XStream
‐
PKG
‐
T™
Telephone
RF
Modem
–
Product
Manual
v5.x00
[2006.02.24]
The module remains in Sleep Mode for a user-defined period of time ranging from 0.5 seconds to
16 seconds (SM Parameters 3 through 8). After this interval of time, the module returns to Idle
Mode and listens for a valid data packet for 100 ms. If the module does not detect valid data (on
any frequency), the module returns to Sleep Mode. If valid data is detected, the module
transitions into Receive Mode and receives incoming RF packets. The module then returns to
Sleep Mode after a Period of inactivity that is determined by ST “Time before Sleep” Command.
The module can also be configured to wake from cyclic sleep when DI3 (SLEEP) is de-asserted
(low). To configure a module to operate in this manner, PW (Pin Wake-up) Command must be
issued. Once DI3 is de-asserted, the module is forced into Idle Mode and can begin transmitting
or receiving data. It remains active until no data is detected for the period of time specified by
the ST Command, at which point it resumes its low-power cyclic state.
Note: The cyclic interval time defined by SM (Sleep Mode) Command must be shorter than the interval
time defined by LH (Wake-up Initializer Timer).
For example: If SM=4 (Cyclic 1.0 second sleep), the LH Parameter should equal 0x0B (“1.1” seconds).
With these parameters set, there is no risk of the receiving module being asleep for the duration of
wake-up initializer transmission. “Cyclic Scanning” explains in further detail the relationship between
“Cyclic Sleep” and “Wake-up Initializer Timer”
Cyclic Scanning.
Each RF transmission consists of an RF Initializer and payload. The wake-up
initializer contains initialization information and all receiving modules must wake during the
wake-up initializer portion of data transmission in order to be synchronized with the transmitting
module and receive the data.
Figure
2
‐
06.
Correct
Configuration
(LH
>
SM):
Length
of
the
wake
‐
up
initializer
exceeds
the
time
interval
of
Cyclic
Sleep.
The
receiver
is
guaranteed
to
detect
the
wake
‐
up
initializer
and
receive
the
accompanying
payload
data.
Figure
2
‐
07.
Incorrect
Configuration
(LH
<
SM):
Length
of
wake
‐
up
initializer
is
shorter
than
the
time
interval
of
Cyclic
Sleep.
This
configuration
is
vulnerable
to
the
receiver
waking
and
missing
the
wake
‐
up
initializer
(and
therefore
also
the
accompanying
payload
data).
©
2006
MaxStream,
Inc.,
Confidential
and
Proprietary
13
