9XTend
‐
PKG
‐
E™
Ethernet
RF
Modem
–
Product
Manual
v2.x4x
[2007.01.04]
©
2007
MaxStream,
Inc.,
Confidential
&
Proprietary
‐
All
Rights
Reserved
16
3 .2 .3 . Re ce ive M ode
I f a m odem det ect s RF dat a w hile operat ing in I dle Mode, t he m odem t ransit ions t o Receive Mode
t o st art receiving RF packet s. Once a packet is received, t he m odem checks t he CRC ( cyclic redun-
dancy check) t o ensure t hat t he dat a was t ransm it t ed wit hout error. I f t he CRC dat a bit s on t he
incom ing packet are invalid, t he packet is discarded. I f t he CRC is valid, t he packet proceeds t o t he
DO Buffer.
Figure
3
‐
04. Receive
Mode
Data
Flow
*
Refer
to
the
‘Address
Recognition’
sec
‐
tion
for
more
information
regarding
address
recognition.
The m odem ret urns t o I dle Mode
w hen valid RF dat a is no longer
det ect ed or aft er an error is
det ect ed in t he r eceived RF dat a. I f
serial dat a is st ored in t he DI
buffer w hile t he m odem is in
Receive Mode, t he serial dat a w ill
be t ransm it t ed aft er t he m odem is
finished receiving dat a and ret urns
t o I dle Mode.
3 .2 .4 . Sle e p M ode
Soft w a r e Sle e p
Sleep Modes enable t he m odem t o ent er st at es of low- power consum pt ion when not in use. Three
soft ware Sleep Modes are support ed:
• Serial Port Sleep ( Wake on Serial Port act ivit y)
• Cyclic Sleep ( Wake on RF act ivit y)
I n order t o ent er Sleep Mode, t he follow ing condit ion m ust be m et ( in addit ion t o t he m odem hav-
ing a non- zero SM param et er value) :
When in Sleep Mode, t he m odem will not t ransm it or receive dat a unt il t he m odem first t ransit ions
t o I dle Mode. All Sleep Modes are enabled and disabled using SM Com m and. Transit ions int o and
out of Sleep Modes are t riggered by various m echanism s as show n in t he t able below.
The m odem is idle ( no dat a t ransm ission or r ecept ion) for t he am ount of t im e defined by t he ST
( Tim e before Sleep) param et er. [ NOTE: ST is only act ive w hen SM = 4- 5.]
Table
3
‐
01.
Summary
of
Sleep
Mode
Configurations
Sleep Mode
(Setting)
Transition into
Sleep Mode
Transition out of Sleep
Mode (wake)
Related
Commands
Power
Consumption
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
< 210 mA
Cyclic Sleep
(SM = 4 - 8)
RF modem 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 modem can be forced into Idle Mode using the SLEEP pin if the
PW (Pin Wake-up) command is issued.
(SM), ST, HT,
LH, PW
< 210 - 224 mA
when sleeping
(SM=4, 1 sec.,
@120K baud)
