M24LR64E-R datasheet(77/140 Pages) STMICROELECTRONICS

77 / 140 page

M24LR64E-R

Inventory Initiated command

Doc ID 022712 Rev 3

77/140

Inventory Initiated command

The M24LR64E-R provides a special feature to improve the inventory time response of

moving tags using the Initiate_flag value. This flag, controlled by the Initiate command,

allows tags to answer Inventory Initiated commands.

For applications in which multiple tags are moving in front of a reader, it is possible to miss

tags using the standard inventory command. The reason is that the inventory sequence has

to be performed on a global tree search. For example, a tag with a particular UID value may

have to wait the run of a long tree search before being inventoried. If the delay is too long,

the tag may be out of the field before it has been detected.

Using the Initiate command, the inventory sequence is optimized. When multiple tags are

moving in front of a reader, the ones which are within the reader field are initiated by the

Initiate command. In this case, a small batch of tags answers to the Inventory Initiated

command, which optimizes the time necessary to identify all the tags. When finished, the

reader has to issue a new Initiate command in order to initiate a new small batch of tags

which are new inside the reader field.

It is also possible to reduce the inventory sequence time using the Fast Initiate and Fast

Inventory Initiated commands. These commands allow the M24LR64E-Rs to increase their

response data rate by a factor of 2, up to 53 Kbit/s.

M24LR64E-R 数据表(PDF) 77 Page - STMicroelectronics