9XTend
‐
PKG
‐
E™
Ethernet
RF
Modem
–
Product
Manual
v2.x4x
[2007.01.04]
©
2007
MaxStream,
Inc.,
Confidential
&
Proprietary
‐
All
Rights
Reserved
14
3 .2 . M ode s of Ope r a t ion
XTend RF Modem s operat e in five m odes.
Figure
3
‐
01. Modes
of
Operation
3 .2 .1 . I dle M ode
When not receiving or t ransm it t ing dat a, t he RF m odem is in I dle Mode. The m odem shift s int o t he
ot her m odes of operat ion under t he follow ing condit ions:
• Transm it Mode ( Serial dat a is r eceived in t he DI Buffer)
• Receive Mode ( Valid RF dat a is received t hrough t he ant enna)
• Sleep Mode ( Sleep Mode condit ion is m et )
• Com m and Mode ( Com m and Mode Sequence is issued)
3 .2 .2 . Tr a n sm it M ode
When t he fir st byt e of ser ial dat a is received from t he UART in t he DI buffer, t he m odem at t em pt s
t o shift t o Transm it Mode and init iat e an RF connect ion wit h ot her m odem s. Aft er t ransm ission is
com plet e, t he m odem r et ur ns t o I dle Mode.
RF t r a n sm ission be gin s a ft e r e it h e r of t h e follow in g cr it e r ia is m e t :
Figure
3
‐
02. Transmit
Mode
Data
Flow
The charact er t im eout t rigger can be
disabled by set t ing RO t o zer o. I n t his
case, t ransm ission w ill not begin unt il
RB byt es have been received and are
pending for RF t ransm ission. The RB
param et er m ay be set t o any value
bet w een 1 and t he RF packet size [ refer
t o PK ( Max RF Packet Size) param et er] ,
inclusive. Not e t hat t ransit ion t o Trans-
m it Mode cannot t ake place during RF
recept ion; t he RF recept ion m ust com -
plet e before t he radio can t ransit ion int o
Transm it Mode.
I f RB or RO condit ions are m et , t he
m odem init ializes a com m unicat ions channel. Serial dat a in t he DI buffer is grouped int o RF pack-
et s ( up t o 2048 byt es in each packet , r efer t o PK Com m and) , conver t ed t o RF dat a and is t ransm it -
t ed over- t he- air unt il t he DI buffer is em pt y.
1.
RB byt es have been received by t he UART and are pending for RF t ransm ission.
[ Refer t o t he RB ( Packet izat ion Thr eshold) Com m and]
2.
At least one charact er has been received by t he UART and is pending for RF t ransm ission;
and RO charact er t im es of silence been observed on t he UART.
[ Refer t o t he RO ( Packet izat ion Tim eout ) Com m and]
