WCM802/900
20
JUN
2005
PAGE
9
Pin Signals
Figure
1.1.
WCM802
/
WCM900
OEM
RF
Module
Pin
Numbers
(bottom
view,
pins
protruding)
Table
1.2.
J1
Pin
Signal
Descriptions
(Low
‐
asserted
signals
distinguished
with
a
horizontal
line
over
signal
name.)
Module
Pin
Signal Name
I/O
When Active
Function
(clear-to-send) flow control – When pin is driven low,
UART host is permitted to send serial data to the module.
Refer to the Serial Communications [p9] and CS Command
[p19] sections for more information.
1
DO2 /
/
RS-485 Enable
O* low
RS-485 Enable – To configure this pin to enable RS-485 (2-
wire or 4-wire) communications, refer to the Serial
Communications [p9] and CS Command [p19] sections.
2
DI3 / SLEEP
I*
high
By default, DI3 pin is not used. To configure this pin to
support Sleep Modes, refer to the Sleep Mode [p13], SM
Command [p27] and PW Command [p24] sections.
3
DO (data out)
O*
n/a
Serial data exiting the module (to the UART host). Refer to
the Serial Communications [p9] section for more information.
4
DI (data in)
I
n/a
Serial data entering the module (from UART host). Refer to
the Serial Communications [p9] section for more information.
(request-to-send) flow control – By default, this pin is not
used. To configure this pin to regulate the flow of serial data
exiting the module, refer to the Serial Communications [p9]
and RT Command [p26] sections.
5 DI2
/
/ CMD
I**
low
CMD –Refer to Binary Commands [p15] and RT Command
[p26] sections to enable binary command programming.
6
I* low Re-boot
module.
7
DO3 / RX LED
O
high
Pin is driven high during RF data reception; otherwise, the
pin is driven low. Refer to the CD Command [p19] to enable.
low
- Pin pulses low during RF transmission.
8
/ PWR
O
high
PWR – Indicates power is on and module is not in Sleep
Mode.
9
I*** low
Pin can be used as a backup method for entering Command
Mode during power-up. Primary method is with “+++”. Refer
to the Command Mode [p14] section for more information.
10
VCC
I
-
5 VDC regulated (± 0.25)
11 GND
-
-
Ground
*
Module
has
10K
Ω
internal
pull
‐
up
resistor
**
Module
has
10K
Ω
internal
pull
‐
down
resistor
***
Module
has
100K
Ω
internal
pull
‐
up
resistor
Note: When integrating the WCM802 / WCM900 Module with a Host PC Board, all lines that are not
used should be left disconnected (floating).
Table
1.3.
J2
Pin
Signal
Descriptions
Module
Pin
Signal Name
1 reserved
2 GND
3 GND
4 GND
J2
Pins
are
used
primarily
for
mechanical
stability
and
may
be
left
disconnected.
