Technical information

Chapter 2: Hardware Interface Description
November 15, 2008 G24-L Module Hardware Description 19
Temporary Termination of Low Power Mode
Temporary termination of low power mode occurs when G24-L switches from Sleep mode to Idle
mode for a defined period, and then returns automatically to Sleep mode.
Low power mode may be terminated temporarily by several sources, some of which are user
initiated and others are initiated by the system.
Using the WKUPI_N signal
The WKUPI_N signal is an active low input, that is set high by default. By asserting this signal
low the application can wake-up G24-L from low power mode and switch to Idle mode.
G24-L will remain in Idle mode, awake and fully active, as long as WKUPI_N signal remains
low. When this signal is disabled and set high again, G24-L will return to Sleep mode
automatically, according to the ATS24 settings (see Figure 2-9).
Figure 2-9: WKUPI_N Signal Operation
The WKUPI_N signal is the recommended method to temporarily wake-up G24-L from low
power mode. It provides the application full control of the G24-L operating mode and guarantees
that data on the serial interface will not be lost or misinterpreted.
The WKUPI_N signal must be used to wake up G24-L from low power mode if the serial
interface has been disabled by the AT+MSCTS command.
Incoming Network Data
During low power mode, G24-L continues monitoring the GSM network for any incoming data,
message or voice calls.
When G24-L receives an indication from the network that an incoming voice call, message or
data is available, it automatically wakes up from low power mode to alert the application. When
G24-L has completed to process all the tasks related to the incoming data, it will automatically
return to low power mode according to the ATS24 settings.
Depending on the type of network indication and the application settings, G24-L may operate in
several methods, which are configurable by AT commands, to alert the application of the
incoming data:
• Enable the WKUPO_N signal to wake-up the application from low power.
• Send data to the application over the serial interface.
• Enable the serial interface's Ring Indicator (RI_N) signal.