User's Manual

M10 Hardware Design
M10_HD_V3.0 - 37 -
3.5.3. Wake up module from SLEEP mode
When the module is in the SLEEP mode, the following methods can wake up the module.
If the DTR Pin is pulled down to a low level, it would wake up the module from the SLEEP mode.
The serial port will be active about 20ms after DTR is changed to low level.
Receive a voice or data call from network to wake up module.
Receive an SMS from network to wake up module.
RTC alarm expired to wake up module.
Note: DTR pin should be held low level during communicating between the module and DTE.
3.6. Summary of state transitions (except SLEEP mode)
Table 8: Summary of state transition
3.7. RTC backup
The RTC (Real Time Clock) can be supplied by an external capacitor or battery (rechargeable or
non-chargeable) through the pin VRTC. A 1.5K resistor has been integrated in the module for
current limiting. A coin-cell battery or a super-cap can be used to backup power supply for RTC.
The following figures show various sample circuits for RTC backup.
Current mode Next mode
POWER DOWN Normal mode Alarm mode
POWER DOWN Use PWRKEY Turn on the module by RTC
alarm
Normal mode Use “AT+QPOWD”
command, PWRKEY
pin, or EMERG_OFF
pin
Set alarm by “AT+QALARM”,
and then turn off the module.
When the timer expires, the
module turns on automatically
and enters Alarm mode.
Alarm mode Use PWRKEY pin or
wait module turning
off automatically
Use
“AT+CFUN”
command