hardware design v1 00 2
Table Of Contents
- Contents
- Version History
- 1 Introduction
- 2 SIM900R Overview
- 3 Package Information
- 4 Application Interface
- 4.1 Power Supply
- 4.2 Power on/down Scenarios
- 4.3 Power Saving Mode
- 4.4 RTC Backup
- 4.5 Serial Interfaces
- 4.6 Audio Interfaces
- 4.7 SIM Card Interface
- 4.8 LCD Display/SPI Interface
- 4.9 Keypad Interface
- 4.10 ADC
- 4.11 RI Behaviours
- 4.12 Network Status Indication
- 4.13 General Purpose Input/Output (GPIO)
- 4.14 External Reset
- 4.15 PWM
- 4.16 I2C Bus
- 4.17 Antenna Interface
- 5 Electrical, Reliability and Radio Characteristics
- 5.1 Absolute Maximum Ratings
- 5.2 Recommended Operating Conditions
- 5.3 Digital Interface Characteristics
- 5.4 SIM Card Interface Characteristics
- 5.5 VDD_EXT Characteristics
- 5.6 SIM_VDD Characteristics
- 5.7 VRTC Characteristics
- 5.8 Current Consumption (VBAT = 3.8V)
- 5.9 Electro-Static Discharge
- 5.10 Radio Characteristics
- 6 Manufacturing
- Appendix
Smart Machine Smart Decision
SIM900R_Hardware Design_V1.00 21 2012-07-20
z 0: minimum functionality.
z 1: full functionality (default).
z 4: flight mode (disable RF function).
Minimum functionality mode minimizes the current consumption to the lowest level. If SIM900R is set to
minimum functionality by “AT+CFUN=0”, the RF function and SIM card function will be disabled. In this case,
the serial port is still accessible, but all AT commands correlative with RF function and SIM card function will not
be accessible.
For detailed information about the AT Command “AT+CFUN=<fun>”, please refer to document [1].
Table 5: The Current consumption of Minimum Functionality Mode
<fun> Current consumption(uA) (sleep mode)
0 651
1 1000
4 715
4.3.2 Sleep Mode 1 (AT+CSCLK=1)
User can control SIM900R module to enter or exit the sleep mode 1 (AT+CSCLK=1) by DTR signal. When DTR
is in high level and without interrupt (on air and hardware such as GPIO interrupt or data in serial port), SIM900R
will enter sleep mode 1 automatically. In this mode, SIM900R can still receive paging or SMS from network but
the serial port is not accessible.
Note: For SIM900R, it requests to set AT command “AT+CSCLK=1” and ensure DTR at high level to enable the sleep mode 1;
the default value is 0, which can not make the module to enter sleep mode. For more details please refer to document [1].
4.3.3 Wake Up SIM900R from Sleep Mode 1 (AT+CSCLK=1)
When SIM900R is in sleep mode 1 (AT+CSCLK=1), the following methods can wake up the module:
z Pull down DTR pin.
The serial port will be active after DTR pin is pulled to low level for about 50ms.
z Receive a voice or data call from network.
z Receive a SMS from network.
4.3.4 Sleep Mode 2 (AT+CSCLK=2)
In this mode, SIM900R will continuously monitor the serial port data signal. When there is no data transfer over 5
seconds on the RXD signal and there is no on air and hardware interrupts (such as GPIO interrupt), SIM900R will
enter sleep mode 2 automatically. In this mode, SIM900R can still receive paging or SMS from network but the
serial port is not accessible.
Note: For SIM900R, It is requested to set AT command “AT+CSCLK=2” to enable the sleep mode 2; the default value is 0, which
can not make the module to enter sleep mode. For more details please refer to document [1].