hardware design v1.00
Table Of Contents
- Contents
- Version History
- 1 Introduction
- 2 SIM968 Overview
- 3 Package Information
- 4 GSM Application Interface
- 4.1 GSM Power Supply
- 4.2 Power on/down Scenarios
- 4.3 Power Saving Mode
- 4.4 Charging Interface
- 4.5 RTC Backup
- 4.6 Serial Interfaces
- 4.7 Audio Interfaces
- 4.8 SIM Card Interface
- 4.9 LCD Display/SPI Interface
- 4.10 Keypad Interface
- 4.11 ADC
- 4.12 RI Behaviors
- 4.13 Network Status Indication
- 4.14 General Purpose Input/Output (GPIO)
- 4.15 External Reset
- 4.16 PWM
- 4.17 I2C Bus
- 4.18 GSM Antenna Interface
- 5 GNSS Application Interface
- 6 Electrical, Reliability and Radio Characteristics
- 6.1 Absolute Maximum Ratings
- 6.2 Recommended Operating Conditions
- 6.3 Digital Interface Characteristics
- 6.4 SIM Card Interface Characteristics
- 6.5 VDD_EXT Characteristics
- 6.6 SIM_VDD Characteristics
- 6.7 VRTC Characteristics
- 6.8 Current Consumption (VBAT = 3.8V)
- 6.9 Electro-Static Discharge
- 6.10 Radio Characteristics
- 6.11 Module label information
- Appendix
Smart Machine Smart Decision
SIM968_Hardware Design_V1.00 2013.02.25
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5 GNSS Application Interface
5.1 Power Management
5.1.1 GNSS Power Input
The GPS_VCC supply range is from 2.8V to 4.3V, and it should be able to provide sufficient current up to
100mA.
5.1.2 Starting GNSS Engine
z When GNSS power is first applied, The GNSS Engine goes into operation mode.
5.1.3 Verification of GNSS Engine Start
System activity indication depends upon the chosen serial interface:
z When it is activated, SIM968 will output messages at the selected UART speed, and message types.
5.1.4 Power Saving Modes
SIM968 supports operating modes for reduced average power consumption like sleep mode, backup mode,
periodic mode, and AlwaysLocate
TM
mode.
z Sleep mode: In this mode the receiver stays at full on power state. When this mode that can be wake up by
the host sends the command through the communication interface or external interrupt.
z Backup mode: In this mode the SIM968 must be supplied by the backup and it can help to count down the
time for backup mode. Software on host side to send the command through the communication interface
into the backup mode.
z Periodic mode: In this mode the SIM968 enters tracking and sleep modes according to the interval
configured by users in the commands.
z AlwaysLocate
TM
mode: AlwaysLocate
TM
is an intelligent controller of SIM968 periodic mode. Depending
on the environment and motion conditions, SIM968 can adaptive adjust the on/off time to achieve balance
of positioning accuracy and power consumption.
Note: the modes mentioned above are operated by PMTK commands, users can refer to document [19] for more information.
SIM968 provides very low leakage battery back up memory, which contains all the necessary GNSS information
for quick start up and a small amount of user configuration variables. It needs a 3V power supply for V_BACKUP
pin, and the stable operation region ranges from very light load to about 3mA.
5.1.5 Operating Mode
Table 19: Power supply and clock state according to operation mode