Hardware Design V1.01(091226)
Table Of Contents
- Contents
- Version history
- 1 Introduction
- 2 SIM900 Overview
- 3 Application Interface
- 3.1 SIM900 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 SIM Card Interface
- 3.11 LCD Display Interface
- 3.12 Keypad Interface
- 3.13 ADC
- 3.14 Behaviors of the RI
- 3.15 Network Status Indication
- 3.16 General Purpose Input Output (GPIO)
- 3.17 External Reset
- 3.18 PWM
- 3.19 I2C Bus
- 4 Antenna Interface
- 5 Electrical, Reliability and Radio Characteristics
- 6 Mechanics
SIM900 Hardware Design
PWRKEY_OUT
PWRKEY
MODULE
SIM900
Figure 10: Turn on SIM900 using button
The power on scenarios illustrates as following figure.
Figure 11: Timing of turn on system using PWRKEY and PWRKEY_OUT
3.4.2 Turn Off SIM900
Following procedure can be used to turn off the SIM900:
z Normal power down procedure: Turn off SIM900 using the PWRKEY pin
z Normal power down procedure: Turn off SIM900 using AT command
z Over-voltage or under-voltage automatic shutdown: Take effect if over-voltage or under-voltage is detected
z Over-temperature or under-temperature automatic shutdown: Take effect if over-temperature or
under-temperature is detected
SIM900_HD_V1.01 26.12.2009
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