USGlobalsat EM-318-02 - Manual (Page 5)

EM-318-02
Specifications are subject to be changed without notice.
Page 5 of 16
Version 1.2.1
„ Pin Assignment
Pin # Name Description
1 VCC_IN DC Supply Voltage input
2 GND Analog Ground
3 1PPS One Pulse per second output synchronized to GPS time. Not available in
trickle mode.
4 BOOTSEL Boot mode – set high to program flash
5 TXA Serial output for channel
6 RXA Serial input for channel
7 GPIO1 GPS Fix status output
8 VBAT Backup voltage supply This is the battery backup input that powers the SRAM and
RTC when main power is removed. Typical current draw is 15uA. Without an external
backup battery, the module/engine board will execute a cold star after every turn 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 5.0v. ( NOTE : This pin
must be kept “HIGH” for operation. From Vcc connect a 470 Ohm resistor in series
with a 3.2v Zener diode to Ground. Then, connect the VBAT input to Zener’s cathode
to pull the input “HIGH”.)
9 NRESET Reset Input (Active Low)
10 NC Not connect