User's Manual

M95 Hardware Design
M95_HD_V1.0 - 31 -
VDD_EXT
（OUTPUT）
V
IL
<0.1*VBAT
VBAT
PWRKEY
(INPUT)
EMERG_OFF
（INPUT）
54ms
250ms
STATUS
（OUTPUT）
800ms
1
>1s
V
IH
> 0.1*VBAT
Figure 8: Timing of turning on system
① Make sure that VBAT is stable before pulling down PWRKEY pin. The time between them
is recommended 30ms.
Note: Customer can monitor the voltage level of the STATUS pin to judge whether the module is
power-on. After the STATUS pin goes to high level, PWRKEY can be released. If the STATUS
pin is ignored, pull the PWRKEY pin to low level for more than 1 second to turn on the module.
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
 Emergent power down procedure: Turn off module using command “AT+QPOWD”
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
certain time. The power-down scenarios is illustrated in Figure 9.