RoyalTek REV-2000 User Manual

Page 26

RoyalTek GPS Receiver REB-2000/REB-12R REV-2000 Operational Manual

18 GND

G Ground

TIMEMARK

1PPS Time Mark
Output.

Voh

≥

VCC-0.4V, Vo1

≤

0.4V, Ioh = 4mA

Io1 = 4mA
Pulse duration 100ms. Time reference is at
the pulse negative edge. Measurements are
aligned to GPS second,

1 microsecond.

20 RESERVED

- Reserved

VCC_5 DC Power Input

This is the main power supply for the GPS

Engine board. Use a regulated 5V supply (

5%) capable of supplying 180mA.

VANT

DC voltage for an active antenna. This

voltage is not required for operation with a

passive antenna.

VCC_3 DC Power Input

RoyalTek also provides the 3.3 V version

GPS receiver. This is the main power supply

for the Engine board. Use a regulated 3.3V

supply (

5%).

GND

GND provides the ground for the Engine

board. Connect all grounds.

Serial Data:RXA, RXB, TXA, and TXB

The GPS Engine board supports two full

duplicated serial channels. All four

connections are at TTL levels, and all

support variable baud rates. A TTL to RS232

conversion is necessary to directly

communicate with a PC serial port.

RXA

This is the main receiving channel and is

used to receive software commands to the

Engine board from user written software.

RXB

This is the auxiliary receive channel and is

used to input differential corrections to the

Engine board to DGPS navigation.

TXA

This is the main transmit channel and is used

to output navigation and measurement data

to user written software.

TXB

Reserved.

RESET

This pin provides an active-low reset input to

the Engine board. It causes the board to reset

and start searching for satellites. PB Reset is

an optional input and, if not used, should be

tied high.

TIMEMARK

This pin provides one pulse per second output from

the engine board which is synchronized to within one

microsecond of GPS time. The output is a TTL

negative level signal with negative logic.

VBAT

This is the battery backup supply that

powers the SRAM and RTC when main

power is removed. Typical current draw is 10

uA. Without an external backup battery or on

board battery, engine board will execute a

cold start after every turn on. To achieve the

faster start-up offered by a hot or warm start,

either a backup battery must be connected

or battery installed on board.