User's Manual
Table Of Contents
- Contents
- Version history
- 1 Introduction
- 2 SIM900B Overview
- 3 Application Interface
- 3.1 SIM900B Pin Description
- 3.2 Operating Modes
- 3.3 Power Supply
- 3.4 Power Up and Power Down Scenarios
- 3.5 Power Saving
- 3.6 Summary of State Transitions (except SLEEP mode)
- 3.7 RTC Backup
- 3.8 Serial Interfaces
- 3.9 Audio Interfaces
- 3.10 Buzzer
- 3.11 SIM Card Interface
- 3.12 LCD Display Interface
- 3.13 Keypad Interface
- 3.14 ADC
- 3.15 Behaviors of the RI
- 3.16 Network Status Indication
- 3.17 General Purpose Input Output (GPIO)
- 4 Antenna Interface
- 5 Electrical, Reliability and Radio Characteristics
- 6 Mechanics
SIM900B 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 Caution.............................................................................................................................................11
2 SIM900B Overview ..............................................................................................................................................13
2.1 SIM900B Key Features...............................................................................................................................13
2.2 SIM900B Functional Diagram ....................................................................................................................15
2.3 SIM900B Evaluation Board ........................................................................................................................16
3 Application Interface.............................................................................................................................................18
3.1 SIM900B 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 .................................................................................................................24
3.3.3 Monitoring Power Supply .................................................................................................................24
3.4 Power Up and Power Down Scenarios........................................................................................................24
3.4.1 Turn on SIM900B..............................................................................................................................24
3.4.2 Turn Off SIM900B............................................................................................................................26
3.4.3 Restart SIM900B Using the PWRKEY Pin.......................................................................................28
3.5 Power Saving ..............................................................................................................................................28
3.5.1 Minimum Functionality Mode ..........................................................................................................28
3.5.2 Sleep Mode (Slow Clock Mode) .......................................................................................................29
3.5.3 Wake Up SIM900B from SLEEP Mode ...........................................................................................29
3.6 Summary of State Transitions (except SLEEP mode).................................................................................29
3.7 RTC Backup ................................................................................................................................................30
3.8 Serial Interfaces...........................................................................................................................................31
3.8.1 Function of serial port & debug port supporting ...............................................................................33
3.8.2 Software Upgrade and Software Debug ............................................................................................34
3.9 Audio Interfaces ..........................................................................................................................................35
3.9.1 Speaker Interface Configuration........................................................................................................36
3.9.2 Microphone Interfaces Configuration ...............................................................................................37
3.9.3 Earphone Interface Configuration .....................................................................................................37
3.9.4 Referenced Electronic Characteristic ................................................................................................38
3.10 Buzzer .......................................................................................................................................................39
3.11 SIM Card Interface....................................................................................................................................40
3.11.1 SIM Card Application .....................................................................................................................40
3.11.2 Design Considerations for SIM Card Holder ..................................................................................41
SIM900B_HD_V1.03 24.06.2010
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