HORNER HE200WCM910 User Manual page 45

RS‐232/485 RF Modem Product Manual – MAN0782‐02
SM (Sleep Mode) Command
<Sleep Mode (Low Power)> SM Command is used
to set/read the modem's Sleep Mode settings that
configure the modem to run in states that require
minimal power consumption.
Pin Sleep (SM = 1)
Next to Shutdown Mode, Pin Sleep requires the
least amount of power. In order to achieve this
state, SLEEP must be asserted (high). The
modem remains in Pin Sleep until the SLEEP pin
is de-asserted.
After enabling Pin Sleep (SM=1), GPI2 controls
whether the RS-232/485 Modem is active or in
Sleep Mode. When GPI2 is de-asserted (low), the
modem is fully operational. When GPI2 is
asserted (high), the modem transitions to Sleep
Mode and remains in its lowest power-consuming
state until the Sleep pin is de-asserted. GPI2 is
only active if the modem is setup to operate in
this mode; otherwise the pin is ignored.
Once in Pin Sleep Mode, GP01 (
asserted (high), indicating that data should not
be sent to the modem. PWR is also de-asserted
(low) when the modem is in Pin Sleep Mode.
Serial Port Sleep (SM = 2)
Serial Port Sleep is a Sleep Mode in which the RS-
232/485 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 = 4-8)
Cyclic Sleep is the Sleep Mode in which the RS-232/485 Modem enters into a low-power state
and awakens periodically to determine if any transmissions are being sent. Cyclic sleep settings
wake the modem after the amount of time designated by the associated SM parameter values. If
the modem detects a wake-up initializer during the time it is awake, the modem synchronizes
with the transmitting modem and starts receiving data after the wake-up initializer runs its
duration. Otherwise, the modem returns to Sleep Mode and continues to cycle in and out of
activity until a 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.
When Cyclic Sleep settings are enabled, the RS-232/485 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, GP01 (
should not be sent to the modem during this time. When the modem awakens to listen for data,
GP01 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.
AT Command: ATSM
Binary Command: 0x01
Parameter Range: 0 – 8
Parameter
Default Parameter Value: 0
Number of bytes returned: 1
Related Commands:
Pin Sleep – PC (Power-up Mode), PW (Pin
) is de-
Wake-up)
Serial Port Sleep – ST (Time before Sleep)
Cyclic Sleep – ST (Time before Sleep), LH
(Wake-up Initializer Timer), HT (Time Before
Wake-up Initializer), PW (Pin Wake-up)
) is de-asserted (high) to indicate that data
Configuration
Value
0 Disabled
1 Pin Sleep
2 Serial Port Sleep
3 reserved
Cyclic 1.0 second sleep
4 (Modem wakes every 1.0
second)
5 Cyclic 2.0 second sleep
6 Cyclic 4.0 second sleep
7 Cyclic 8.0 second sleep
8 Cyclic 16.0 second sleep
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