M50 Hardware Design
M50_HD_V2.0
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correctly synchronized after start-up. The module is recommended to set to a fixed baud rate.
After that moment, no further AT commands can be executed. The module logs off from network
and enters power down mode, and only RTC is still active. The power down mode can also be
indicated by the pin STATUS, which is a low level voltage in this mode.
3.4.2.4. Emergency shutdown using EMERG_OFF pin
The module can be shut down by driving the pin EMERG_OFF to a low level voltage over 20ms
and then releasing it. The EMERG_OFF line can be driven by an open-drain/collector driver or a
button. The circuit is illustrated as the following figures.
Emergency
shutdown pulse
EMERG_OFF
4.7K
47K
Figure 10:
Reference circuit for EMERG_OFF by using driving circuit
S2
EMERG_OFF
TVS2
Close to S2
Figure 11:
Reference circuit for EMERG_OFF by using button
3.4.3. Restart
Customer’s application can restart the module by driving the PWRKEY to a low level voltage for
a certain time, which is similar to the way of turning on module. Before restarting the module, at
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