User's Manual
Table Of Contents
- Contents
- Table Index
- Figure Index
- 0. Revision history
- 1. Introduction
- 2. Product concept
- 3. Application interface
- 3.1. Pin
- 3.2. Operating modes
- 3.3. Power supply
- 3.4. Power on and down scenarios
- 3.5. Power saving
- 3.6. Summary of state transitions
- 3.7. RTC backup
- 3.8. Serial interfaces
- 3.9. Audio interfaces
- 3.10. SIM card interface
- 3.12. Behaviors of the RI
- 3.13. Network status indication
- 3.14. Operating status indication
- 4. Antenna interface
- 5. Electrical, reliability and radio characteristics
- 6. Mechanical dimensions
- 7. Storage and Manufacturing
- Appendix A: GPRS coding schemes
- Appendix B: GPRS multi-slot classes
M95 Hardware Design
M95_HD_V1.0 - 33 -
3.4.2.2. Power down the module using AT command
Customer’s application can turn off the module via AT command “AT+QPOWD=1”. This
command will let the module to log off from the network and allow the software to save important
data before completely disconnecting the power supply, thus it is a safe way.
Before the completion of the power-down procedure the module sends out the result code shown
as below:
NORMAL POWER DOWN
After that moment, no further AT commands can be executed. And then the module enters the
POWER DOWN mode, only the RTC is still active. The POWER DOWN mode can also be
indicated by STATUS pin, which is a low level voltage in this mode.
Please refer to document [1] for details about the AT command “AT+QPOWD”.
3.4.2.3. Over-voltage or under-voltage automatic shutdown
The module will constantly monitor the voltage applied on the VBAT, if the voltage is ≤ 3.5V, the
following URC will be presented:
UNDER_VOLTAGE WARNING
If the voltage is ≥ 4.5V, the following URC will be presented:
OVER_VOLTAGE WARNING
The uncritical voltage range is 3.3V to 4.6V. If the voltage is > 4.6V or <3.3V, the module would
automatically shutdown itself.
If the voltage is <3.3V, the following URC will be presented:
UNDER_VOLTAGE POWER DOWN
If the voltage is >4.6V, the following URC will be presented:
OVER_VOLTAGE POWER DOWN
Note: These result codes don’t appear when autobauding is active and DTE and DCE are not
correctly synchronized after start-up. The module is recommended to set to a fixed baud rate.
After that moment, no further AT commands can be executed. The module logs off from network
and enters POWER DOWN mode, and only RTC is still active. The POWER DOWN mode can
also be indicated by the pin STATUS, which is a low level voltage in this mode.