hardware design v1 00 2

Smart Machine Smart Decision
SIM900R_Hardware Design_V1.00 3 2012-07-20
Contents
Contents.................................................................................................................................................................... 3
Version History........................................................................................................................................................ 7
1 Introduction....................................................................................................................................................... 8
2 SIM900R Overview........................................................................................................................................... 8
2.1 SIM900R Key Features ............................................................................................................................ 8
2.2 Operating Modes .................................................................................................................................... 10
2.3 SIM900R Functional Diagram ................................................................................................................11
3 Package Information ...................................................................................................................................... 12
3.1 Pin out Diagram...................................................................................................................................... 12
3.2 Pin Description ....................................................................................................................................... 13
3.3 Package Dimensions............................................................................................................................... 15
4 Application Interface...................................................................................................................................... 16
4.1 Power Supply.......................................................................................................................................... 16
4.1.1 Minimizing Voltage Drop of VBAT................................................................................................... 17
4.1.2 Monitoring Power Supply ................................................................................................................... 17
4.2 Power on/down Scenarios ...................................................................................................................... 17
4.2.1 Power on SIM900R............................................................................................................................. 17
4.2.2 Power down SIM900R........................................................................................................................ 18
4.2.3 Restart SIM900R by PWRKEY Pin.................................................................................................... 20
4.3 Power Saving Mode................................................................................................................................ 20
4.3.1 Minimum Functionality Mode ............................................................................................................ 20
4.3.2 Sleep Mode 1 (AT+CSCLK=1) .......................................................................................................... 21
4.3.3 Wake Up SIM900R from Sleep Mode 1 (AT+CSCLK=1)................................................................. 21
4.3.4 Sleep Mode 2 (AT+CSCLK=2) .......................................................................................................... 21
4.3.5 Wake Up SIM900R from Sleep Mode 2 (AT+CSCLK=2)................................................................. 22
4.4 RTC Backup ........................................................................................................................................... 22
4.5 Serial Interfaces ...................................................................................................................................... 23
4.5.1 Function of Serial Port and Debug Port .............................................................................................. 24
4.5.2 Software Upgrade and Debug ............................................................................................................. 25
4.6 Audio Interfaces ..................................................................................................................................... 25
4.6.1 Speaker Interface Configuration ......................................................................................................... 25
4.6.2 Microphone Interfaces Configuration ................................................................................................. 26
4.6.3 Earphone Interface Configuration....................................................................................................... 27
4.6.4 Audio Electronic Characteristics......................................................................................................... 27
4.7 SIM Card Interface ................................................................................................................................. 28
4.7.1 SIM Card Application......................................................................................................................... 28
4.7.2 Design Considerations for SIM Card Holder...................................................................................... 29
4.8 LCD Display/SPI Interface..................................................................................................................... 30
4.9 Keypad Interface .................................................................................................................................... 31
4.10 ADC........................................................................................................................................................ 31
4.11 RI Behaviours......................................................................................................................................... 32
4.12 Network Status Indication ...................................................................................................................... 33