Specifications

XT65/XT75 Hardware Interface Description
Contents
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XT65_XT75_HD_v01.001 Page 4 of 133 2007-1-8
Confidential / Released
3.5.6 Implemented Charging Technique................................................................................. 44
3.5.7 Operating Modes during Charging................................................................................. 45
3.6 Power Saving ................................................................................................................................ 47
3.6.1 Network Dependency of SLEEP Modes........................................................................ 48
3.6.2 Timing of the CTS0 Signal in CYCLIC SLEEP Mode 7 ................................................. 48
3.6.3 Timing of the RTS0 Signal in CYCLIC SLEEP Mode 9 ................................................. 49
3.7 Summary of State Transitions (Except SLEEP Mode).................................................................. 50
3.8 RTC Backup.................................................................................................................................. 51
3.9 SIM Interface................................................................................................................................. 52
3.9.1 Installation Advice.......................................................................................................... 52
3.10 Serial Interface ASC0.................................................................................................................... 53
3.11 USB Interface................................................................................................................................ 55
3.12 I
2
C Interface .................................................................................................................................. 56
3.13 SPI Interface.................................................................................................................................. 57
3.14 Audio Interfaces ............................................................................................................................ 59
3.14.1 Speech Processing........................................................................................................ 60
3.14.2 Microphone Circuit......................................................................................................... 60
3.14.2.1 Single-ended Microphone Input..................................................................................... 60
3.14.2.2 Differential Microphone Input......................................................................................... 61
3.14.2.3 Line Input Configuration with OpAmp............................................................................ 62
3.14.3 Loudspeaker Circuit.......................................................................................................63
3.14.4 Digital Audio Interface (DAI) .......................................................................................... 63
3.14.4.1 Master Mode.................................................................................................................. 64
3.14.4.2 Slave Mode.................................................................................................................... 66
3.15 Analog-to-Digital Converter (ADC)................................................................................................ 68
3.16 GPIO Interface .............................................................................................................................. 69
3.16.1 Using the GPIO10 Pin as Pulse Counter....................................................................... 69
3.17 Control Signals.............................................................................................................................. 70
3.17.1 Synchronization Signal .................................................................................................. 70
3.17.2 Using the SYNC Pin to Control a Status LED................................................................ 71
3.17.3 Behavior of the RING0 Line (ASC0 Interface only) ....................................................... 72
3.17.4 PWR_IND Signal ........................................................................................................... 72
4 GPS Application Interface..................................................................................................................... 73
4.1 Operating Principles...................................................................................................................... 73
4.1.1 Basic Operation Cycle ................................................................................................... 73
4.1.2 GPS Start-Up................................................................................................................. 74
4.1.2.1 Cold Start....................................................................................................................... 75
4.1.2.2 Warm Start..................................................................................................................... 75
4.1.2.3 Hot Start......................................................................................................................... 75
4.1.3 Supported Protocols ...................................................................................................... 76
4.1.3.1 NMEA Protocol .............................................................................................................. 76
4.1.3.2 UBX Binary Protocol......................................................................................................76
4.1.3.3 RTCM Protocol .............................................................................................................. 76
4.1.4 Position Accuracy Improvement Possibilities ................................................................ 77
4.1.4.1 Differential GPS (DGPS) ............................................................................................... 77
4.1.4.2 Satellite Based Augmentation Systems (SBAS)............................................................ 77