User's Manual

SARA-R4 series - System Integration Manual
UBX-16029218 - R03 System description
Page 28 of 94
1.12.6 HTTP
SARA-R4 series modules provide the embedded Hyper-Text Transfer Protocol (HTTP) services via AT commands
for sending requests to a remote HTTP server, receiving the server response and transparently storing it in the
module’s Flash File System (FFS).
For more details about embedded HTTP functionalities see the SARA-R4 series AT Commands Manual [2].
1.12.7 Firmware update Over AT (FOAT)
This feature allows upgrading of the module firmware over the AT interface, using AT commands.
The +UFWUPD AT command enables a code download to the device from the host via the Xmodem protocol.
The +UFWINSTALL AT command then triggers a reboot, and upon reboot initiates a firmware installation on the
device via a special boot loader on the module. The bootloader first authenticates the downloaded image, then
installs it, and then reboots the module.
Firmware authenticity verification is performed via a security signature. The firmware is then installed,
overwriting the current version. In case of power loss during this phase, the boot loader detects a fault at the
next wake-up, and restarts the firmware installation. After completing the upgrade, the module is reset again
and wakes-up in normal boot.
For more details about Firmware update Over AT procedure, see the SARA-R4 series AT Commands Manual [2],
+UFWUPD AT command.
1.12.8 Firmware update Over The Air (FOTA)
This feature allows upgrading the module firmware over the air interface.
For more details about Firmware update Over The Air procedure see SARA-R4 series AT Commands Manual [2],
+UFWINSTALL AT command.
1.12.9 Power saving
The power saving configuration is by default disabled, but it can be enabled using the AT+CPSMS command (for
the complete description of the AT+CPSMS command, see the SARA-R4 series AT Commands Manual [2]).
When power saving is enabled, the module automatically enters the low power deep sleep mode whenever
possible, reducing current consumption (see section 1.5.1.3 and SARA-R4 series Data Sheet [1]).
For the definition and the description of SARA-R4 series modules operating modes, including the events forcing
transitions between the different operating modes, see the section 1.4.
1.12.9.1 Functionality
The SARA-R4 series modules achieve the low power deep sleep mode by powering down all the Hardware
components with the exception of the 32 kHz reference internally generated.
From the host application point of view, the USB/UART ports will not be available during low power deep
sleep mode, as the SARA-R4 module will act as if the SARA-R4 module is in Power-Off mode.
1.12.9.2 Timers and Network Interaction
The SARA-R4 series modules goes in low power deep sleep mode entering in the Power Saving Mode (PSM)
defined in 3GPP Release 13.
Two timers have been specified on the PSM Signaling: the “Periodic Update Timer” and “Active Timer”.
The “Active Timer” is the time defined by the network where the SARA-R4 series module will keep listening for
any active operation, during this time the SARA-R4 series module is in Active mode.