u-blox LEXI-R422, System Integration Manual

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LEXI-R422 - System integration manual
UBX-23007449 - R02 System description Page 14 of 108
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The initial operating mode of LEXI-R422 modules is the one with VCC supply not present or below the
operating range: the modules are switched off in not-powered mode.
Once a valid VCC supply is applied to the LEXI-R422 modules, they remain switched off in the
power-off mode. Then the proper toggling of the PWR_CTRL input line is necessary to trigger the
switch-on routine of the modules that subsequently enter the active mode.
LEXI-R422 modules are ready to operate when in active mode: the available communication interfaces
are completely functional and the module can accept and respond to AT commands, entering
connected mode upon cellular RF signal reception / transmission.
The external GNSS can be concurrently enabled by the dedUGPS AT command.
LEXI-R422 modules switch from active mode to the low power idle mode whenever possible, if the low
power configuration is enabled by the dedUPSV AT command. The low power idle mode can
last for different time periods according to the spUPSV AT command setting, according to the
DRX / eDRX setting, and according to the concurrent activities executed by the module.
LEXI-R422 modules enter the User Equipment (UE) power saving mode (PSM) defined in 3GPP Rel.13
whenever possible, if PSM is enabled by the +CPSMS / +UCPSMS AT commands, and according to the
+UMNOPROF AT command settings. The PSM can last for different time periods according to the
T3412 periodic TAU timer set by the network. Then, the modules enter the ultra-low power deep-sleep
mode whenever possible, if no other concurrent activities are executed by the module.
Modules may automatically enter the ultra-low power deep-sleep mode in-between eDRX cycles,
whenever possible, if the functionality is enabled using the +UPSMVER AT command.
Once the modules enter the ultra-low power deep-sleep mode, the available communication interfaces
are not functional: a wake-up event, consisting in proper toggling of the
PWR_CTRL input input line
or the expiration of the timer set by the network, is necessary to trigger the wake-up routine of the
modules that subsequently enter back into the active mode.
LEXI-R422 modules can be gracefully switched off by the dedCPWROFF AT command, or by
proper toggling of the
PWR_CTRL input.
Figure 2 describes the transition between the different operating modes.
Remove VCC
Switch ON:
• PWR_CTRL
Not powered
Power off
Switch OFF:
• AT+CPWROFF
•
PWR_CTRL
Apply VCC
If PSM mode is enabled (AT+CPSMS=1),
if AT inactivity timer and T3324 are expired, if no
other concurrent activity is executed
•
Upon expiration of the Periodic Update Timer
• Using PWR_CTRL pin
Incoming/outgoing data, or
other dedicated network communication
No RF Tx/Rx in progress,
communication dropped
Active Connected Deep Sleep
If low power idle mode is enabled (AT+UPSV
≠
0),
if AT inactivity timer is expired,
if there is none concurrent activity
Idle
Data received over UART (if AT+UPSV=4),
DTR assert to ON (if AT+UPSV=3),
Other concurrent activity
Figure 2: LEXI-R422 modules operating modes transitions