GETTING STARTED
20
Dragonfly
™
Nano MTQN-MNG3-B01 Device Guide
Note:
N_RESET of the 40 pin connector is directly connected to NRST of the STM32L471QG processor. The
processor controls the PWR_ON(RADIO_ONOFF/PE_4) and RESET_N(RADIO_RESET/PF_3) pins to the radio.
Low Power Modes
NOTE for MNG3:
eDRX and PSM modes are not supported in 2G (all modes are supported using Cat M1).
To achieve lowest power consumption, we recommend powering down the radio then configuring RADIO_PWR,
VMEM_EN and BUF_EN as analog inputs with no pull resistor. The last step is to place the processor in a low power
mode of your choosing.
WARNING:
If your application is using the on board flash memory part, make sure any flash accesses are complete
before removing power or the memory may be corrupted.
Cellular Radio Low Power
Note:
Refer to the U-blox AT command guide for details on AT commands.
1.
Powering Down - See Powering Down The Cellular Radio section
2.
PSM mode- AT+CPSMS command
3.
eDRX- AT+CEDRXS command
4.
Device functionality- AT+CEDRXS command
Power to Cellular Radio
After power down, RADIO_PWR can be configured as an analog input with no pull resistor to disable the power
supply regulator that powers the radio. There is an on board resistor that sets the RADIO_PWR signal level so that
the regulator is disabled.
On Board Flash Memory
After power down, RADIO_PWR can be configured as an analog input with no pull resistor to disable the power
supply regulator that powers the radio. There is an on board resistor that sets the RADIO_PWR signal level so that
the regulator is disabled.
Level translator
BUF_EN can be configured as an analog input with no pull resistor to disable the level shifter. There is an on board
resistor that sets the BUF_EN signal level so power is removed.
STM32L471QG processor
See the STM32L471QG data sheet for low power modes.
Powering Down the Cellular Radio
CAUTION:
Failing to properly power down the cellular radio before removing power may corrupt the radio's file
system.
