GSM/GPRS Module Series
M85 Hardware Design
M85_Hardware_Design Confidential / Released 30 / 88
The normal input voltage range is from 3.3V to 4.6V. If the voltage is >4.6V or <3.3V, the module would
automatically shut down 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
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.
1. These unsolicited result codes do not 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.
2. Over-voltage warning and shutdown function is disabled by default.
3.4.2.4. Emergency Shutdown Using EMERG_OFF Pin
The module can be shut down by driving the pin EMERG_OFF to a low level voltage over 40ms and then
releasing it. The EMERG_OFF line can be driven by an open-drain/collector driver or a button. The circuit
is illustrated as the following figures.
Emergency
shutdown pulse
EMERG_OFF
4.7K
47K
Figure 10: An Open-collector Driver for EMERG_OFF
NOTES