User's Manual

M50 Hardware Design
M50_HD_V2.0 - 34 -
3.4.2. Power down
The following procedures can be used to turn off the module:
 Normal power down procedure: Turn off module using the PWRKEY pin

Normal power down procedure: Turn off module using command “AT+QPOWD”
 Over-voltage or under-voltage automatic shutdown: Take effect when over-voltage or
under-voltage is detected
 Emergent power down procedure: Turn off module using the EMERG_OFF pin
3.4.2.1. Power down module using the PWRKEY pin
Customer’s application can turn off the module by driving the PWRKEY to a low level voltage for
a certain time. The power down scenario is illustrated in Figure 9.
VBAT
PWRKEY
(INPUT)
STATUS
(OUTPUT)
EMERG_OFF
(INPUT)
Logout net about 2s to 12s
0.6s<Pulldown<1s
>160us
Figure 9: Timing of turning off the module
The power down procedure causes the module to log off from the network and allows the
firmware 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
below:
NORMAL POWER DOWN
Note: This result code does not appear when autobauding is active and DTE and DCE are not
correctly synchronized after start-up. The module is recommended to set a fixed baud rate.
After that moment, no further AT commands can be executed. Then the module enters the power
down mode, only the RTC is still active. The power down mode can also be indicated by the
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