User's Manual

RFD900x User Manual V2.0
www.rfdesign.com.au
8
8/1/2019
4 Pin signals and layout
Pin #
Name
Direction
Description
Max Voltage
1
GND
-
Ground
0V
2
GND
-
Ground
0V
3
CTS
Either
Clear to send
3.3V
4
Vcc
-
Power supply
5V
5
Vusb
-
Power supply from USB
5V
6
Vusb
-
Power supply from USB
5V
7
RX
Input
UART Data In
3.3V
8
GPIO5/P3.4
Either
Digital I/O
3.3V
9
TX
Output
UART Data Out
3.3V
10
GPIO4/P3.3
Either
Digital I/O
3.3V
11
RTS
Either
Request to send
3.3V
12
GPIO3/P1.3
Either
Digital I/O
3.3V
13
GPIO0/P1.0
Either
Digital I/O
3.3V
14
GPIO2/P1.2
Either
Digital I/O
3.3V
15
GPIO1/P1.1
Either
Digital I/O, PPM I/O
3.3V
16
GND
-
Ground
0V
Figure 5-1: Physical pin layout of the RFD900x Radio Modem
GPIO pins will configure for 40kOhm pull down or pull up based on setting as input or output. They
can sink or source approximately 5 mA each.