09.03.2013 Views

BLOCKING READER: DESIGN AND IMPLEMENTATION OF A ...

BLOCKING READER: DESIGN AND IMPLEMENTATION OF A ...

BLOCKING READER: DESIGN AND IMPLEMENTATION OF A ...

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Table 4.4. Link timing parameters [3]<br />

Parameter Minimum Typical Maximum Description<br />

T1<br />

MAX(RT cal, 10Tpri)<br />

× (1 − F T ) − 2µ s<br />

MAX(RT cal, 10Tpri) MAX(RT cal, 10Tpri)<br />

× (1 − F T ) + 2µ s<br />

Time from interrogrator<br />

transmission to tag response,<br />

measured at antenna<br />

terminal.<br />

T2 3.0Tpri 20.0Tpri Time from last falling<br />

edge of the last bit of<br />

the Tag response to first<br />

falling edge of a Reader<br />

signal.<br />

T3 0.0Tpri Time an Reader waits, after<br />

T1,before it issues another<br />

command<br />

T4 2.0Tpri Minimum time between<br />

Reader commands<br />

4.3.5 Reader Commands and Tag replies<br />

Reader-to-Tag commands shall have the format shown in the Table 4.5. Each<br />

and every command shall have a command code preceding the commands. It is<br />

unique to every command. The Table 4.5 indicates the codes and length of the few<br />

commands.The Tags shall ignore invalid commands. Following shall be the reasons<br />

for the commands to be invalid.<br />

• If the current Tag state is incorrect.<br />

• Command not supported by Tag.<br />

• If the parameters are incorrect.<br />

• If the CRC error is detected.<br />

• An incorrect section is specified.<br />

• Other unrecognized encoding/signaling.<br />

A CRC-5 is 5 bits of length is defined by the polynomial shown in the Equa-<br />

tion 4.2. The preset value is 01001 and residue 00000.<br />

38

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!