SimCom SIM900D EVB, Hardware Design

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SIM900D Hardware Design
Contents
Contents .....................................................................................................................................................................3
Version history...........................................................................................................................................................7
1 Introduction.............................................................................................................................................................8
1.1 Related Documents .......................................................................................................................................8
1.2 Terms and Abbreviations...............................................................................................................................8
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 ..............................................................................................................29
3.5.3 Implemented charging technique.......................................................................................................30
3.5.4 Operating modes during charging .....................................................................................................31
3.5.5 Charger requirements ........................................................................................................................32
3.6 Summary of State Transitions (except SLEEP mode).................................................................................32
3.7 Power Saving ..............................................................................................................................................33
3.7.1 Minimum Functionality Mode ..........................................................................................................33
3.7.2 Sleep Mode I (CSCLK=1).................................................................................................................33
3.7.3 Wake Up SIM900D from SLEEP Mode (CSCLK=1) ......................................................................34
3.7.4 Sleep Mode II (CSCLK=2) ...............................................................................................................34
3.7.5 Wake Up SIM900D from SLEEP Mode (CSCLK=2) ......................................................................34
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
SIM900D_Hardware Design_V1.04 2010.10.09
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