User's Manual

XTend™RFModule‐ProductManual
©2013DigiInternatonal,Inc. 16
In order to enter Sleep Mode, one of the following conditions must be met (in addition to the
module having a non-zero SM parameter value):
When in Sleep Mode, the module will not transmit or receive data until the module first transitions
to Idle Mode. All Sleep Modes are enabled and disabled using SM Command. Transitions into and
out of Sleep Modes are triggered by various mechanisms as shown in the table below.
The SM (Sleep Mode) command is central to setting all Sleep Mode configurations. By default,
Sleep Modes are disabled (SM = 0) and the module remains in Idle/Receive Mode. When in this
state, the module remains constantly ready to respond to serial or RF activity.
Refer to the ‘Hardware Sleep’ section of the ‘Shutdown Mode’ section [previous page] to enable the
module's lowest power-consuming state (5 µA typical power-down current).
Pin Sleep (SM = 1)
• Pin/Host-controlled
• Typical power-down current: < 162 A
This mode is voltage level activated. When the SLEEP pin is asserted, the module will finish any
transmitting or receiving activity; enter Idle Mode; then enter a state of sleep. When in Pin Sleep
Mode, the module will not respond to serial or RF activity.
After enabling Pin Sleep, the SLEEP pin controls whether the module is active or sleeping. When
SLEEP is de-asserted, the module is fully operational. When SLEEP is asserted, the module
transitions to Sleep Mode and remains in its lowest power-consuming state until the pin is de-
asserted. This pin is only active if the module is setup to operate in this mode; otherwise the pin is
ignored.
Once in Pin Sleep, CTS
(GPO1) is de-asserted (high), indicating that data should not be sent to the
module. The PWR pin is also de-asserted (low) when the module is in Pin Sleep Mode.
Note: The module will complete a transmission or reception before activating Pin Sleep.
Serial Port Sleep (SM = 2)
• Wake on serial port activity
• Typical power-down current: < 10 mA
Serial Port Sleep is a Sleep Mode in which the module runs in a low power state until serial data is
detected on the DI pin.
1. The module is idle (no data transmission or reception) for the amount of time defined by
the ST (Time before Sleep) parameter. [NOTE: ST is only active when SM = 4-5.]
2. SLEEP (pin 8) is asserted (only for the ‘Pin Sleep’ option).
Table2‐01. SummaryofSleepModeConfigurations
Sleep Mode
(Setting)
Transition into
Sleep Mode
Transition out of Sleep
Mode (wake)
Related
Commands
Power
Consumption
Pin Sleep
(SM = 1)
Assert (high) SLEEP pin - A micro
controller can shut down and wake
modules via the SLEEP pin.
Note: The module will complete a
transmission or reception before
activating Pin Sleep.
De-assert (low) SLEEP pin (SM) < 162A
Serial Port Sleep
(SM = 2)
Automatic transition to Sleep Mode
occurs after a user-defined period of
inactivity (no transmitting or receiving of
data).
Period of inactivity is defined by the ST
(Time before Sleep) Command.
When a serial byte is received on
the DI pin
(SM), ST < 10 mA
Cyclic Sleep
(SM = 4 - 8)
RF module transitions in and out of Sleep Mode in cycles (user-selectable
wake-up interval of time is set using the SM command). The cyclic sleep
interval of time must be shorter than the interval of time that is defined by the
LH (Wake-up Initializer TImer) command.
Note: The module can be forced into Idle Mode using the SLEEP pin if the PW
(Pin Wake-up) command is issued.
(SM), ST, HT,
LH, PW
< 1.6 mA
when sleeping
(SM=4, 1 sec.,
@120K baud)