Table Of Contents; Contents - SIM Tech SIM900D HD Manual

SIM900D Hardware Design

Contents

Contents .....................................................................................................................................................................3
Version history...........................................................................................................................................................7
1 Introduction.............................................................................................................................................................8
1.1 Related Documents .......................................................................................................................................8
1.2 Terms and Abbreviations...............................................................................................................................9
1.3 Safety Precautions ....................................................................................................................................... 11
2 SIM900D Overview..............................................................................................................................................13
2.1 SIM900D Key Features...............................................................................................................................13
2.2 SIM900D Functional Diagram....................................................................................................................15
2.3 SIM900D Evaluation Board........................................................................................................................16
3 Application Interface.............................................................................................................................................18
3.1 SIM900D Pin Description ...........................................................................................................................18
3.2 Operating Modes .........................................................................................................................................21
3.3 Power Supply ..............................................................................................................................................22
3.3.1 Power Supply Pins.............................................................................................................................23
3.3.2 Minimizing Power Losses .................................................................................................................23
3.3.3 Monitoring Power Supply .................................................................................................................24
3.4 Power Up and Power Down Scenarios........................................................................................................24
3.4.1 Turn on SIM900D .............................................................................................................................24
3.4.2 Turn Off SIM900D............................................................................................................................26
3.4.3 Restart SIM900D 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 modes during charging .....................................................................................................31
3.5.5 Charger requirements ........................................................................................................................32
3.6 Power Saving ..............................................................................................................................................32
3.6.1 Minimum Functionality Mode ..........................................................................................................33
3.6.2 Sleep Mode (Slow Clock Mode) .......................................................................................................33
3.6.3 Wake Up SIM900D from SLEEP Mode ...........................................................................................33
3.7 Summary of State Transitions (except SLEEP mode).................................................................................33
3.8 RTC Backup ................................................................................................................................................34
3.9 Serial Interfaces...........................................................................................................................................36
3.9.1 Function of serial port & debug port supporting ...............................................................................37
3.9.2 Software Upgrade and Software Debug ............................................................................................38
3.10 Audio Interfaces ........................................................................................................................................40
3.10.1 Speaker Interface Configuration......................................................................................................41
3.10.2 Microphone Interfaces Configuration .............................................................................................42
SIM900D_HD_V1.02
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09.04.2010