SRT512-SBN18/1G2 STMICROELECTRONICS [STMicroelectronics], SRT512-SBN18/1G2 Datasheet - Page 21

• Manufacturer Part Number: SRT512-SBN18/1G2
• Description: 13.56 MHz short-range contactless memory chip with 512-bit EEPROM and anticollision functions
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

SRT512
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6.1
6.2
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6.4
6.5
6.6
SRT512 states
The SRT512 can be switched into different states. Depending on the current state of the
SRT512, its logic will only answer to specific commands. These states are mainly used
during the anticollision sequence, to identify and to access the SRT512 in a very short time.
The SRT512 provides 6 different states, as described in the following paragraphs and in
Figure
Power-off state
The SRT512 is in Power-off state when the electromagnetic field around the tag is not
strong enough. In this state, the SRT512 does not respond to any command.
Ready state
When the electromagnetic field is strong enough, the SRT512 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 SRT512.
Inventory state
The SRT512 switches from the Ready to the Inventory state after an Initiate() command has
been issued. In Inventory state, the SRT512 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.
Selected state
In Selected state, the SRT512 is active and responds to all Read_block(), Write_block(), and
Get_UID() commands. When an SRT512 has entered the Selected state, it no longer
responds to anticollision commands. So that the reader can access another tag, the
SRT512 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 SRT512 can be in Selected state at a time.
Deselected state
Once the SRT512 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.
Deactivated state
When in this state, the SRT512 can only be turned off. All commands are ignored.
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SRT512 states
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