ML8011 GSM GPRS Modem User’s Manual
Page 10
Before the completion of the power-down procedure the module sends out the result code shown
below:
NORMAL POWER DOWN
After this moment, no further AT command can be executed, and then the module enters the
POWER DOWN mode, The POWER DOWN mode can also be indicated by STATUS pin,
which is a low level voltage in this mode.
3.4.4 Over-voltage or under-voltage automatic shutdown
The module will constantly monitor the voltage applied on the VBAT, if the voltage
≤
3.5V, the
following URC will be presented:
UNDER_VOLTAGE WARNNING
If the voltage
≥
4.5V, the following URC will be presented:
OVER_VOLTAGE WARNNING
The uncritical voltage range is 3.6V to 4.6V. If the voltage > 4.6V or <3.3V, the module would
automatically shut down itself.
If the voltage <3.3V, the following URC will be presented:
UNDER_VOLTAGE POWER DOWN
If the voltage >4.6V, the following URC will be presented:
OVER_VOLTAGE POWER DOWN
After this moment, no further AT command can be executed, the module logoff from network
and enters POWER DOWN mode, The POWER DOWN mode can also be indicated by the pin
STATUS, which is a low level voltage in this mode.
3.4.5 Restart module using the PWRKEY pin
Customer
’
s application can restart the module by driving the PWRKEY to a high level voltage
for certain time, which is similar to the way to turn on module. Before restarting the module, at
least
500msshould be delayed after detecting the low level of STATUS. The restart scenario is
illustrated as the following figure 5
