Product manual
XStream‐PKG‐R™RS‐232/485RFModem–ProductManualv4.2B
©2005MaxStream,Inc.Confidential&Proprietary 32
SM (Sleep Mode) Command
<Sleep Mode (Low Power)> SM Command is
used to adjust Sleep Mode settings. By default,
Sleep Mode is disabled and the modem remains
continually active. SM Command allows the
modem to run in a lower-power state and be
configured in one of eight settings.
Cyclic Sleep settings wake the modem after the
amount of time designated by SM Command. If
the modem detects a wake-up initializer during
the time it is awake, it will synchronize with the
transmitter and start receiving data after the
wake-up initializer runs its duration. Otherwise, it
returns to Sleep Mode and continue to cycle in
and out of inactivity until the Wake-up Initializer
is detected. If a Cyclic Sleep setting is chosen,
the ST, LH and HT parameters must also be set
as described in the “Sleep Mode” section of this
manual.
Pin Sleep (SM = 1)
Pin Sleep requires the least amount of power. In
order to achieve this state, DI3 (SLEEP) pin must
be asserted (high). The modem remains in Pin
Sleep until the DI3 pin is de-asserted.
After enabling Pin Sleep, the SLEEP pin controls
whether the XStream Modem is active or in Sleep
Mode. When DI3 is de-asserted (low), the modem is fully operational. When DI3 is asserted
(high), the modem transitions to Sleep Mode and remains in its lowest power-consuming state
until the DI3 (SLEEP) pin is de-asserted. DI3 is only active if the modem is setup to operate in
this mode; otherwise the pin is ignored.
AT Command: ATSM
Binary Command: 0x01
Parameter Range: 0 – 8
Parameter
Value
Configuration
0 Disabled
1 Pin Sleep
2 Serial Port Sleep
3
Cyclic 0.5 second sleep
(Modem wakes every 0.5
seconds)
4 Cyclic 1.0 second sleep
5 Cyclic 2.0 second sleep
6 Cyclic 4.0 second sleep
7 Cyclic 8.0 second sleep
8 Cyclic 16.0 second sleep
Default Parameter Value: 0
Number of bytes returned: 1
Related Commands:
For Pin Sleep – PC (Power-up Mode), PW (Pin
Wake-up)
For Serial Port Sleep – ST (Time before Sleep)
For Cyclic Sleep – ST (Time before Sleep), LH
(Wake-up Initializer Timer), HT (Time Before
Wake-up Initializer), PW (Pin Wake-up)
Once in Pin Sleep Mode, DO2 (
) is de-asserted (high), indicating that data should not be sent
to the modem. The PWR pin is also de-asserted (low) when the modem is in Pin Sleep Mode.
Note: The module will complete a transmission or reception before activating Pin Sleep.
Serial Port Sleep (SM = 2)
Serial Port Sleep is a Sleep Mode in which the XStream Modem runs in a low power state until
serial data is detected on the DI pin.
When Serial Port Sleep is enabled, the modem goes into Sleep Mode after a user-defined period
of inactivity (no transmitting or receiving of data). This period of time is determined by ST (Time
before Sleep) Command. Once a character is received through the DI pin, the modem returns to
Idle Mode and is fully operational.
Cyclic Sleep (SM = 3-8)
Cyclic Sleep is the Sleep Mode in which the XStream Modem enters into a low-power state and
awakens periodically to determine if any transmissions are being sent.
When Cyclic Sleep settings are enabled, the XStream Modem goes into Sleep Mode after a user-
defined period of inactivity (no transmission or reception on the RF channel). The user-defined
period is determined by ST (Time before Sleep) Command.
While the modem is in Cyclic Sleep Mode, DO2 (
) is de-asserted (high) to indicate that data
should not be sent to the modem during this time. When the modem awakens to listen for data,
DO2 is asserted and any data received on the DI Pin is transmitted. The PWR pin is also de-
asserted (low) when the modem is in Cyclic Sleep Mode.