User`s guide

RN-WIFLYCR-UG
www.rovingnetworks.com Version 1.2r 4/30/13 page 59
Tabl e 3-9 describes the values to wake the module using individual sensor inputs.
The sensor inputs are rated 1.2-V DC, maximum. You must use a resistor divider when
driving a sensor pin from the other 3-V pins such as RX. You should use a resistor
divider network with a minimum of 24 K in series and 10 K to ground from the UART
RX or CTS pin.
An open-drain FET is an appropriate device to tie to the sensor pin as the threshold is
about 500 mV. You can use additional pull-up to 1.2-V DC if the circuit has an imped-
ance (due to leakage current) of less than 5 Mohms (500 mv/100 nA). Leave unused
sensor pins disconnected.
3.6 WAKE ON UART ACTIVITY
When the module is in sleep mode, the UART is disabled. However, the module can
wake on UART activity by connecting the sensor pins to the RX data or CTS pin (using
the appropriate divider resistors as described in “Wake on Sensor Input” on page 58).
The RN-134 and the RN-174 evaluation boards have a built in resistor divider connect-
ing SENSE0 and SENSE1 to RXD and CTS, respectively. This setup allows wake on
RX and CTS using a 3.3-V signal.
To enable wake on RXD, use the set sys trig 1 command.
TABLE 3-9: SENSOR INPUT VALUES
Wake on Sensor Input Value Command
01 set sys trigger 1
12 set sys trigger 2
24 set sys trigger 4
38 set sys trigger 8
WARNING
The voltage on any sensor input CANNOT exceed 1.2-V DC or the module will be
permanently damaged.
WARNING
Do not apply 3.3 V directly to SENSE0 and SENSE1; the voltage on any sensor input
CANNOT exceed 1.2-V DC or the module will be permanently damaged.