documents table 1: related documents sn document name remark [1] sim508_atc sim508_atc [2] itu-t draft new recommendation v.25ter: serial asynchronous automatic dialing and control [3] gsm 07.07: digital cellular telecommunications (phase 2+); at command set for gsm mobile equipment (me) [4] gsm 07.05: digital cellular telecommunications (phase 2+); use of data terminal equipment ? data circuit terminating equipment (dte ? dce) interface for shor t message service (sms) and cell broadcast service (cbs) [5] gsm 07.10: support gsm 07.10 multiplexing protocol [6] gsm 11.14: digital cellular telecommunications system (phase 2+); specification of the sim applicat ion toolkit for the subscriber identity module ? mobile equipment (sim ? me) interface [7] gsm 11.11: digital cellular telecommunications system (phase 2+); specification of the subscriber identity module ? mobile equipment (sim ? me) interface [8] gsm 03.38: digital cellular telecommunications system (phase 2+);
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 9 alphabets and language-specific information [9] gsm 11.10 digital cellular telecommunications system (phase 2) mobile station (ms) conformance specification part 1: conformance specification 1.2 terms and abbreviations table 2: terms a nd abbreviations gsm part abbreviation description adc analog-to-digital converter arp antenna reference point asic application specific integrated circuit ber bit error rate bts base transceiver station chap challenge handshake authentication protocol cs coding scheme csd circuit switched data cts clear to send dac digital-to-analog converter drx discontinuous reception dsp digital signal processor dte data terminal equipment (typically computer, terminal, printer) dtr data terminal ready dtx discontinuous transmission efr enhanced full rate egsm enhanced gsm 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
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 10 gsm global standard for mobile communications hr half rate i/o input/output ic integrated circuit imei international mobile equipment identity kbps kilo bits per second led light emitting diode li-ion lithium-ion mo mobile originated ms mobile station (gsm engine), also referred to as te mt mobile terminated pap password authentication protocol pbcch packet switched broadcast control channel pcb printed circuit board pcs personal communication system, also referred to as gsm 1900 pdu protocol data unit ppp point-to-point protocol rf radio frequency rms root mean square (value) rp receive protocol rtc real time clock rx receive direction sa selective availability sar specific absorption rate sim subscriber identification module sms short message service tdma time division multiple access te terminal equipment, also referred to as dte tx transmit direction urc unsolicited result code ussd unstructured supplementary service data vswr voltage standing wave ratio vmax maximum voltage value vnorm normal voltage value vmin minimum voltage value vihmax maximum input high level voltage value vihmin minimum input high level voltage value vilmax maximum input low level voltage value
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 11 vilmin minimum input low level voltage value vimax absolute maximum input voltage value vimin absolute minimum input voltage value vohmax maximum output high level voltage value vohmin minimum output high level voltage value volmax maximum output low level voltage value volmin minimum output low level voltage value phonebook abbreviations fd sim fix dialing phonebook ld sim last dialing phonebook (list of numbers most recently dialed) mc mobile equipment list of unansw ered mt calls (missed calls) me mobile equipment phonebook rc mobile equipment list of received calls sm sim phonebook dc me dialed calls list(+cpbw may not be applicable or this storage)(same as ld) la last number all list (lnd/lnm/lnr) on sim (or me) own numbers (msisdns) list sd sim service dial number vm sim voice mailbox bn sim barred dialed number gps part abbreviation description atp adaptive trickle power mode. dgps differential gps gga gps fixed data gps global positioning system lna low noise amplifier rtcm radio technical commission for maritime services
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 12 2 product concept designed for global market, SIM548 is a quad-band gsm/gprs engine that works on frequencies gsm 850mhz, egsm 900 mhz, dcs 1800 mhz and pcs 1900 mhz and supports also gps technology for satellite navigation. SIM548 provides gprs multi-slot class10 / class 8 (option) capabilities and supports the gprs coding schemes cs-1, cs-2, cs-3 and cs-4. with a tiny configuration of 55mm x 34mm x 3.0 mm, SIM548 can fit almost all the space requirement in your application, such as smart phone, pda phone, gps hand-held device and other mobile device, or applications of avl (automated vehicle location), location service and so on. the physical interface to the mobile application is made through an 80-pin board-to-board connector, which provides all hardware interfaces between the module and customers? boards except the rf antenna interface. z the keypad and spi display interface will give you the flexibility to develop customized applications. z one serial gsm port and two serial gps pots can help you easily develop your applications. z two audio channels include two microphones inputs and two speaker outputs. these can be easily configured by at command. z charge interface with the charge circuit integrated inside the SIM548, it is very suitable for the battery power application. SIM548 provides gsm rf antenna interface with two alternatives: antenna connector and antenna pad. the antenna connector is murata mm9329-2700. and customer?s antenna can be soldered to the antenna pad. a separate gps antenna must be connected to the gps part of the module in order to properly receive satellite data. the SIM548 is designed with power saving technique, the current consumption of gsm part maintains is as low as about 3ma in sleep mode. the SIM548 is integrated with the tcp/ip protocol, extended tcp/ip at commands are developed for customers to use the tcp/ip protocol easily, which is very useful for those data transfer applications.
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 13 2.1 SIM548 key features at a glance table 3: SIM548 key features feature implementation power supply z gsm part: supply voltage 3.4v ? 4.5v z gps part: separate power supply source: 3.3v 5% power saving z gsm part: typical power cons umption in sleep mode to 3.5ma ( bs-pa-mfrms=5 ) z gps part: power down mode / push-to-fix mode charging supports charging control for li-ion battery frequency bands z SIM548 quad-band: gsm850, egsm 900, dcs 1800, pcs 1900. the SIM548 can search the 4 frequency bands automatically. the frequency bands also can be set by at command.. z compliant to gsm phase 2/2+ gsm class small ms transmit power z class 4 (2w) at gsm 850 and egsm 900 z class 1 (1w) at dcs 1800 and pcs 1900 gprs connectivity z gprs multi-slot class 10 (default) z gprs multi-slot class 8 (option) z gprs mobile station class b gps features z gps receiver with sirfstar iii gsc3f chip set z processor type arm7/tdmi z software version: sirf gsw3 temperature range z normal operation: -20c to +55c z restricted operation: -30c to -20c and +55c to +80c z storage temperature -40c to +85c data gprs: z gprs data downlink transfer: max. 85.6 kbps z gprs data uplink transfer: max. 42.8 kbps z coding scheme: cs-1, cs-2, cs-3 and cs-4 z SIM548 supports the protocols pap (password authentication protocol) usually used for ppp connections. z the SIM548 integrates the tcp/ip protocol.
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 14 csd: z support packet switched broa dcast control channel (pbcch) z csd transmission rates: 2.4, 4.8, 9.6, 14.4 kbps, non-transparent z unstructured supplementary services data (ussd) support sms z mt, mo, cb, text and pdu mode z sms storage: sim card fax group 3 class 1 sim interface support sim card: 1.8v ,3v external antenna z gsm part: connected via 50 ohm antenna connector or antenna pad z gps part: separate gps antenna co nnector. see figure 33 for details audio features speech codec modes: z half rate (ets 06.20) z full rate (ets 06.10) z enhanced full rate (ets 06.50 / 06.60 / 06.80) z echo suppression serial gsm interfaces and debug interfaces z serial port: seven lines on serial port interface z serial port can be used for csd fax, gprs service and send at command of controlling module. z serial port can use multiplexing function z autobauding supports baud rate from 1200 bps to 115200bps. z debug port: two lines on debug port interface dbg_txd and dbg_rxd z debug port only used for debugging two serial gps interfaces z serial port a: two lines on serial port a, gps_txa and gps_rxa z serial port b: two lines on serial port b, gps_txb and gps_rxb phonebook management support phonebook types: sm, fd, ld, mc, rc, on, me,bn,vm,la,dc,sd sim application toolkit support sat class 3, gsm 11.14 release 99 real time clock implemented timer function programmable via at command
SIM548 hardware design physical characteristics size: 550.15 x 340.15 x 3.30.3 mm (including application connector) 550.15 x 340.15 x 2.90.3 mm (excluding application connector) weight: 11g firmware upgrade firmware upgrade ove r serial interface table 4: coding scheme s and maximum net data rates over air interface coding scheme 1 timeslot 2 timeslot 4 timeslot cs-1: 9.05kbps 18.1kbps 36.2kbps cs-2: 13.4kbps 26.8kbps 53.6kbps cs-3: 15.6kbps 31.2kbps 62.4kbps cs-4: 21.4kbps 42.8kbps 85.6kbps SIM548_hd_v1.01 07.02.2007 15
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 16 3 gsm application interface all hardware interfaces except rf interface th at connects SIM548 to the customers? cellular application platform is through an 80-pin 0.5mm pitch board-to-board connector. sub-interfaces included in this board-to-board connector are described in detail in following chapters: z power supply and charging control ( see chapters 3.3 and 3.5 ) z gsm serial interface ( see chapter 3.9 ) z two analog audio interfaces ( see chapter 3.10 ) z sim interface ( see chapter 3.11 ) electrical and mechanical characteristics of the board-to-board connector are specified in chapter 6. there we also ordering information for mating connectors. 3.1 pin description table 5: board-to-board co nnector pin description power supply pin name i/o description dc characteristics vbat 5 vbat pins of the board-to-board connector are dedicated to connect the supply voltage. the power supply of the gsm part of SIM548 has to be a single voltage source of vbat= 3.4v...4.5v. it must be able to provide sufficient current in a transmit burst which typically rises to 2a.mostly, these 5 pins are voltage input vmax= 4.5v vmin=3.4v vnorm=4.0v vrtc i/o rtc current input from the backup battery when the vbat is not supplied for the system. current output to backup battery when the main battery is present and the backup battery is low voltage state. vmax=2.0v vmin=1.2v vnorm=1.8v inorm= 20ua vchg i voltage input for the charge circuit; making the system detect the charger. vmax=5.25v vmin=1.1 * vbat vnorm=5.1v gnd digital ground
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 17 power on or power off pin name i/o description dc characteristics pwrkey i voltage input for power on key. pwrkey get a low level voltage for user to power on or power off the system. the user should keep pressing the key for a moment when power on or power off the system. because the system need margin time assert the software. vilmax=0.2*vbat vihmin=0.6*vbat vimax=vbat audio interface pin name i/o description dc characteristics mic1p mic1n i positive and negative voice-band input audio dc characteristics refer to chapter 3.9.4 mic2p mic2n i auxiliary positive and negative voice-band input spk1p spk1n o positive and negative voice-band output spk2p spk2n o auxiliary positive and negative voice-band output buzzer o buzzer output agnd analog ground display interface disp_data i/o disp_clk o disp_d/c o disp_cs o disp_rst o display interface vilmin=0v vilmax=0.9 vihmin=2.0 vihmax= 3.2 volmin=gnd volmax=0.2v vohmin=2.7 vohmax=2.9 keypad interface kbc0~kbc4 o kbr0~kbr4 i keypad array vilmin=0v vilmax=0.9 vihmin=2.0 vihmax= 3.2 volmin=gnd volmax=0.2v vohmin=2.7 vohmax=2.9 gerneral purpose input/output pin name i/o description dc characteristics
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 18 netlight o network indicate light status o another indication for system on/off gpio0 i/o general purpose input/output port gpio1 i/o general purpose input/output port vilmin=0v vilmax=0.9 vihmin=2.0 vihmax= 3.2 volmin=gnd volmax=0.2v vohmin=2.7 vohmax=2.9 serial interface pin name i/o description dc characteristics dtr i data terminal ready rxd i receive data txd o transmit data rts i request to send cts o clear to send ri o ring indicator dcd o data carrier detection debug interface dbg_txd o dbg_rxd i serial interface for debugging and communication by at command vilmin=0v vilmax=0.9 vihmin=2.0 vihmax= 3.2 volmin=gnd volmax=0.2v vohmin=2.7 vohmax=2.9 sim interface pin name i/o description dc characteristics sim_vdd o voltage supply for sim card the voltage can be select by software either 1.8v or 2.85v sim_data i/o sim data output sim_clk o sim clock sim_presence i sim card detection sim_rst o sim reset vilmin=0v vilmax=0.3* vsim vihmin=0.7* vsim vihmax= vsim +0.3 volmin=gnd volmax=0.2v vohmin= vsim -0.2 vohmax= vsim auxadc pin name i/o description dc characteristics adc0 i general purpose analog to digital converter. input voltage value: 0v to 2.4v temp_bat i for measure the battery temperature
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 19 3.2 operating modes the table below briefly summarizes the various operating modes referred to in the following chapters. table 6: overview of operating modes mode function normal operation gsm/gprs sleep module will automati cally go into sleep mode if dtr is set to high level and there is no on air hardware interrupt (such as gpio interrupt or data on serial port). in this case, the current consumption of module will reduce to the minimal level. during sleep mode, the module can still receive paging message and sms from the system normally. gsm idle software is active. module has registered to the gsm network, and the module is ready to send and receive. gsm talk connection is going on between two subscribers. in this case, the power consumption depends on network settings such as dtx off/on, fr/efr/hr, hopping sequences, antenna. gprs standby module is ready for gprs data transfer, but no data is currently sent or received. in this case, power consumption depends on network settings and gprs configuration. gprs data there is gprs data in transfer (ppp or tcp or udp). in this case, power consumption is related with network settings (e.g. power control level), uplink / downlink data rates and gprs configuration (e.g. used multi-slot settings). power down normal shutdown by sending the ?at+cpowd? command or using the pwrkey. the power management asic disconnects the power supply from the base band part of the module, only the power supply for the rtc is remained. software is not active. the serial interfaces are not accessible. operating voltage (connected to vbat) remains applied. minimum functionality mode (without use the ?at+cfun? command can set the module to a minimum functionality mode without remove the power supply. in this case, the rf part of the module will not work and the sim card will not be accessible. although rf part and
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 20 remove power supply) sim card will be closed all, the serial interface is still accessible. the power consumption in this case is very low. alarm mode rtc alert function launches this restricted operation while the module is in power down mode. SIM548 will not be registered to gsm network and only parts of at commands can be available. ghost mode (charge-only mode) ghost mode means off and charging mode . in this mode, the module can not be registered to gsm network and only limited at commands can be accessible, the following wa y will launch ghost mode: z from power down mode: connect charger to the module?s vchg pin, and battery is present while SIM548 is power down. z from normal mode: connect charger to the module?s vchg pin, and battery is present, then power down the module by ?at+cpowd 1? charge mode during normal operation start charging while the module is in normal mode (including: sleep, idle, talk, gprs idle and gprs data) 3.3 power supply the power supply of SIM548 gsm part is from a single voltage source of vbat= 3.4v...4.5v. in some case, the ripple in a transmit burst may cause voltage drops when current consumption rise to typical peaks of 2a.so the power supply must be able to provide sufficient current up to 2a. for the vbat input, a local bypass capacitor is recommended. a capacitor (about 100f, low esr) is recommended. multi-layer ceramic ch ip (mlcc) capacitors can provide the best combination of low esr and small size but may not be cost effective. a lower cost choice may be a 100 f tantalum capacitor (low esr) with a small (0.1 f to 1f) ceramic in parallel, which is illustrated as figure1. and the capacitors should put as closer as possible to the SIM548 vbat pins.
SIM548 hardware design figure 1: vbat input the following figure is the vbat voltage ripple wave at the maximum power transmit phase, the test condition is vbat=4.0v, vbat maximum output current =2a, c a =100 f tantalum capacitor (esr=0.7 ? ) and c b =1f. figure 2: vbat voltage drop during transmit burst 3.3.1 power supply pins on th e board-to-board connector five vbat pins of the board-to-board connector are dedicated to connect the supply voltage. the vchg pin serves as control signal for charging a li-ion battery. vrtc pin can be used to back up the rtc. 3.3.2 minimizing power losses please pay special attention to the supply power when you are designing y our applications. please make sure that the input voltage will never drop below 3.4v even in a transmit burst during which the current consumption may rise up to 2a. if the power voltage drops below 3.4v, the module may be switched off. so the impedance from extern power supply to module vbat pins should be as low as possible. when using a battery, you should also take the impedance of the battery SIM548_hd_v1.01 07.02.2007 21
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 22 pack, the battery connector and pcb track on the host board into account. 3.3.3 monitoring power supply to monitor the supply voltage, you can use the ?at+cbc? command which include three parameters: charge state, voltage percent and voltage value (in mv). it returns charge state the battery voltage 1-100 percent of capacity an d actual value measured at vbat and gnd. the voltage is continuously measured at intervals depending on the operating mode. the displayed voltage (in mv) is averaged over th e last measuring period before the at+cbc command was executed. for details plea se refer to document [1] 3.4 power up and down scenarios 3.4.1 turn on the gsm part of SIM548 the gsm part of SIM548 can be turned on by various ways, which are described in following chapters: z via pwrkey pin: starts normal operating mode ( see chapter 3.4.1.1 ); z via vchg pin: starts ghost modes ( see chapter 3.4.1.2 ); z via rtc interrupt: starts alarm modes ( see chapter 3.4.1.3) note: only enter at command through serial po rt after SIM548 is power on and unsolicited result code ?rdy? is received from serial port. note: if configured to a fix baud rate, SIM548 wi ll send the result code ?rdy? to indicate that it is ready to operate. this result code does no t appear when autobauding is active. you can use at+ipr=x;&w to set a fix baud rate and save the configuration to non-volatile flash memory. see chapter at+ipr in document [1]. 3.4.1.1 turn on the gsm part of sim5 48 using the pwrkey pin (power on) you can turn on the gsm part of SIM548 by driving the pwrkey to a low level voltage for period time. the power on scenarios illustrate as the following figure.
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 23 figure 3: timing of turn on system when power on procedure complete, the gsm part of SIM548 will send out following result code to indicate the module is ready to operate and status pin will drive to 2.8v and keep this level when in work mode. only set baud rate that serial port can send out ?rdy?, if set auto-baud rate, serial port will send nothing. rdy 3.4.1.2 turn on the gsm part of SIM548 using the vchg signal as described in chapter 3.5, charger can be connected to the gsm part of SIM548?s vchg pin regardless of the module?s operating mode. if the charger is connected to the module?s vchg pin while the gsm part of SIM548 is in power down mode, it will go into the ghost m ode (off and charging). in this mode, the module will not register to network, and only a few at commands can work in this mode. for detailed information please refers to chapter 3.5.4. when module is powered on using the vchg signal, the gsm part of SIM548 sends out result code as following when fixed baud rate: rdy ghost mode
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 24 +cfun: 0 in ghost mode, by driving the pwrkey to a low level voltage for period time (please refer to the power on scenarios in 3.4.1.1), the gsm part of SIM548 will power up and go into charge mode (charging in normal mode), all operation an d at commands can be available. in this case, the gsm part of SIM548 will send out result code as following: from ghost mode to normal mode 3.4.1.3 turn on the gsm part of SIM548 using the rtc (alarm mode) alarm mode is a power-on approach by using th e rtc. the alert function of rtc makes the gsm part of SIM548 wake up while the module is power off. in alarm mode, the gsm part of SIM548 will not register to gsm network and the software protocol stack is close. thus the parts of at commands related with sim card and protocol stack will not accessible, and the others can be used as well as in normal mode. use the at+calarm command to set the alarm tim e. the rtc remains the alarm time if the gsm part of SIM548 was power down by ?at+cpowd=1? or by pwrkey pin. once the alarm time is expired and executed, the gsm part of sim5 48 goes into the alarm mode. in this case, the gsm part of SIM548 will send out an unsolicited result code (urc): rdy alarm mode during alarm mode, use at+cfun command to query the status of software protocol stack; it will return 0 which indicates that the protocol stack is closed. then after 90s, the gsm part of SIM548 will power down automatically. however, during alarm mode, if the software protocol is started by at+cfun=1 command, the process of automatic power down will not be available. in alarm mode, driving the pwrkey to a low level voltage for a period will cause the gsm part of SIM548 to power down (please re fer to the power down scenario ). the table follow briefly summarizes the at comm ands that are used usually during alarm mode, for details of the in structions refer to document [1] :
SIM548 hardware design table 7: at commands used in alarm mode at command use at+calarm set alarm time at+cclk set data and time of rtc at + c p o w d power down at+cfun start or close the protocol stack 3.4.2 turn off the gsm part of SIM548 following procedure can be used to turn off the gsm part of SIM548: z normal power down procedure: turn off the gsm part of SIM548 using the pwrkey pin ( see chapter 3.4.2.1 ) z normal power down procedure: turn off the gsm part of SIM548 using at command ( see chapter 3.4.2.2 ) z under-voltage automatic shutdown: take effect if under voltage is detected ( see chapter 3.4.2.3 ) z over-temperature automatic shutdown: take effect if under voltage is detected ( see chapter 3.4.2.4 ) 3.4.2.1 turn off the gsm part of SIM548 using the pwrkey pin (power down) you can turn off the gsm part of SIM548 by driving the pwrkey to a low level voltage for period time. the power down scenarios illustrate as figure 4. this procedure will let the module to log off from the network and allow the software to enter into a secure state and save data before co mpletely disconnect the power supply. before the completion of the switching off procedure the module will send out result code: normal power down after this moment, the at commands can?t be executed. the module enters the power down mode, only the rtc is still active. power down can also be indicated by status pin, which is a low level voltage in this mode. SIM548_hd_v1.01 07.02.2007 25
SIM548 hardware design figure 4: timing of turn off system 3.4.2.2 turn off the gsm part of SIM548 using at command you can use an at command ?at+cpowd=1? to turn off the module. this command will let the module to log off from the network and allow the software to enter into a secure state and save data before completely disconnect the power supply. before switching off, the module will send out result code: normal power down after this moment, the commands can?t be executed. the module enters the power down mode, only the rtc is still active. power down can also be indicated by status pin, which is a low level voltage in this mode. please refer to document [1] for detail about the at command of ?at+cpowd?. 3.4.2.3 under-voltage automatic shutdown software will constantly monitor the voltage applied on the vbat, if the measured battery voltage is no more than 3.5v, the module will send out result code: power low warnning SIM548_hd_v1.01 07.02.2007 26
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 27 if the measured battery voltage is no more than 3.4v, the following urc will be presented: power low down after this moment, no further more at commands can be executed. the module will log off from network and enters power down mode, only the rtc is still active. power down can also be indicated by status pin, which is a low level voltage in this mode. 3.4.2.4 over-temperature automatic shutdown software will constantly monitor the temperature of the module, if the measured temperature is equal or higher than 80 , the following urc will be presented: +cmte: 1 if the measured temperature ? -30 , the following urc will be presented: +cmte:-1 the uncritical temperature range is -35 to 85 . if the measured temperature ? 85 or ? -35, the module will be automatic shutdown soon. if the measured temperature ? 85 , the following urc will be presented: +cmte:2 if the measured temperature ? -35 , the following urc will be presented: +cmte:-2 after this moment, the at commands can?t be executed. the module will log off from network and enter power down mode, only the rtc is still active. power down can also be indicated by status pin, which is a low level voltage in this mode. to monitor the temperature, you can use the ?at+cmte? command to measure the temperature when the module is power on. for details plea se refer to document [1]
SIM548 hardware design 3.4.3 restart the gsm part of SIM548 using the pwrkey pin you can restart SIM548 by driving the pwrkey to a low level voltage for period time, same as turn on SIM548 using the pwrkey pin. before restart the SIM548, you need delay at least 500ms from detecting the status low level on. the restart scenarios illustrate as the following figure. figure 5: timing of restart system 3.5 charging interface the gsm part of SIM548 has integrated a charging circuit inside the module for li-ion batteries charging control, which make it very convenient for applications to manage their battery charging. a common connection is shown in the following figure: SIM548_hd_v1.01 07.02.2007 28
SIM548 hardware design module figure 6: battery charger and pack the temp_bat function should be supported by the software in the module. it?s a customization function. the r temp is a ntc thermistor. we recomme nd to use ncp15xh103f03rc from murata. the impedance of the ntc thermistor is 10kohm in 25 . please refer to the above figure for the reference circuit. 3.5.1 battery pack characteristics the gsm part of SIM548 has optimized the charging algorithm for the li-ion battery that meets the characteristics listed below. to use the gsm pa rt of SIM548?s charging algorithm properly, it is recommended that the battery pack you integrated into your application is compliant with these specifications. the battery pack compliant with th ese specifications is also important for the at command ?at+cbc? to monitor the voltage of battery, or the ?at+cbc? may return incorrect battery capacity values. z the maximum charging voltage of the li-ion battery pack is 4.2v and the capacity is 580mah. battery packs with a capacity down to 580mah or more than 580mah are allowed, too. z the pack should have a protection circuit to avoid overcharging, deep discharging and over-current. this circuit should be insensitive to pulsed current. z on the gsm part of SIM548, the build-in circuit of the gsm part of SIM548?s power management chipset monitors the supply voltage constantly. once the under-voltage is SIM548_hd_v1.01 07.02.2007 29
SIM548 hardware design detected, the gsm part of SIM548 will power down automatically. under-voltage thresholds are specific to the battery pack. z the internal resistance of the battery and the protection circuit should be as low as possible. it is recommended not to exceed 200m . z the battery pack must be protected from reverse pole connection. 3.5.2 recommended battery pack following is the spec of recommended battery pack: table 8: spec of recommended battery pack product name & type byd, li-ion, 3.7v, 580mah to obtain more information please contact : byd company limited normal voltage 3.7v capacity minimum 580mah charge voltage 4.2000.049v max charge current 1.5c charge method cc / cv (constant current / constant voltage) max discharge current 1.5c (for continuous discharging mode) discharge cut-off voltage 2.75v/ cell internal resistance initial ? 200m after 400cycles ? 270m 3.5.3 implemented charging technique the gsm part of SIM548 includes the function for battery charging. there are three pins in the connector related with the battery charging function: vchg, vbat and bat_temp pins. the vchg pin is driven by an external voltage, system can use this pin to detect a charger supply and provide most charging current through the gsm part of SIM548 module to battery when charging is in fast charge state. the vbat give out charging current from the gsm part of SIM548 module to external battery. bat_temp pin is for user to measure the battery temperature. just let this pin open if battery temperature measuring is not your concern. SIM548_hd_v1.01 07.02.2007 30
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 31 so it is very simple to implement charging technique, you need only connect the charger to the vchg pin and connect the battery to the vbat pin. the gsm part of SIM548 detect charger supply and the battery is present, battery charging will happen. if there is no charger supply or no ba ttery present, the charging will not be enabled. normally, there are three main states in whole charging procedure. z ddlo charge and uvlo charge; z fast charge; z trickle charge; ddlo charge and uvlo charge: ddlo (deep discharge lock out) is the state of battery when its voltage under 2.4v. and uvlo (under voltage lock out) means the battery voltage less than 3.2v and more than 2.4v. the battery is not suitable for fast charge when its condition is ddlo or uvlo. the gsm part of SIM548 provides a small constant current to the battery when the battery is between ddlo and uvlo. in ddlo charge, the gsm part of SIM548 gives out 5ma current to the battery. and in uvlo charge, the gsm part of SIM548 provide about 25ma current to the battery. ddlo charge terminated when the battery voltage reaches 2.4v. uvlo charge terminated when the battery voltage is up to 3.2v. both ddlo an d uvlo charge are controlled by the gsm part of SIM548 hardware only. fast charge: if there is a charger supply a nd battery present and the battery is not in ddlo and uvlo, the gsm part of SIM548 will enter fast charge state. fast charge controlled by the software. fast charge delivers a strong and constant current (about 450ma) through vbat pin to the battery until battery voltage reach 4.2v. trickle charge: after fast charging, the battery voltage near the whole battery capacity, trick charge begins .in this state, the gsm part of SIM548 charge the battery under constant voltage. 3.5.4 operating modes during charging the battery can be charged during various operating mode. that means that when the gsm engine
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 32 is in normal mode (sleep, idle, talk, gprs idle or gprs data mode), charging can be in progress while the gsm part of SIM548 remains operational (in this case the voltage supply should be sufficient). here we name charging in normal mode as charge mode. if the charger is connected to the module?s vchg pin and the battery is connected to the vbat pin while the gsm part of SIM548 is in power down mode, the gsm part of SIM548 will go into the ghost mode (off and charging). the following table gives the difference between charge mode and ghost mode. table 9: operating modes how to activate mode features charge mode connect charger to module?s vchg pin and connect battery to vbat pin of module while the gsm part of SIM548 is in normal operating mode, including: idle, talk mode; sleep mode etc; z gsm remains operational and registered gsm network while charging is in progress; z the serial interfaces are available in idle, talk mode, the at command set can be used fully in this case; in sleep mode, the serial interfaces are not available, once the serial port is connected and there is data in transfer. then the gsm part of SIM548 will exit the sleep mode. ghost mode connect charger to module?s vchg pin while the gsm part of SIM548 is in power down mode. important: in ghost mode not all the software task s are running. z battery can be charged when gsm engine is not registered to gsm network; z only a few at commands is available as listed below. note: vbat can not provide much more than 5ma cu rrent while SIM548 module is during the ddlo charge state. in other words it is stro ngly recommended that vbat should not be the main power supply in the application subsystem while SIM548 module is during the ddlo charge state.
SIM548 hardware design table 10: at command usua lly used in ghost mode at command function at+calarm set alarm time at+cclk set data and time of rtc at + c p o w d power down at+cbc indicated charge state and voltage at+cfun start or close the protocol set at command ? at+cfun =1 ?,module can be transferred from ghost mode to charging in normal mode, in ghost mode , the default value is 3.5.5 charger requirements following is the requirements of charger for the gsm part of SIM548. - simple transformer power plug - output voltage: 5.0v-5.25v - charging current limitation: 650ma - a 10v peak voltage is allowed for maximum 1ms when charging current is switched off. - a 1.6a peak current is allowed for maximum 1ms when charging current is switched on. 3.6 power saving there are two methods for the module to enter into low current consumption status. ?at+cfun? is used to set module into minimum functionality mode and dtr hardware interface signal can be used to set system to be sleep mode (or slow clocking mode). 3.6.1 minimum functionality mode minimum functionality mode reduces the functionality of the module to a minimum and, thus, minimizes the current consumption to the lowest level. this mode is set with the ?at+cfun? command which provides the choice of the functionality levels =0 1 4 SIM548_hd_v1.01 07.02.2007 33
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 34 z 0: minimum functionality; z 1: full functionality (default); z 4: disable phone both transmit and receive rf circuits; if the gsm part of SIM548 has been set to minimum functionality by ?at+cfun=0?, then the rf function and sim card function will be closed, in this case, the serial port is still accessible, but all at commands need rf function or sim card function will not be accessible. if the gsm part of SIM548 has been set by ?at+cfun=4?, the rf function will be closed, the serial port is still active in this case but all at commands need rf function will not accessible. after the gsm part of SIM548 has been set by ?at+cfun=0? or ?at+cfun=4?, it can return to full functionality by ?at+cfun=1?. for detailed information about ?at+cfun?, please refer to document [1] . 3.6.2 sleep mode (slow clock mode) we can control the gsm part of SIM548 module to enter or exit the sleep mode in customer applications through dtr signal. when dtr is in high level, at the same time there is no on air or audio activity is required and no hardware interrupt (such as gpio interrupt or data on serial port), the gsm part of SIM548 will enter sleep mode automatically. in this mode, the gsm part of SIM548 can still receive paging or sms from network. in sleep mode, the serial port is not accessible. note: for some special software versions, it requests to set at command ?at+csclk=1? to enable the sleep mode; the default value is 0, th at can?t make the module enter sleep mode, for more details please refer to the at command list. 3.6.3 wake up the gsm part of SIM548 from sleep mode when the gsm part of SIM548 is sleep mode, the following method can wake up the module z enable dtr pin to wake up the gsm part of SIM548
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 35 if dtr pin is pull down to a low level this signal will wake up the gsm part of SIM548 from power saving mode. the serial port will be active after dtr change to low level about 3ms. z receive a voice or data call from network to wake up the gsm part of SIM548 z receive a sms from network to wake up the gsm part of SIM548 z rtc alarm expired to wake up the gsm part of SIM548 3.7 summary of state transitions (except sleep mode) table 11: summary of state transitions further mode current mode power down normal mode ghost mode (charge-only mode) charging in normal alarm mode power down use pwrkey connect charger to vchg and connect battery to vbat no direct transition, but via ?ghost mode? or ?normal mode? switch on from power down mode by rtc normal mode at+cpowd or use pwrkey pin connect charger to vchg and connect battery to vbat, then switch off module by at+cpowd or using pwrkey connect charger to vchg pin of module and connect battery to vbat pin of module set alarm by ?at+cal arm?, and then switch off the module. when the timer expire, the module turn on and enter alarm mode
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 36 ghost mode (charge-only mode) disconnect charger no direct transition, but via ?charging in normal? mode turn on the module using pwrkey or set at command ?at+cfun=1? set alarm by ?at+cal arm?, when the timer expire, module will enter alarm mode charging in normal at+cpowd ?ghost mode?, then disconnect charger disconnect the charger switch off module by at+cpowd or using pwrkey no direct transition alarm mode use pwrkey pin or wait module switch off automatically use at+cfun no transition use at+cfun let module enter normal mode, then connect the charger to vchg pin of module 3.8 rtc backup the rtc (real time clock) power supply of modul e can be provided by an external battery or a battery (rechargeable or non-chargeable) through pin 14 on the board-to-board connector. there is a 10k resistance has been integrated in the gsm part of SIM548 modu le used for restricting current. you need only a coin-cell battery or a su per-cap to pin 14 to backup power supply for rtc. note: the vrtc couldn?t be designed to a nc pin in your circuit. you should connect the vrtc pin to a battery or a capacitor. the following figures show various sample circuits for rtc backup.
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 37 figure 7: rtc supply from non-chargeable battery figure 8: rtc supply from rechargeable battery
SIM548 hardware design figure 9: rtc supply from capacitor z li-battery backup rechargeable lithium coin cells such as the tc614 from maxell, or the ts621 from seiko, are also small in size, but have higher capacity than the double layer capacitors resulting in longer backup times. typical charge curves for each cell type are shown in following figures. note that the rechargeable lithium type coin cells generally come pre-charged from the vendor. figure 10: panasonic eecemoe204a charge characteristic SIM548_hd_v1.01 07.02.2007 38
SIM548 hardware design figure 11: maxell tc614 charge characteristic figure 12: seiko ts621 charge characteristic note: gold-capacitance backup some suitable coin cells are the electric double layer capacitors available from seiko (xc621), SIM548_hd_v1.01 07.02.2007 39
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 40 or from panasonic (eecem0e204a). they have a small physical size (6.8mm diameter) and a nominal capacity of 0.2f to 0.3f, giving hours of backup time. 3.9 gsm serial interface the gsm part of SIM548 provides two unbalanced asynchronous serial ports. one is the serial port and another is the debug port. the gsm part is designed as a dce (data communication equipment), following the traditional dce-dte (data terminal equipment) connection, the module and the client (dte) are connected through the following signal (as figure 13 shows). serial port z port/txd @ client sends data to the rxd signal line of module z port/rxd @ client receives data from the txd signal line of module debug port z port/txd @ client sends data to the dbg_rxd signal line of module z port/rxd @ client receives data from the dbg_txd signal line of module all pins of all serial ports have 8ma driver, the logic levels are described in following table table 12: logic levels of serial ports pins parameter min max unit logic low input 0 0.9 v logic high input 0.9 3.3 v logic low output gnd 0.2 v logic high output 2.8 3 v
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 41 figure 13: interface of serial ports 3.9.1 function of serial port & debug port supporting serial port z seven lines on serial port interface z contains data lines txd and rxd, state lines rts and cts, control lines dtr, dcd and ri; z serial port can be used for csd fax, gprs service and send at command of controlling module. serial port can use multiplexing function; z serial port supports the communication rate as following: 300, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200 default as 115200bps. z autobauding supports the communication rate as following: 1200, 2400, 4800, 9600, 19200, 38400, 57600, and 115200bps. autobauding allows the gsm engine to automatically detect the bitrate configured in the host application. the serial interf ace of the gsm engine supports autobauding for the following bitrates: 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200. factory setting is autobauding
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 42 enabled. this gives you the flexibility to put the gsm engine into operation no matter what bitrate your host application is configured to. to take advantage of autobaud mode specific attention must be paid to the following requirements: synchronization between dte and dce when dce powers on with the autobauding enabled, it is recommended to wait 2 to 3 seconds before sending the first at character. after receiving the ?ok? response, dte and dce are correctly synchronized. restrictions on au tobauding operation z the serial interface has to be operated at 8 data bits, no parity and 1 stop bit (factory setting). z the unsolicited result codes like "rdy" , "+cfun: 1" and "+cpin: ready? are not indicated when you start up the me while autobauding is enabled. this is due to the fact that the new baud rate is not detected unless dte and dce are correctly synchronized as described above. note: you can use at+ipr=x;&w to set a fixed baud rate and save the configuration to non-volatile flash memory. after the configuratio n was saved as fix baud rate, the unsolicited result codes like "rdy" should be received from the serial port all the time when the SIM548 was power on. debug port z two lines on serial port interface z only contains data lines /txd and /rxd z debug port only used for debugging. it cannot be used for csd call, fax call. and the debug port can not use multiplexing function; z debug port supports the communication rate as following: 9600, 19200, 38400, 57600, 115200bps 3.9.2 software upgrade and software debug the txd ? rxd ? dbg_txd ? dbg_rxd ? gnd must be connected to the io connector when user need to upgrade software and debug software, the txd ? rxd should be used for software upgrade and the dbg_txd ? dbg_rxd for software debug. the pwrkey pin is recommended to connect to the io connector. the user al so can add a switch between the pwrkey and the gnd. the pwrkey should be connected to the gnd when SIM548 is upgrading software. please refer to the following figures.
SIM548 hardware design note: the rts pin must be connected to the gnd in the customer circuit when only the txd and rxd used in the seri al port communication. figure 14: interface of software upgrade&debug note: the serial port doesn?t support the rs_232, it only supports the ttl level. you should add the level converter ic between the dce and dte, if you connect it to the pc. SIM548_hd_v1.01 07.02.2007 43
SIM548 hardware design 3.10 audio interfaces table 13: audio interface signal name pin function mic1p 54 microphone1 input + mic1n 56 microphone1 input - spk1p 53 audio1 output+ (ain1/aout1) spk1n 55 audio1 output- mic2p 58 microphone2 input + mic2n 60 microphone2 input - spk2p 57 audio2 output+ (ain2/aout2) spk2n 59 audio2 output- the module provides two analogy input channels, ain1 and ain2, which may be used for both microphone and line inputs. the electret microphone is recommended when the interface used for microphone. one of the two channels is typically used with a microphone built into a handset. the other channel is typically used with an external microphone or external line input. the module analogy input configuration is determined by control register settings and established using analogy multiplexers. for each channels, you can use at+cmic to set the input gain level of microphone, use at+echo to set the parameters for echo cancellation. also, you can use at+sidet to set the side-tone level. for de tail, please refer to document [1] .. it is suggested that you adopt the one of following two matching circuits in order to reject common mode noise and audio noise. the difference audio signals have to be layout according to difference signal layout rules. note: as show in figure 15 SIM548_hd_v1.01 07.02.2007 44
SIM548 hardware design 3.10.1 speaker interface configuration figure 15: speaker interface configuration figure 16: speaker interface wi th amplifier configuration SIM548_hd_v1.01 07.02.2007 45
SIM548 hardware design 3.10.2 microphone int erfaces configuration figure 17: microphone interface configuration 3.10.3 earphone interface configuration figure 18: earphone interface configuration SIM548_hd_v1.01 07.02.2007 46
SIM548 hardware design 3.10.4 referenced electronic characteristic table 14: mic input characteristics SIM548_hd_v1.01 07.02.2007 47 table 15: spk output characteristics parameter min typ max unit load resistance 27 32 ohm single ended ref level 0.5477 -12.04 vpp dbm load resistance 27 32 ohm normal output(spk1) differential ref level 1.0954 -6.02 vpp dbm load resistance 27 32 ohm single ended ref level 0.5477 -12.04 vpp dbm load resistance 27 32 ohm auxiliary output(spk2) differential ref level 1.0954 -6.02 vpp dbm table 16: buzzer output characteristics parameter min typ max unit working voltage 2.4 2.8 3.3 v working current 2 ma load resistance 1 k ohms parameter min typ max unit working voltage 1.2 1.5 2.0 v working current 200 500 ua external microphone load resistance 1.2 2.2 k ohms
SIM548 hardware design 3.11 sim interface 3.11.1 sim card application you can use at command to get information in sim card. for more information, please refer to document [1] . the sim interface supports the functionality of the gsm phase 1 specification and also supports the functionality of the new gsm phase 2+ specification for fast 64 kbps sim (intended for use with a sim application tool-kit). both 1.8v and 3.0v sim cards are supported. the sim interface is powered from an internal regulator in the module having normal voltage 3v. all pins reset as outputs driving low. logic levels are as described in table17 table 17: signal of sim int erface (board-to-board connector) pin signal description 25 sim_vdd sim card power supply, it can identify automatically the sim card power mode one is 3.0v10%, another is 1.8v10%. current is about 10ma. 27 sim_rst sim card reset 29 sim_data sim card data i/o 31 sim_clk sim card clock 33 sim_presence sim card detection following is the reference circuit about sim interface. we recommend an electro-static discharge device st ( www.st.com ) esda6v1w5 or on semi ( www.onsemi.com ) smf05c for ?esd anti?. the sim_presence pin is used for detecting the sim card removal. you can use the at command ?at+csdt? to set the simcard configure. for detail of this at command, please refer to document [1] : you can select the 8 pins sim card. the reference circuit about 8 pins sim card illustrates as SIM548_hd_v1.01 07.02.2007 48
SIM548 hardware design following figure. figure 19: sim interface reference circuit with 8pin sim card if you don?t use the sim card detection function, you can let the sim_presence pin nc or connect to the gnd. the reference circuit about 6 pins sim card illustrate as following figure. figure 20: sim interface reference circuit with 6pin sim card 3.11.2 design considerations for sim card holder for 6 pin sim card, we recommend to use amphenol c707-10m006 512 2 .you can visit http://www.amphenol.com for more information about the holder. SIM548_hd_v1.01 07.02.2007 49
SIM548 hardware design figure 21: amphenol c707-10m006 512 2 sim card holder table 18: pin description (a mphenol sim card holder) pin si g nal descri p tion c1 sim_vdd sim card power supply, it can identify automatically the sim card power mode one is 3.0v10%, another is 1.8v10%. current is about 10ma. c2 sim_rst sim card reset. c3 sim_clk sim card clock. c5 gnd connect to gnd. c6 vpp not connect. c7 sim_data sim card data i/o. for 8 pin sim card, we recommend to use molex 91228.you can visit http://www.molex.com for more information about the holder. SIM548_hd_v1.01 07.02.2007 50
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 51 figure 22: molex 91228 sim card holder table 19: pin description (molex sim card holder) pin signal description c1 sim_vdd sim card power supply, it can identify automatically the sim card power mode one is 3.0v10%, another is 1.8v10%. current is about 10ma. c2 sim_rst sim card reset. c3 sim_clk sim card clock. c4 gnd connect to gnd. c5 gnd connect to gnd. c6 vpp not connect. c7 sim_data sim card data i/o. c8 sim_presence detect sim card presence
SIM548 hardware design 3.12 lcd interface the gsm part of SIM548 provides a serial lc d display interface that supports serial communication with lcd device. these are composite pins that can be used as gpio ports or lcd display interface according to your application. when use as lcd interface, the following table is the pin define. lcd interface timing should be united with the lcd device. table 20: pin define of lcd interface pin (on board-to-board connector) name function 38 disp_cs display enable 40 disp_clk display clock for lcd 42 disp_data display data output 44 disp_d/c display data or command select 46 disp_rst lcd reset 3.13 general purpose input & output (gpio) table 21: gpio of the gsm part of SIM548 pin name function 19 status the status indication of the module general purpose output port 21 gpio0 general purpose input/output port 35 gpio1 general purpose input/output port the gsm part of SIM548 supports 2 general purpose input/output signal pins and output signal pins. both pins can be configured through at command ?at+cgpio? in users? application to high voltage level or low voltage level. for detail of this at command, please refer to document [1] . 3.14 adc the gsm part of SIM548 provide two auxiliary adc (general purpose analog to digital converter.) as voltage input pin, which can be used to detect the values of some external items such as voltage temperature etc. user can use at command ?at+radc? to read the voltage value added on adc pin. for detail of this at command, please refer to document [1] . SIM548_hd_v1.01 07.02.2007 52
SIM548 hardware design table 22: adc pin of the gsm part of SIM548 name pin (on board-to-board connector) input voltage ( v ) auxadc1 12 0 ? 2.4 3.15 behaviors of the ri line (serial port1 interface only) table 23: behaviours of the ri line state ri respond standby high voice calling change low then 1 change to high when establish calling. 2 use at command ath the ri pin changes to high.. 3 sender hang up, change to high data calling change low then 1 change to high when establish calling. 2 use at command ath the ri changes to high. sms when receive sms, the ri will change to low and hold low level about 120ms, then change to high. if the module is used as caller, signal ri will maintain high. but when it is used as receiver, following is timing of ri. figure 23: the gsm part of SIM548 services as receiver SIM548_hd_v1.01 07.02.2007 53
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 54 figure 24: the gsm part of SIM548 services as caller 3.16 network status indication led lamp the netlight (pin16) on the board- to-board connector can be used to drive a network status indication led lamp. the working state of this pin is listed in table; table 24: working state of netw ork status indication led pin state the gsm part of SIM548 function off the gsm part of SIM548 is not running 64ms on/ 800ms off the gsm part of SIM548 does not find the network 64ms on/ 3000ms off the gsm part of SIM548 find the network 64ms on/ 300ms off gprs communication we provide a reference circuitry for you, shown as the following figure:
SIM548 hardware design figure 25: reference circuit for network status led 3.17 buzzer the pin 23 on the board-to-board connector can be used to drive a buzzer to indicate incoming call. the output volume of buzzer can be set by ?at+crsl?. the reference circuit for buzzer as shown as the following figure: figure 26: reference circuit for buzzer SIM548_hd_v1.01 07.02.2007 55
SIM548 hardware design 4 gps application interface a gps receiver with high performance has been integrated to offer gps full function, it continuously tracks all satellites in view and provides accurate satellite position data. otherwise, the gps part can run separately even while the gsm part of SIM548 has been deregistered form the gsm network. 4.1 theory of operation the theory of operation is shown in the following figure: figure 27: theory of operation the SIM548 gps part is designed to use l1 frequency (c/a code) gps receiver and performs the entire gps signal processing, from antenna input to serial position data output. the processing step s involved are: rf section in the rf section the gps signal detected by the antenna is amplified, filtered andconverted to an intermediate frequency (if). an a/d converter converts the analogue intermediate frequency into a digital if signal. gps channels the received digital if signal bit stream is passed to the baseband section, where it is fed into the correlators. the function of the correlators is to ac quire and track the satellit e signals. there are 12 channels used in parallel, with each correlator looking for a characteristic prn code sequence in the bit stream. once the correlator has found a valid signal, pseudo range, carrier phase and orbit information can be extracted from the gps signal. SIM548_hd_v1.01 07.02.2007 56
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 57 gps core the on-board processor is running an algorithm th at calculates the position, velocity and time. this calculation is called navigation solution. once the navigation solution is calculated, it can be transformed into the desired coordinate system, e.g. latitude/altitude. data out the data of the navigation solution are available at the serial rs-232 interface. 4.2 technical data power consumption 210 mw with active antenna (continuous mode), 180mw with passive antenna (continuous mode) push-to-fix reduces power by as much as 98% note: this function need more software supporti ng form simcom ltd, please contact us for more detail. protocols sirf binary/nmea-0183 ai3/f (sirf interface) for a-gps rtcm (for dgps) position accuracy autonomous: < 10m sbas wass egnos: < 5m beacon dgps: < 3m receiver tracking: l1, c/a code channels: 20 update rate: default 1 hz tracking sensitivity: -157 2 dbm (see note) max. altitude: <60.000 ft (18,000 m) max. velocity: <1.000 knots (515 m/s )
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 58 protocol support: nmea-0183, sirf binary acquisition rate standalone hotstart: < 1 seconds, open sky warmstart: < 38 seconds, open sky coldstart: < 42 se conds, open sky a-gps gsm or 3g: <1s, open sky gsm or 3g: <24s, indoor cdma: <1s, open sky cdma: <18s, indoor note: 1) the receiver sensitivity above-mentioned is mostly related to antenna reference point, such as the antenna type, the antenna amplifier, the cu stomer application or the placement and the applied reference setup and so on. 2) a-gps: this function needs more supporting fo rm the mobile telecommunication network. a-gps support, based on the a-gps firmware. no w the standard version of the firmware in SIM548 does not support a-gps. 4.3 pin description table 25: pin description power supply pin name i/o description gps_vcc i two gps_vcc pins of the board-to-board connector are dedicated to connect the supply voltage. the power supply for gps whole part has to be a single voltage source it must be able to provide sufficient current of >150ma in the procedure of tracking satellites vmax= 5.0v vmin=3v vnorm=3.3v
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 59 gps_vrtc i apply 3v dc for backup rtc & sram. if unused, leave it open. vmax= 3.3v vmin=2.7v vnorm=3.0v gps_vant i the external dc power supply for an active gps antenna. it?s input voltage depends on the type of chosen active antenna, for the 5v type, it has to be connected to 5v external power supply; for the 3v type, it can be connected to the gps_vcc_rf pin directly which provides 2.85v dc. imax=25ma vmax=5v vmin=2.85v gps_vcc_rf o the optional power supply for 3.0v type active antenna. vmax=2.9v vmin=2.8v vnorm=2.85v imax=25ma gnd ground, shared with gsm part gpio pin name i/o description gps_gpio13 i/o reserved. it is reserved for customer specific applications. leave it open. gps_gpio14 i/o reserved. it is reserved for customer specific applications. leave it open. dual serial interface pin name i/o description gps_txa o serial data output for port a gps_rxa i serial data input for port a gps_txb o serial data out put for port b gps_rxb i serial data input for port b control signals pin name i/o description
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 60 gps_bootsel i for re-programming the flash, it must be set to high gps_m-rst i reset pin, active low. if used, it causes the module to reset; if not used, leave it open . note, if this pin is pulled down by a gpio, then the gpio must have the capability of inputting 1.5ma current. gps_timersync i an auxiliary clock input that supports alternate oscillator calibration systems. alternate functions are cs3 and gpio 15. reserved for a-gps. if not used, leave it open. gps_freq_xfer i reserved leave it open. gps_timemark o 1 pps timemark output for synchronizing to within 1 microsecond of gps time. if not used, leave it open. gps_wakeup i it only be used to wakeup the system from ptf mode. if not used, the user must connect this pin to the ground through a 0r resistor. nc all the pins named nc, do not use, leave it open. table 26: consolidated pin characteristics pin default direction 100k pull up gps_txa o gps_rxa i h gps_txb o gps_rxb i h 4.4 turn on the gps part of SIM548 to turn on the gps module, the gps_vcc must be higher than 2.3v, and should be kept on for
SIM548 hardware design 220ms at least. the theory of turning on is shown in the following figure: figure 28: turn on the gps module 4.5 the theory of the gps rtc circuit the rtc is very important for the gps module, because the data kept in the sram is depended on the vrtc. please keep the vrtc on if you want to use the function of hotstart, warmstart, or push-to-fix mode. there is a rtc ldo in our SIM548 module; it can provide 1.5v voltage to the sram. the theory of rtc circuit is shown in the following figure: SIM548_hd_v1.01 07.02.2007 61
SIM548 hardware design figure 29: theory of the gps rtc circuit 4.6 the theory of the reset circuit there is a reset ic in the SIM548 module. if the input of the reset ic is lower than 2.3v, the ?reset? pin will keep low; then the input voltage is higher than 2.3v, the reset ic will output a low level voltage for about 220ms as a reset signal. after that the reset output pin will be kept high. so, if the user wants to reset SIM548 gps part, the gps_m-rst should be pulled down longer than 10ms, and then pull it up . the theory of the reset circuit is shown in the figure: figure 30: theory of the reset circuit SIM548_hd_v1.01 07.02.2007 62
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 63 4.7 gps operation modes table 27: gps operation modes mode function normal operation the receiver is continuously running in normal mode, as long as the operating voltage vcc is supplied. position fixes are generated at the maximum update rate. this enables the receiver a warm - and hotstart. however, the cold- and warmstart times of receiver do not differ significantly under good visibility conditions. power down mode in this mode the user can cut o ff the gps_vcc to save more power consumption. but the vrtc must always be on. when the user resumes the gps_vcc, the receiver wakes up, a valid position can be computed in the normal hot-start time. push-to-fix mode (see note) in this mode the receiver will turn on every a given minutes (this period can be set form 10 minutes to 2 hours by software) to perform a system update consisting of position, time, ephemeris data refreshing and rtc calibration. when the ptf mode is enabled, upon power on or a new ptf cycle, the receiver will stay on full power until the good navigation solution is computed. the stand-by state will foll ow for the remainder of the period. for example, if it took 36 seconds to fix position and refresh ephemeris on the default period of 30 minutes, the receiver will sleep for the 29 minutes and 24 seconds. when the application needs a position report, it can toggle the gps_m-rst pin to wake up the receiver. when the receiver wakes up, a valid position can be computed in the normal hot-start time. 4.8 serial interface of the SIM548 gps part the gps part of the SIM548 module offers two serial interfaces, allows for different protocols to operate on each port. for example serial port a z 2-wire serial interface z includes the gps_rxa(receive) and gps_txa (transmit) lines z supported baud rate: 1200 115200 bps z protocol: default sirf binary ,57600bps
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 64 serial port b z 2-wire serial interface z includes the gps_rxb (receive) and txb (transmit) lines z supported baud rate: 1200 -115200bps but 4800 - 38400bps is a common rate range z protocol: default nmea ,4800bps z default output message: gga,gsa, gsv,rmc,vtg z update rate: default 1hz z datum wgs84 default (user configurable) notes: 1. both interfaces are configured as 8 data bits, no parity and 1 stop bit.. 2. the serial ports also can be configured to ad apt to customer specific ap plications, such as for dgps, and so on. more detail please contact with simcom ltd. 3. we can also help the user to change the prot ocol and baud rate of the two serial ports by different firmware. for more deta il please contact simcom ltd. 4.9 start-up procedure the start-up strategy of the SIM548 gps part depends on the last position, current time and ephemeris data, that the receiver has stored the external sram memory. there are three different start-up procedures: 4.9.1 coldstart the coldstart takes place when the receiver has no kn owledge of its last position or time. in this case the gps rtc has not been running and no valid ephemeris data or almanac data is available (the receiver has never been navigating or no battery backup memory available). 4.9.2 warmstart this start-up procedure is perform ed whenever the receiver is able to use the valid almanac data, and has not in an important manner moved since the last valid position calculation. this procedure starts if the receiver has been shut off for more than 2 hours, but the last position, time and almanac are still acknowledged. this procedure is able to announce the current visible satellites in advance. however, since ephemeris data are not available or cannot longer be used, the receiver has to wait for the ephemeris broadcast to complete.
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 65 4.9.3 hotstart hotstart is performed whenever the receiver still has access to valid ephemeris data and exact time. this procedure starts if the receiver has been sh ut off for less than 2 hours and the gps rtc has been running during that time. furthermore, during the previous session, the receiver must have been navigating (to allow it to decode and store ephemeris data). in hotstart, the receiver can announce in advance the currently visible satellit es, and is theref ore able to quickly obtain and track the signal. due to the fact that ephemeris is already known, there is no need to wait for the ephemeris broadcast to complete.
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 66 5 antenna interface 5.1 gsm antenna the rf interface has an impedance of 50 ? . to suit the physical design of individual applications SIM548 offers two alternatives: z recommended approach: antenna connector on the component side of the pcb z antenna pad and grounding plane placed on the bottom side. to minimize the loss on the rf cable, it need be very careful to choose rf cable. we recommend the insertion loss should be meet following requirement: z gsm850/egsm900<1db z dcs1800/pcs1900<1.5db 5.1.1 antenna connector SIM548 use murata?s mm9329-2700 rf connector on the module side, we recommend user use murata?s mxtk92xxxxx as matching connector on the application side. please refer to appendix for detail info about murata?s mxtk92xxxxx. 5.1.2 antenna pad the antenna can be soldered to the pad, or attach ed via contact springs. to help you to ground the antenna, SIM548 comes with a grounding plane lo cated close to the antenna pad. the antenna pad of SIM548 is shown as the following figure:
SIM548 hardware design figure 31: rf connector and rf pad the gsm part of SIM548 material properties: the gsm part of SIM548 pcb material: fr4 antenna pad: gold plated pad SIM548_hd_v1.01 07.02.2007 67
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 68 5.1.3 module rf output power table 28: the gsm part of SIM548 conducted rf output power frequency max min gsm850 33dbm 2db 5dbm5db egsm900 33dbm 2db 5dbm5db dcs1800 30dbm 2db 0dbm5db pcs1900 30dbm 2db 0dbm5db 5.1.4 module rf receive sensitivity table 29: the gsm part of SIM548 co nducted rf conducted receive sensitivity frequency receive sensitivity gsm850 < -106dbm egsm900 < -106dbm dcs1800 < -106dbm pcs1900 < -106dbm 5.1.5 module operating frequencies table 30: the gsm part of SIM548 operating frequencies frequency receive transmit gsm850 869 894mhz 824 849 mhz egsm900 925 960mhz 880 915mhz dcs1800 1805 1880mhz 1710 1785mhz pcs1900 1930 1990mhz 1850 1910mhz 5.2 gps antenna 5.2.1 gps antenna connection SIM548 provide an antenna connector for customer to connect gps antenna via a proper
SIM548 hardware design microwave coaxial cable. about the connector?s type and the matched microwave coaxial cable, please refer to 5.1.1. the location of the gps antenna connector can be found in the following figure. figure 32: rf connector 5.2.2 gps antenna choice consideration to obtain excellent gps reception performance, a good antenna will always be required. the antenna is the most critical item for successful gps reception in a weak signal environment. proper choice and placement of the antenna will ensure that satellites at all elevations can be seen, and therefore, accurate fix measurements are ob tained. most customers contract with antenna design houses to properly measure the radiation pattern of the final mounted configuration in a plastic housing with associated components near the antenna. linear antennas are becoming more popular, and the gain is reasonable, since a smaller ground plane can be used. chose a linear antenna with a reasonably uniform hemispherical ga in pattern of >-4dbi. use of an antenna with lower gain than this will give less than desirable results. please note that a rhcp antenna with a gain of -3dbic, equates to a linear polarized an tenna of -0dbi. proper ground plane sizing is a critical consideration for small gps antennas. prop er placement of the gps antenna should always be the first consideration in integrating the SIM548 gps module. SIM548_hd_v1.01 07.02.2007 69
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 70 if the customer?s design will allo w for a ceramic rhcp patch antenna with an appropriately sized ground plane, and the patch is normally oriented towards the sky, then that particular solution usually works the best. please note that if the patch antenna ground plane is less than 60x60mm, then compromises to the beam width and gain pattern could result. usually the gain becomes very directional, and looses several db of performance. since results can vary, measuring the antenna radiation pattern in the final housing in an appropriate anechoic chamber will be required. some customers do not have the size availability to implement a patch antenna approach. in that instance, use of a linear polarized (lp) antenna is the next best alternative. there are new ceramic lp antennas on the market that exhibit reasonable gain characteristics once properly mounted in the housing, and when mated to an appropriate sized ground. that is the key point to consider here. ?when mated to an appropriate sized ground?. usually, the ground plane requirements are smaller for a lp antenna when compared to a patch, but once again, proper testing in an anechoic chamber is a mandatory requirement. these ceramic elements will need to be located near the end of the ground plane, and will require several mm of clearance between the closest component. it is important to note that use of a lp antenna will result in a minimum of 3db of gain loss when compared to a rhcp antenna at a defined elevation. this is due to the right hand gain rule of antenna propagation. use of pifa antenna is another lp possibility, but the pifa usually exhibits a considerable amount of gain nulls, or ?holes? in the radiation pattern. this will be undesirable for obtaining a low circular error probability (cep), since the an tenna may not allow the receiver to capture the desired satellite at the ideal orientation due to these noted gain nulls. once again, careful testing in an appropriate anechoic chamber is required. if the customer?s design is for automotive applicat ions, then an active antenna can be used and located on top of the car in order for guarantee the best signal quality. here are two gps antenna manufacturers be recommended, you can visit their websites for details, http://www.inpaq.com.tw and http://www.passivecomponent.com . but the gps antenna choice should base on the designing product and other conditions. for detailed antenna designing consideration, please refer to related antenna vendor?s design
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 71 recommendation. the antenna vendor will offer further technical support and tune their antenna characteristic to achieve successful gps recepti on performance depends on the customer?s design.
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 72 6 electrical, reliability and radio characteristics 6.1 absolute maximum ratings absolute maximum rating for power supply and voltage on digital and analog pins of SIM548 are list in table31 and table 32. table 31: absolute maxi mum ratings (gsm part) parameter min max unit peak current of power supply 0 4.0 a rms current of power supply (during one tdma- frame) 0 0.7 a voltage at digital pins -0.3 3.3 v voltage at analog pins -0.3 3.0 v voltage at digit/analog pins in power down mode -0.25 0.25 v table 32: absolute maximum ratings (gps part) parameter min max unit voltage at gps_vcc -0.3 5 v current at gps_vcc_rf 25 ma 6.2 operating temperatures the operating temperature is listed in table33: table 33: SIM548 operating temperature parameter min typ max unit ambient temperature -20 25 55 restricted operation* -30 to -20 55 to 80 storage temperature -40 +85 * SIM548 can work, but the deviation fro m the gsm specification may occur.
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 73 6.3 power supply rating table 34: power supply rating (gsm part) parameter description conditions min typ max unit supply voltage voltage must stay within the min/max values, including voltage drop, ripple, and spikes. 3.4 4.0 4.5 v voltage drop during transmit burst normal condition, power control level for pout max 400 mv vbat voltage ripple normal condition, power control level for pout max @ f<200khz @ f>200khz 50 2 mv average supply current) power down mode sleep mode ( bs-pa-mfrms=5 ) 35 2.5 ua ma idle mode (not connect console gsm 850/ egsm 900 dcs 1800/ pcs 1900 23 23 ma idle mode connect console gsm 850/ egsm 900 dcs 1800/ pcs 1900 33 33 ma talk mode gsm 850/ egsm 900 dcs 1800/ pcs 1900 260 200 ma data mode, gprs(3 rx,2tx) gsm 850/ egsm 900 dcs 1800/ pcs 1900 470 340 ma ivbat data mode, gprs(4 rx,1tx) gsm 850/ egsm 900 dcs 1800/ pcs 1900 275 220 ma
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 74 peak supply current (during transmission slot every 4.6ms) power control level 2 3.1 a table 35: power supply rating (gps part) parameter description conditions min typ max unit gps_vcc supply voltage 3.0 3.3 5 v igps_vcc average supply current continuous mode (with antenna feeding on gps_vcc_rf) 65 110 ma note: basing on current standard gsw3 soft version, the power saving mode of gps part is not available, that results 65 ma igps_vcc remained while the gps receiver is running in normal mode. 6.4 current consumption 6.4.1 the current consumptio n of the SIM548 gsm part. table 36: current consumption (gsm part) voice call gsm 850/ egsm 900 @power level #5 <350ma,typical 260ma @power level #10,typical 130ma @power level #19,typical 86ma dcs 1800/ pcs 1900 @power level #0 <300ma,typical 200ma @power level #10,typical 87ma @power level #15,typical 80ma gprs data data mode, gprs ( 1 rx,1 tx )class 8 gsm 850/ egsm 900 @power level #5 <350ma,typical 260ma @power level #10,typical 125ma @power level #19,typical 84ma dcs 1800/ pcs 1900 @power level #0 <300ma,typical 200ma
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 75 @power level #10,typical 83ma @power level #15,typical 76ma data mode, gprs ( 3 rx, 2 tx )class 10 gsm 850/ egsm 900 @power level #5 <550ma,typical 470ma @power level #10,typical 225ma @power level #19,typical 142ma dcs 1800/ pcs 1900 @power level #0 <450ma,typical 340ma @power level #10,typical 140ma @power level #15,typical 127ma data mode, gprs ( 4 rx,1 tx )class 8 gsm 850/ egsm 900 @power level #5 <350ma,typical 270ma @power level #10,typical 160ma @power level #19,typical 120ma dcs 1800/ pcs 1900 @power level #0 <300ma,typical 220ma @power level #10,typical 120ma @power level #15,typical 113ma class 10 is default set when the module work at data translation mode, the module can also work at class 8 set by at command. 6.4.2 the current consumption of the SIM548 gps part to save more current consumption, we suggest the user to design their system in one of the two modes: 1. power down mode; 2.push-to-fix mode 6.4.2.1 power down mode the circuit of this mode is shown in the figure:
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 76 figure 33: power down mode when the user wants to save more current consumption of the gps part, he can pull down the power_ctrl of the mcu to stop the ldo outputting. and this operation will cut off the power of the gps part. note that the vrtc must be kept on. 6.4.2.2 push-to-fix mode the circuit of this mode is shown in figure 34.
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 77 figure 34: push-to-fix mode the user can also save power by sending the ?push-to-fix? command to the gps part of the SIM548. the push-to-fix mode puts the receiver into a background duty cycle mode that provides a periodic refresh of position, gps time, ephemeris, and rtc calibration every 10 seconds to 2 hours. typical ptf operation is illustrated in figure (35). the ptf period is 30 minutes by default but can be anywhere between 10 seconds and 2 hours. when the ptf mode is enabled, upon power on or a new ptf cycle, the receiv er will stay on full power until the good navigation solution is computed. the stand-by state will follow for the remainder of the period. if it took 36 seconds to fix position and refresh ephemeris on the default period of 30 minutes, the receiver will sleep for the 29 minutes and 24 seconds. when the application needs a position report, it can togg le the gps_m-rst pin to wake up the receiver. when the receiver wakes up, it can produce a valid position in the normal hot-start time.
SIM548 hardware design power consumption in the ptf mode again, a typical setting of 1800 seconds ptf interval is considered. assuming it takes 8 seconds to compute a good position since the start of a cycle, the average current and power consumption of each typical cycle is iavg = (65 ma * 8160 ms + 1 ma * 1791840 ms) / 1800 seconds = 1.290 ma pavg = 3.3 v * 1.290 ma = 4.257 mw figure 35: power consumption in the ptf mode note: when the user wants to use power down mode or push-to-fix mode, the rtc battery must be 2.5v+.if the rtc battery level is lower than 2.5v, the SIM548 module will not go into ptf mode. 6.5 electrostatic discharge the gsm engine is not protected against electrostatic discharge (esd) in general. therefore, it is subject to esd handing precautions that typical ly apply to esd sensitive components. proper esd handing and packaging procedures must be applied throughout the processing, handing and operation of any application using a SIM548 module. the measured values of SIM548 ar e shown as the following table: SIM548_hd_v1.01 07.02.2007 78
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 79 table 37: the esd endure statue measured table (temperature: 25 , humidity: 45% ) part contact discharge air discharge vbat,gnd 4kv 8kv kbr0-4, dtr, rxd, txd, rts, disp_data, disp_clk 2kv 4kv antenna port 2kv 4kv other port 1kv
SIM548 hardware design 7 mechanics this chapter describes the mechanical dimensions of SIM548. 7.1 mechanical dimensions of SIM548 following shows the mechanical dimensions of SIM548 (top view and side view). figure 36: SIM548 top view and side view SIM548_hd_v1.01 07.02.2007 80
SIM548 hardware design 7.2 mounting SIM548 onto the application platform use the board to board connector and four mounting pads to fix the SIM548 onto customer platform. 7.3 board-to-board connector we recommend user adopt molex company?s 55201-087 8 type as the board to board connector. these high density smt connector s are designed for parallel pcb- to-pcb applications. they are ideal for use in vcrs, notebook pcs, cordless telephones, mobile phones, audio/visual and other telecommunications equipment where reduced size and weight are important. following is the parameter of 55201-087 8 . for more, you can login http://www.molex.com . 7.3.1 mechanical dimensions of 55201-087 8 figure 37: 55201-087 8 board-to-board connector SIM548_hd_v1.01 07.02.2007 81
SIM548 hardware design figure 38: board to boar d connector physical photo note the connector54363-0878 is used in socket side (SIM548 module) and 55201-0878 is used pin side (user side). SIM548_hd_v1.01 07.02.2007 82
SIM548 hardware design 7.3.2 adapter cabling figure 39: mm9329-2700b figure 40: rf connector mxtk for more information about the connector, please visit http://www.murata.com/ SIM548_hd_v1.01 07.02.2007 83
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 84 7.3.3 pin assignment of board -to-board connector of SIM548 table 38: pin assignment of SIM548 pin no. pin name pin no. pin name 1 vbat 2 gnd 3 vbat 4 gnd 5 vbat 6 gnd 7 vbat 8 gnd 9 vbat 10 gnd 11 vchg 12 adc0 13 temp_bat 14 vrtc 15 nc 16 netlight 17 pwrkey 18 kbc0 19 status 20 kbc1 21 gpio0 22 kbc2 23 buzzer 24 kbc3 25 sim_vdd 26 kbc4 27 sim_rst 28 kbr0 29 sim_data 30 kbr1 31 sim_clk 32 kbr2 33 sim_presence 34 kbr3 35 gpio1 36 kbr4 37 dcd 38 disp_cs 39 dtr 40 disp_clk 41 rxd 42 disp_data 43 txd 44 disp_d/c 45 rts 46 disp_rst 47 cts 48 dbg_rxd 49 ri 50 dbg_txd 51 agnd 52 agnd 53 spk1p 54 mic1p 55 spk1n 56 mic1n 57 spk2p 58 mic2p 59 spk2n 60 mic2n 61 gps_timemark 62 gps_wakeup 63 gps_freq_xfer 64 gps_bootsel 65 gps_timersync 66 gps_m-rst
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 85 67 nc 68 gps_txb 69 nc 70 gps_rxb 71 nc 72 gps_txa 73 gps_gpio13 74 gps_rxa 75 gps_gpio14 76 gps_vcc_rf 77 gps_vrtc 78 gps_vant 79 gps_vcc 80 gps_vcc
SIM548 hardware design the following figure is a top-view of SIM548 module. with the indication of pin 1, 2, 79 and 80. figure 41: physical SIM548 SIM548_hd_v1.01 07.02.2007 86
SIM548 hardware design SIM548_hd_v1.01 07.02.2007 87 figure 42: reference circuit with external mcu (example application)
contact us: shanghai simcom ltd. add: sim technology building, no. 700, yishan road, shanghai,p. r. china 200233 tel: +86 21 5427 8900 fax: +86 21 5427 6035 url: www.sim.com

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