User Manual

XT55/56 Hardware Interface Description
Confidential / Preliminary
s
XT55/56_hd_v02.96 Page 4 of 125 18.08.2005
3.8 RTC Backup for GSM Part of XT55/56................................................................56
3.9 Serial Interfaces of the XT55/56 GSM Part .........................................................57
3.9.1 Features Supported on the first Serial Interface of GSM Part (ASC0)...57
3.9.2 Features Supported on the second Serial Interface of GSM Part (ASC1)
...............................................................................................................58
3.9.3 ASC0 and ASC1 Configuration..............................................................58
3.10 Audio Interfaces...................................................................................................59
3.10.1 Microphone Circuit.................................................................................60
3.10.2 Speech Processing................................................................................61
3.10.3 DAI Timing .............................................................................................61
3.11 SIM Interface .......................................................................................................63
3.11.1 Requirements for Using the GSM_CCIN Pin .........................................64
3.11.2 Design Considerations for SIM Card Holder..........................................65
3.12 Control Signals ....................................................................................................66
3.12.1 Inputs .....................................................................................................66
3.12.2 Outputs ..................................................................................................67
3.12.2.1 Synchronization Signal ..........................................................................67
3.12.2.2 Using the GSM_SYNC Pin to Control a Status LED..............................68
3.12.3 Behavior of the GSM_RING0 Line (ASC0 Interface only) .....................70
4 GPS Application Interface ..........................................................................................71
4.1 Theory of Operation.............................................................................................71
4.2 Technical Data.....................................................................................................72
4.3 GPS Operating Modes.........................................................................................73
4.3.1 Trickle Power Mode ...............................................................................74
4.3.2 Comparison of Trickle Power and Push-to-Fix Mode ............................75
4.4 Power Supply of the XT55/56 GPS Part..............................................................76
4.5 General Purpose Input/Output (GPIO) ................................................................76
4.6 Serial Interfaces of the XT55/56 GPS Part ..........................................................77
4.7 GPS Control Signals............................................................................................77
4.8 Receiver Architecture ..........................................................................................78
4.9 Operation Procedure ...........................................................................................79
4.10 Start-up Procedures.............................................................................................80
4.10.1 Coldstart.................................................................................................80
4.10.2 Warmstart ..............................................................................................80
4.10.3 Hotstart ..................................................................................................80
5 GSM and GPS Antenna Interfaces.............................................................................81
5.1 GSM Antenna Installation ....................................................................................81
5.1.1 GSM antenna Connector .......................................................................81
5.1.2 GSM Antenna Pad .................................................................................83
5.2 Installing the GPS Antenna..................................................................................83
5.3 Hirose Antenna Connector ..................................................................................84
6 Electrical, Reliability and Radio Characteristics......................................................88
6.1 Absolute Maximum Ratings .................................................................................88
6.2 Operating Temperatures......................................................................................88
6.3 Pin Description.....................................................................................................90
6.4 Power Supply Ratings .........................................................................................96
6.4.1 Current Consumption during GSM Transmit Burst ................................98
6.5 Electrical Characteristics of the Voiceband Part................................................103
6.5.1 Setting Audio Parameters by AT Commands ......................................103
6.5.2 Audio Programming Model ..................................................................104
6.5.3 Characteristics of Audio Modes ...........................................................105
6.5.4 Voiceband Receive Path......................................................................106