User's Manual

Confidential
INTERFACE DESCRIPT
19(31)
Document number Revision
1/155 19-KRD 104 1025 Uen PA4
5 Electrical Interface
This section describes each signal line of the electrical interface between the EDGE
modem and the host application. A summary of the function of each signal is provided,
together with any additional relevant information.
Signals are described from the perspective of the EDGE modem and Daughter Card
circuitry. Consequently signals described as input are inputs to the modem, driven by the
host [hostmodem]. Likewise, signals described as output are driven by the modem in to
the host [modemhost]. Bi-directional signal flow (I/O) is indicated by a double-headed
arrow [modemhost]. In some instances the [daughter card] will be identified if the
modem circuitry is not directly involved, or where additional interface circuitry resides
between the host and the modem.
Signals which are pulled internally are identified in parentheses beside the signal name as
either (PU)=Pulled Up or (PD)=Pulled Down. Signals with no designation are not pulled
either way.
5.1 Power Interfaces
This section describes the power, ground, and other signals that control or indicate power
states.
VIN
3V3
VREF
GND