GSM/GPRS Module
M85 Hardware Design
M85_Hardware_Design Confidential / Released 29 / 92
1. Make sure that VBAT is stable before pulling down PWRKEY pin. The time of T
1
is recommended
30ms.
2.
EMERG_OFF should be floated when it is unused
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
It is a safe way to 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)
VDD_EXT
(OUTPUT)
EMERG_OFF
(INPUT)
Logout net about 12s
0.6s<Pulldown<1
s
Figure 9: Turn-off timing
NOTES
Quectel
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