XRA00 datasheet(36/40 Pages) STMICROELECTRONICS

36 / 40 page

XRA00

36/40

ANTI-COLLISION FEATURES

Several features of this anti-collision approach de-

serve mention:

■

Each transaction with the XRA00 field is a self-

contained operation. A command - reply pair is

an atomic transaction requiring no knowledge

of previous events from a XRA00 for it to reply.

This feature greatly enhances robustness for

passive XRA00 devices in noisy environments

or at marginal RF power levels.

■

Related to this, the Reader maintains

information about the progress through the

binary tree. Branches that show XRA00

signals, but are not immediately explored may

be held in memory and later examined to

improve the overall throughput.

■

Readers with widely varying capabilities can

make use of the same protocol.

–

A sophisticated Reader that can perform

contention detection within a bin can

perform very rapid sorts of groups of

XRA00 devices. XRA00 devices can be

quickly isolated using a series of PingID

commands, and then read using the

ScrollID command.

–

Simple Readers without the ability to

detect contention (for example, a Reader

with only an analogue filter to look for

"XRA00-like" modulation) can still sort and

identify XRA00 devices using only the

PingID command.

XRA00 Datasheet(PDF) 36 Page - STMicroelectronics