Antenna Detection; Gprs Detection; Transmission Indicator; General Purpose I/O - Motorola G24 Developer's Manual

Chapter 2: Hardware Interface Description

Antenna Detection

The G24 incorporates an internal antenna detection circuit, which senses the physical connection
and removal of an antenna or antenna circuit on the G24 antenna connector. The antenna
detection state is reported to the application through the ANT_DET output signal, and may also
be queried by the ATS97 command.
The detection circuit senses DC resistance to ground on the G24 antenna connector.
A DC resistance below 100kÙ (+10%) is defined as a valid antenna connection, and the
ANT_DET output signal is set high.
A DC resistance above 100kÙ (+10%) is defined as an antenna disconnection, and the ANT_DET
output is set low.

GPRS Detection

The GPRS output signal indicates the network GPRS connection status. When G24 is connected
to a GPRS network, this signal is enabled. When G24 is not connected to the GPRS network this
signal is disabled.

Transmission Indicator

The TXEN_N output signal indicates when G24 is transmitting over the GSM network. This
signal follows the G24 GSM transmit bursts. This signal is set low during transmission burst, and
set high when no transmission is in progress.
Figure 2-28 shows the TXEN_N operation.
Figure 2-28: TXEN_N Operation

General Purpose I/O

The G24 incorporates 8 general purpose IO signals for the user application. Each GPIO signal
may be configured and controlled by AT command. These signals may be used to control or set
external application circuits, or to receive indications from the external application.
January 1, 2006 Module Hardware Description 47