CHAPTER 3 SPECIFICATIONS AND RELATED INFORMATION
MultiConnect
®
Dragonfly
TM
MTQ-EV3 Device Guide
23
Powering Down Your Device
CAUTION:
Failing to properly power down the device before removing power may corrupt your device's file
system.
To properly power down your device, use the following sequence or pull 3G_ONOFF signal low:
1.
Issue the AT#SHDN command.
2.
Wait 30 seconds.
3.
Power off or disconnect power.
Note:
If you send AT#SHDN and do not remove power AND the 3G_ONOFF line is high, the control chip on the
device turns the radio back on after 60 seconds.
3G_ONOFF Signal
Minimum pulse is 200
μ
s up to 900 msec.
This short pulse causes an unconditional radio shutdown.
There is no controlled disconnect from the network.
The radio restarts.
The radio takes 10 seconds to recover and finish starting.
Holding 3G_ONOFF low longer than 1 second causes a controlled disconnect from the network and then
turns the radio off.
The radio stays off as long as 3G_ONOFF is held low.
Due to the network disconnect, shutoff can take up to 30 seconds.
Device Reset
Processor Models (B01)
To reset the processor, the minimum recommended reset pulse is 200
μ
s. The maximum reset pulse is less
than 1 second.
Refer to STM32F411 documentation for additional reset options available within the on-board
microcontroller.
Reset is controlled via PC13 on the on-board microcontroller.
Refer to 3G_ONOFF Signal for instructions on managing radio module reset.
No Processor Models (B02)
For the -B02 models, reset is connected to the 3G_ONOFF signal. Refer to the 3G_ONOFF topic for functionality.
Sleep Mode
Control radio sleep mode with the GPIO pin PC13 (3G_ONOFF) on the onboard processor. See also
3G_ONOFF
Signal
.
Setting PC13 to Low and holding it low turns the radio off, causing it to draw minimal power.
Setting PC13 to High resets and wakes up the device.
