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EM4223V2WS11 参数 Datasheet PDF下载

EM4223V2WS11图片预览
型号: EM4223V2WS11
PDF下载: 下载PDF文件 查看货源
内容描述: 只读超高频射频识别设备 [Read-only UHF Radio Frequency Identification Device]
分类和应用: 射频
文件页数/大小: 29 页 / 426 K
品牌: EMMICRO [ EM MICROELECTRONIC - MARIN SA ]
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R
EM4223  
Transponders in the ROUND_STANDBY state will go  
through an internal time-out sequence and will return to  
the ROUND_ACTIVE state after a period equal to 2.5 X  
176 tag bit periods has elapsed since the last MUTE  
command if the WUS bit = 0 (this time-out may be over-  
Each slot has a duration at least as long as the duration  
of a Transponder preamble. The actual duration of the  
slot is determined by the Transponder and is equal to 16  
Transponder bit times. If a Transponder has selected the  
current slot in which to transmit its reply, the Slot length  
is increased for that Transponder to the duration of a  
message length so that the Transponder can send its  
complete message. In order to prevent other tags (those  
that have not yet started their replies) from transmitting  
during the first tag’s reply slot the Reader issues a MUTE  
command to place the tags into the ROUND_STANDBY  
state. After the active Transponder has finished  
transmitting its message, and if the Reader has  
successfully read the Transponder it issues a Next_Slot  
command synchronously with the tag’s signature. If the  
Transponder message was not successfully read then  
the Reader issues a Close_Slot command, which will  
cause all the tags currently in the ROUND_STANDBY  
state to re-enter the ROUND_ACTIVE state.  
ridden  
by  
the  
Transponder  
receiving  
further  
Standby_Round or MUTE commands from the Reader  
which keep the Transponder in the ROUND_STANDBY  
state).  
The  
Transponder  
will  
move  
to  
the  
ROUND_ACTIVE state before the end of time-out period  
if it receives a Next_Slot, Close_Slot, New_Round or  
Wake_Up_FST command.  
When the Transponder has reached the end of a round,  
it will self-trigger a new round, randomly select a new slot  
in which to transmit and it will transmit its identity or data  
when it reaches the selected slot. The process continues  
until the Transponder has been successfully read and  
acknowledged by  
a valid Next_Slot command or  
removed from the RF energizing field.  
The number of slots in a round, referred to as round size,  
is determined by the Reader and is signaled to the  
Transponder in the Wake_Up_FST or New_Round  
command. In the FST mode the tag elects a default  
roundsize of 16, which may be overridden by a Reader  
command, however the FST mode is able to operate  
without any round initializing command. During the  
subsequent collision arbitration process the Reader  
dynamically chooses an optimum round size for the  
following rounds based on the number of collisions  
and/or unproductive time in a round. The number of  
collisions is a function of the number of Transponders in  
the ROUND_ACTIVE state present in the Reader field  
and the current round size. The Reader signals a change  
in round size to Transponders by sending a New_Round  
command containing the required round size.  
If at any time the Transponder receives an Init_Round,  
Init_Round_All or Begin_Round command whether in the  
READY, ROUND_ACTIVE or ROUND_STANDBY  
states, it will immediately switch to the ISO mode of  
operation.  
BOTH TYPES – READ ACKNOWLEDGE  
When a Transponder which has transmitted its data in  
the current slot, receives a Next_slot command, it:  
ƒ
Verifies that the signature in the command matches  
the signature it sent in its last Reply  
ƒ
Verifies that the Next_Slot command has been  
received within the timing window.  
If the Transponder has met these acknowledge  
conditions it enters the Quiet state. Otherwise, it remains  
in the ROUND_ACTIVE state.  
The Transponder on entering the ROUND_ACTIVE State  
or on re-entering the ROUND_ACTIVE state having  
completed a round, selects a pseudo slot at random in  
which to reply. Pseudo slots are equal to Transponder  
preamble in duration. If the Transponder has selected  
the first pseudo slot, it will transmit immediately, if not it  
will hold off until it has reached the selected pseudo-slot  
and then transmit.  
A Transponder in the Quiet state can only be returned to  
the active population by means of a Reset_To_Ready  
command followed by the appropriate round initializing  
command or by removing it from the RF energizing field  
for longer than the persistent sleep time.  
On receiving and recognizing a valid Transponder  
transmission preamble, the Reader sends a MUTE  
command (SOF), which tells all Transponders that have  
not yet started transmitting, to move to the  
ROUND_STANDBY state. When the Reader receives  
FST MODE OPTIONS  
If the FST = 0 set and the WUS = 1, the Transponder will  
wake up in Tag Talks First mode but muted. The first  
Next_Slot command will move the Transponder to the  
ROUND_ACTIVE state and it will enter a round as if it  
had received a Wake_Up command.  
the Transponder Reply without error, it sends  
a
Next_Slot command containing the signature of the  
Transponder that it has just received.  
If both the WUS = 0 and FST = 0 the Transponder will  
move directly to the ROUND_ACTIVE state as if it had  
received a Wake_Up command.  
26  
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Copyright © 2005, EM Microelectronic-Marin SA  
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