USGlobalsat EM-318-01 - Manual (Page 5)

EM-318-01
Specifications are subject to be changed without notice.
Page 5 of 16
Version 1.2.2
„ 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 power supply, the GPS module/engine board will execute a cold star upon
each power-up. To achieve the faster start-ups a backup must be connected to this
pin (battery or Gold /Super capacitor). The voltage should be between 2.0v and 5.0v.
( NOTE : The VBAT pin must be kept “HIGH” for in order for the GPS board/module to
function if no backup power is going to be used. From the VCC, connect a 470 Ohm ¼
Watt resistor in series with a 3.2v Zener diode to Ground. Connect the VBAT pin to the
Zener’s cathode to pull the input “HIGH”.)
9 NRESET Reset Input (Active Low)
10 NC Not connect