Integration Manual

SARA-R4/N4 series - System Integration Manual
UBX-16029218 - R11 System description Page 49 of 157
PSM low power deep sleep mode
(periodic update timer)
Connected mode: Data Tx / Rx
Active mode
(active timer)
Time
Current
Figure 14: Description of the PSM timing
1.13.9.4 Timers and AT interaction
The SARA-R4/N4 series modules go into low power deep sleep mode and enter the Power Saving Mode
(PSM) only after the 6 s “AT Inactivity Timer” expires:
 If the UART interface is used, when the host application stops sending AT commands for 6 s – the “AT
Inactivity Timer” expiration – then the module enters deep sleep power saving mode according to
“Active Timer” expiration.
 If the USB interface is enabled, the module does not enter the deep sleep power saving mode.
1.13.9.5 AT commands
The module uses the +CPSMS AT command with its defined parameters to request PSM timers to the
network.
☞ See the SARA-R4/N4 series AT Commands Manual [2] for details of the +CPSMS operation and features.
1.13.9.6 Host application
The PSM low power deep sleep mode implementation allows the SARA-R4/N4 series module to help extend
the battery life of the application.
The Host Application should be aware that the SARA-R4/N4 series module is PSM-capable.
☞ The host application needs to sense the V_INT supply output of the module to get the notification
when the module has entered into PSM low power deep sleep mode.
☞ If the host application receives an event that needs to be reported by the SARA-R4/N4 series module
interrupting the PSM low power deep sleep mode, it can be done so by setting the module into Active
mode using the appropriate power-on event (see 1.6.1).
☞ From the host application point of view, the module will look as it is in Power-Off mode.