User's Manual

XT55/56 Hardware Interface Description
Confidential / Released
s
XT55/56_hd_v02.06a Page 4 of 125 17.12.2004
3.7 Summary of state transitions (except SLEEP mode)...........................................53
3.8 RTC backup for GSM part of XT55/56.................................................................54
3.9 Serial interfaces of the XT55/56 GSM part ..........................................................55
3.9.1 Features supported on the first serial interface of GSM part (ASC0) ....55
3.9.2 Features supported on the second serial interface of
GSM part (ASC1)...................................................................................56
3.9.3 ASC0 and ASC1 configuration...............................................................56
3.10 Audio interfaces ...................................................................................................57
3.10.1 Microphone circuit..................................................................................58
3.10.2 Speech processing ................................................................................59
3.10.3 DAI timing ..............................................................................................59
3.11 SIM interface........................................................................................................61
3.11.1 Requirements for using the GSM_CCIN pin ..........................................62
3.11.2 Design considerations for SIM card holder............................................63
3.12 Control signals .....................................................................................................64
3.12.1 Inputs .....................................................................................................64
3.12.2 Outputs ..................................................................................................65
3.12.2.1 Synchronization signal...........................................................65
3.12.2.2 Using the GSM_SYNC pin to control a status LED ...............66
3.12.3 Behavior of the GSM_RING0 line (ASC0 interface only).......................68
4 GPS application interface...........................................................................................70
4.1 Theory of operation..............................................................................................70
4.2 Technical data .....................................................................................................71
4.3 GPS operating modes .........................................................................................72
4.3.1 Trickle Power mode ...............................................................................73
4.3.2 Comparison of Trickle Power and Push-to-Fix mode ............................74
4.4 Power supply of the XT55/56 GPS part...............................................................75
4.5 General purpose input/output ..............................................................................75
4.6 Serial interfaces of the XT55/56 GPS part...........................................................76
4.7 GPS control signals .............................................................................................76
4.8 Receiver architecture...........................................................................................77
4.9 Operation procedure............................................................................................78
4.10 Start-up procedures .............................................................................................79
4.10.1 Coldstart.................................................................................................79
4.10.2 Warmstart ..............................................................................................79
4.10.3 Hotstart ..................................................................................................79
5 GSM and GPS antenna interfaces .............................................................................80
5.1 GSM antenna installation.....................................................................................80
5.1.1 GSM antenna connector ........................................................................80
5.1.2 GSM antenna pad..................................................................................82
5.2 Installing the GPS antenna ..................................................................................82
5.3 Hirose antenna connector....................................................................................83
6 Electrical, reliability and radio characteristics.........................................................87
6.1 Absolute maximum ratings ..................................................................................87
6.2 Operating temperatures.......................................................................................87
6.3 Pin description .....................................................................................................89
6.4 Power supply ratings ...........................................................................................95
6.4.1 Current consumption during GSM transmit burst...................................97
6.5 Electrical characteristics of the voiceband part..................................................102
6.5.1 Setting audio parameters by AT commands........................................102
6.5.2 Audio programming model...................................................................103
6.5.3 Characteristics of audio modes............................................................104