SRIX4K datasheet(21/50 Pages) STMICROELECTRONICS

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SRIX4K

SRIX4K states

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SRIX4K states

The SRIX4K can be switched into different states. Depending on the current state of the

SRIX4K, its logic will only answer to specific commands. These states are mainly used

during the anticollision sequence, to identify and to access the SRIX4K in a very short time.

The SRIX4K provides 6 different states, as described in the following paragraphs and in

Figure 19.

6.1

POWER-OFF state

The SRIX4K is in POWER-OFF state when the electromagnetic field around the tag is not

strong enough. In this state, the SRIX4K does not respond to any command.

6.2

READY state

When the electromagnetic field is strong enough, the SRIX4K enters the READY state. After

Power-up, the Chip_ID is initialized with a random value. The whole logic is reset and

remains in this state until an INITIATE() command is issued. Any other command will be

ignored by the SRIX4K.

6.3

INVENTORY state

The SRIX4K switches from the READY to the INVENTORY state after an INITIATE()

command has been issued. In INVENTORY state, the SRIX4K will respond to any

anticollision commands: INITIATE(), PCALL16() and SLOT_MARKER(), and then remain in

the INVENTORY state. It will switch to the SELECTED state after a SELECT(Chip_ID)

command is issued, if the Chip_ID in the command matches its own. If not, it will remain in

INVENTORY state.

6.4

SELECTED state

In SELECTED state, the SRIX4K is active and responds to all READ_BLOCK(),

WRITE_BLOCK(), AUTHENTICATE() and GET_UID() commands. When an SRIX4K has

entered the SELECTED state, it no longer responds to anticollision commands. So that the

reader can access another tag, the SRIX4K can be switched to the DESELECTED state by

sending a SELECT(Chip_ID2) with a Chip_ID that does not match its own, or it can be

placed in DEACTIVATED state by issuing a COMPLETION() command. Only one SRIX4K

can be in SELECTED state at a time.

6.5

DESELECTED state

Once the SRIX4K is in DESELECTED state, only a SELECT(Chip_ID) command with a

Chip_ID matching its own can switch it back to SELECTED state. All other commands are

ignored.

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