M20 Hardware Design
VDD_EXT
（
OUTPUT
）
V
IL
<0.2*VBAT
V
IH
> 0.6*VBAT
Pulldown > 2s
Hiz
VBAT
PWRKEY
(INPUT)
Figure 7: Timing of turn on the module
When the power-on procedure completes, the module will send out the following result code to
indicate the module is ready to operate when the baud rate of the serial port is set to fixed.
RDY
This result code does not appear when autobauding is active.
3.4.1.2 Turn on module using the RTC (Alarm mode)
Alarm mode is a power-on approach by using the RTC. The alert function of RTC can wake-up
the module while it is in power-off state. In alarm mode, the module will not register to GSM
network and the GSM protocol stack software is closed. Thus the part of AT commands related
with SIM card and the protocol stack will not be accessible, and the others can be used.
Use the “AT+QALARM” command to set the alarm time. The RTC remains the alarm time if the
module is powered off by “AT+QPOWD=1” or by PWRKEY pin. Once the alarm time is expired,
the module will go into the alarm mode. In this case, the module will send out an Unsolicited
Result Code (URC) when the baud rate of the serial port is set to fixed.
ALARM RING
RDY
This result code does not appear when autobauding is active.
During alarm mode, use “AT+CFUN” command to query the status of software protocol stack; it
M20_HD_V1.01
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Quectel
