Specifications

Cinterion
®
EXS62-W/EXS82-W Hardware Interface Description
3.3 Power Saving
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3.3.1.1 SLEEP Mode
SLEEP mode is a module’s low power mode when no call is in progress and there is no active
communication on any serial interface (ASC0, ASC1). During SLEEP mode, the serial interfac-
es are shut down except for RTS0 that may be used to wake up EXSx2-W from SLEEP mode
(see below). The module is in a low power consumption state depending on paging cycles
based on network defined DRX values, and possibly network negotiated eDRX (extended
DRX) as well as 3GPP PSM values - if configured.
The firmware is active to a minimum extent, and preserves the state it was in before entering
the SLEEP mode. The module stays registered to the network.
For details on the network based DRX values see Section 3.3.2.1 (GSM/(E)GPRS) and Section
3.3.3.1 (LTE M1 NB1/2). For details on the network negotiated eDRX values see Section
3.3.3.2, for network negotiated 3GPP PSM values see Section 3.3.3.3.
Note: While in eDRX SLEEP mode (or eDRX SUSPEND mode), i.e., during the low power
states reached within extended DRX paging cycles, the module may not able to react to real
time response requests at a good pace (e.g., ping requests). Thus, if an external application
needs to deal with real time responses, it is recommended to disable the use of eDRX, or to at
least reduce the default time period for the eDRX timer. In this way, the time period the module
will not react to an external request, i.e., the paging cycle length reduced by the paging time
window, i.e., PCL - PTW, can be minimized. AT+CEDRXS can be used to configure the use of
eDRX including negotiation of PCL values, whereas AT^SEDRXS does the same, but can in
addition be used to negotiate PTW values (see [1]). Default value for PCL is "1101"=2621.44
seconds, and for PTW is "0100"=12.8 seconds.
The SLEEP mode option an be enabled/disabled by AT command (see [1]: AT^SCFG param-
eter “MEopMode/PwrSave”).
RTS0 can be used to wake up EXSx2-W from SLEEP mode between paging cycles. Assertion
of RTS0 (i.e., toggle from inactive high to active low) serves as wake up event, thus allowing
an external application to almost immediately terminate power saving. After RTS0 assertion,
the CTS0 line signals module wake up, i.e., readiness of the AT command interface. It is there-
fore recommended to enable RTS/CTS flow control (default setting). Figure 39 shows the
described RTS0 wake up mechanism.
Figure 39: Wake-up via RTS0
RTS0
CTS0
TXD0
RXD0
AT command
Reply URC
RTS assertion (falling edge)
Wake up from SLEEP mode
Return to SLEEP mode
RTS back