Serial Interface During Low Power Mode; Terminating Low Power Mode - Motorola G24 Developer's Manual

Low Power Mode

Serial Interface During Low Power Mode

The G24 wakes up periodically from low power mode to page the GSM network for any
incoming calls or data. After this short paging is completed, G24 returns to low power mode.
During this short awake period, the serial interfaces are enabled and communications with the
module is possible.
The CTS_N signal is alternately enabled and disabled synchronously with the network paging
cycle. CTS_N is enabled whenever G24 awakes to page the network. This indicates the G24
serial interfaces are active (see
Figure 2-9: CTS Signal During Sleep Mode
The periodical enabling and disabling of the CTS_N signal during low power mode can be
controlled by the AT+MSCTS command.
Setting AT+MSCTS=1 permanently disables the serial interface during low power mode, even
during a network page by G24. The CTS_N signal is disabled, and therefore the serial interfaces
are blocked.

Terminating Low Power Mode

Terminating the low power mode, or wake-up, is defined as the transition of the G24 operating
state from Sleep mode to Idle mode. There are several ways to wake-up G24 from low power
mode as described below.
Important:
20
Figure 2-9).
During power saving mode the G24 internal clocks and circuits are disabled, in
order to minimize power consumption. When terminating the power saving mode,
and switching to Idle mode, G24 requires a minimal delay time to reactivate and
stabilize its internal circuits before it can respond to application data.
This delay is typically of 5 milliseconds, and is also indicated by the CTS_N signal
inactive (high) state. The delay guarantees that data on the serial interface is not lost
or misinterpreted.
Module Hardware Description January 1, 2006