User's Manual Part 1

28 Specifications Expedite G301 OEM Module Specifications
Revision 1.8 P/N 90023363
There is also a WAKE_UP signal which is used to wake the modem up from a sleep state.
This signal is rising edge interrupt triggered. The host can determine if the modem is in
sleep mode by polling the SM_IND signal which will be asserted high when the modem is
asleep.
The MDM_RDY signal is asserted high when the modem is capable of communicating
with the host. MDM_RDY should always be used by the host to enable buffers that are
used for inputs to the modem. In the event that MDM_RDY is deasserted, the modem is
not capable of sending or receiving data on either of it’s serial ports.
A description of each power on mode is given below.
Pulsed Power-On
With the PUL_PWREN pin in a high state, the modem must be powered on by providing
an active high pulse of minimum 600mS to the PWR_ON pin. Once MDM_RDY goes high,
PWR_ON can drop and the modem will stay on.
This mode of operation will allow the modem to be shut down by a software AT command
(ATH4). When the command is issued, the processor will deregister from the network and
perform any power down activities required and then will drive MDM_RDY low before
powering off.
Solid Power-On
With the PUL_PWREN pin in a low state, and the PWR_ON signal is driven high, the
modem will turn on. The PWR_ON signal must remain high to keep the modem on.
This mode of operation will not permit a software shutdown.
If the modem is to be operated with this method, care must be taken to perform the
necessary network activities (eg. De-registration) before shutting the modem off.
Serial Ports
The Expedite module has two serial ports (primary and secondary) used to communicate
with the host and other peripheral devices. The primary serial port consists of the DTR,
DSR, RTS, CTS, DTM, and DFM signals. It operates at baud rates of 9600 to 115200, has
8 data bits, no parity bit, and 1 stop bit per character. The inputs (DTR, RTS, and DTM)
are buffered from the host allowing for a voltage to be present on these lines even when
the modem is off. Note that all other inputs to the modem, with the exception of ADC_IN
need to be externally buffered so as not to present a voltage when the modem is off.
When the modem goes to sleep, typically on a sleep schedule, it will deassert it’s CTS
line to indicate to the host that it cannot accept characters. Hardware flow control support
is obligatory so that the host does not accidentally send characters while the modem is
asleep. The sleep schedule will be determined by each network carrier, but typically the
modem will not sleep for more than 2 seconds at a time.
All network traffic will travel on the primary serial port.
GPIO
The Expedite provides 6 separate GPIO’s that can be individually programmed via
software AT commands.