USGlobalsat EB-5662RE - Manual (Page 9)

EB-5662RE
High Performance GPS Engine Board
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OPERATING Description
VCC
This is the main power supply to the engine
board. (3.1Vdc to 3.5Vdc)
GND
This is Ground pin for the baseband circuit.
RXD
This is the main channel for receiving
software commands from SiRFDemo
software or from your proprietary software.
TXD
This is the main transmits channel for
outputting navigation and measurement data
to user’s navigation software or user written
software. Output is TTL level, 0V ~ 2.85V.
RF_IN
This pin receives signal of GPS analog via
external active antenna. It has to be a
controlled impedance trace at 50ohm. Do not
have RF traces closed the other signal path
and routing it on the top layer. Keep the RF
traces as short as possible.
VBAT
This is the battery backup power input for the
SRAM and RTC when main power is off.
Without the external backup battery,
EB-5662RE will always execute a cold star
after turning on. To achieve the faster
start-up offered by a hot or warm start, a
battery backup must be connected. The
battery voltage should be between 2.0V and
3.5V.
VDD3V3OUT
This PIN is output voltage 3.3V. If do not use
it, Just NC.
ON_OFF
The ON_OFF pin commands the EB-5662RE
ON or OFF. There are multiple methods of
connecting this pin for different applications
in order to minimize host resource
requirements.
The ON_OFF pin is used to command the
EB-5662RE to turn on or off:
 The turn on command is a hardware
feature of the Power Control FSM based
on sensing a rising edge on the pin.
 The turn off command is a software
feature based on interrupts related to
rising and/or falling edges and/ or
sensing of pin levels. (Not currently
supported.)
The ON_OFF pin processing is carried out by
the Power Control FSM. The ON_OFF rising
edge event during low power modes is
recorded in a status register that is
subsequently read by the processor once it is
running. When the processor is running at
the time of an ON_OFF event, the processor
can poll the status or set-up an interrupt.
WAKE_UP
System power controller, when EB-5662RE
Power ON, this pin will output 1.8V
dc
.
NC
EB-5662RE reserves pin, Just NC.