Modes of operation
9XTend-PKG-R RS-232/485 RF Modem User Guide
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The SM (Sleep Mode) command is central to setting all Sleep Mode configurations. By default, Sleep Modes are
disabled (SM = 0) and the modem remains in Idle/Receive Mode. When in this state, the modem remains constantly
ready to respond to serial or RF activity.
Pin Sleep (SM = 1)
•
Pin/Host-controlled
This mode is voltage level activated. When the GPI2 pin is asserted, the modem will finish any transmitting or
receiving activity; enter Idle Mode; then enter a state of sleep. When in Pin Sleep Mode, the modem will not respond to
serial or RF activity.
After enabling Pin Sleep, the GPI2 pin controls whether the modem is active or sleeping. When GPI2 is de-asserted, the
modem is fully operational. When GPI2 is asserted, the modem 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 modem 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 modem. The PWR
pin is also de-asserted (low) when the modem is in Pin Sleep Mode.
Note: The modem will complete a transmission or reception before activating Pin Sleep.
Serial Port Sleep (SM = 2)
•
Wake on serial port activity
Serial Port Sleep is a Sleep Mode in which the modem runs in a low power state until serial data is detected on the DI
pin.
The period of time the modem sleeps 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 Modes allow modems to periodically wake and check for RF data. The modem wakes according to the
times designated by the Cyclic sleep settings. If the modem detects a wake-up initializer during the time it is awake,
the modem synchronizes with the transmitting modem and receives 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.
While the modem is in Cyclic Sleep Mode, CTS (GPO1) is de-asserted (high) to indicate that data should not be sent to
the modem. When the modem awakens to listen for data, GPO1 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.
The modem remains in Sleep Mode for a user-defined period of time ranging from 0.5 seconds to 16 seconds (SM
parameters 4 through 8). After this interval of time, the modem returns to Idle Mode and listens for a valid data packet
for 100 ms. If the modem does not detect valid data (on any frequency), the modem returns to Sleep Mode. If valid
data is detected, the modem transitions into Receive Mode and receives the incoming RF packets. The modem then
returns to Sleep Mode after a period of inactivity determined by the ST "Time before Sleep" parameter.
The modem can also be configured to wake from cyclic sleep when the GPI2 pin is de-asserted. To configure a modem
to operate in this manner, PW (Pin Wake-up) Command must be issued. Once the GPI2 pin is de-asserted, the modem
is forced into Idle Mode and can begin transmitting or receiving data. It remains active until data is no longer detected
for the period of time specified by the ST Command, at which point it resumes its low-power cyclic state.
Cyclic scanning