ET-318
Specifications are subject to be changed without notice.
Page 6 of 16
Version 1.3.1
GPIO Functions
Several I/Os are connected to the digital interface connector for custom applications.
Application Circuit
R46
560R
1
2
C1
1U
1
2
TXA
RXB
RESET
BATTERY
GPIO15
50 ohm microstrip line
GPIO13
RXA
R5
SAW FILTER
1
2
U1
GPS
6
5
4
3
2
1
7
8
9
10
11
12
13
14
15
17
16
VBAT
VCC_IN
NRESET
GND
RF_IN
GND
RXB
TXB
GND
BOOTSEL
TXA
RXA
GPIO1
GPIO14
TIMEMARK
GPIO15
GPIO13
GPIO1
3.3V
GPIO14
Antenna
1
.
RB715F
3
1
2
BOOTSEL
TXB
C2
0.1U
1
2
option
VCC_RF
TIMEMARK
LNA
2
1
.
.
Recommended Layout PAD