2 The Host Interface
2.1 SIGNALS
The connection to the RPM2A is a full duplex serial interface supporting baud rates from 600bps to
115200bps. Additional control signals are provided to assist in flow control, configuration and power
saving in the RPM2A.
side views
39 mm
33mm
23 mm
5mm
10 mm
top view
22 GND
1
2
3
4
5
6
7
8
9
RF GND
RF
21
20
19
18
Vc c
DEFAULT
RXFLOW/CTS
RXD
RF GND
RX SELECT
TX SELECT
GND
17 TXD
23 mm
16
15
14
WAKE/DTR
SETUP
TXD/AF
D3
RESET
D2
13 RXR
12 RXA
SIGNAL
10
RST
11
36.5mm
39 mm
recommended PCB
hole size: 0.9 mm
pin pitch: 2 mm
Figure 5: Physical dimensions and pinouts
Pin name Pin
Pin Function
RF signal ground
RF signal
In/Out
Description
BNC casing/coax braid connection
Antenna pin/coax core connection
RF GND
1, 3
RF
2
Input or
Output
Input
or Output
Input
or Output
Input
or Output
NC
RXSELCT
TX SELECT
TXD/AF
4
5
7
Receiver Select
Internal RF Receiver Enable to BiM2A
or RF Receiver Active Indicator
Internal RF Transmitter Enable to BiM2A
or RF Transmitter Active Indicator
Transmitted Packetised Data to BiM2A
Analogue Demodulated signal from BiM2A
Internal data line between RPM and FRPC
Internal data line between RPM and FRPC
Valid preamble indicator
Resets FRPC which also isolates BiM2A
RPM to FRPC download Request Acknowledge
Valid Data packet indicator
Transmitter Select
Transmitted Data
or demodulated signal
FRPC Data line
FRPC Data line
Preamble Detect
FRPC reset
Receive Acknowledge
Receive Request
Reset
D3
8
D2
9
NC
Output
NC
SIGNAL
RST
RXA
RXR
RESET
SETUP
10
11
12
13
14
15
NC
Output
Input
Input
Input
Input
Output
Output
Input
Input
-
Hardware reset of the RPM2A
Enter Setup
Enter RPM2A configurator after a RESET
Wakes RPM2A when low, shuts down when high
Host (DTE) to RPM2A serial transmit data
RPM2A to host (DTE) serial received data
Hardware flow control of data from host (DTE)
Force the RPM2A serial interface to 9600bps
+5VDC or +3VDC regulated supply
WAKE/DTR 16
Wake or Shutdown
Serial transmitted data
Serial Received data
Clear To Send
Force 9600bps
Vcc Supply
TXD
17
RXD
18
CTS
19
DEFAULT
VCC
20
21
GND
6, 22
Ground
Supply Ground internally connected to GND
Notes: 1. RXD/TXD lines are true data
2. Active low SETUP, DEFAULT inputs require external 10kΩ pull-up to VCC.
3. Logic levels are 5V CMOS unless 3V variant is used.
4. WAKE pin should be pulled to ground if DTE cannot provide DTR signal
5. TXSELECT, RXSELECT, SIGNAL, RXR, CTS can be connected to LEDs via 1kΩ series resistors
Radiometrix Ltd.
UHF FM Radio Packet Modem
page 4
RADIOMETRIX [ RADIOMETRIX LTD ]
