SRI4K-A3T/1GE STMicroelectronics, SRI4K-A3T/1GE Datasheet - Page 14

• Manufacturer Part Number: SRI4K-A3T/1GE
• Manufacturer: STMicroelectronics

Specifications of SRI4K-A3T/1GE

• Operating Temperature (max): 85C
• Operating Temperature Classification: Commercial
• Lead Free Status / Rohs Status: Compliant

SRI4K
SRI4K OPERATION
All commands, data and CRC are transmitted to
the SRI4K as 10-bit characters using ASK modu-
lation. The start bit of the 10 bits, b
The command frame received by the SRI4K at the
antenna is demodulated by the 10% ASK demod-
ulator, and decoded by the internal logic. Prior to
any operation, the SRI4K must have been select-
ed by a SELECT command. Each frame transmit-
ted to the SRI4K must start with a Start Of Frame,
followed by one or more data characters, two CRC
Bytes and the final End Of Frame. When an invalid
SRI4K STATES
The SRI4K can be switched into different states.
Depending on the current state of the SRI4K, its
logic will only answer to specific commands.
These states are mainly used during the anti-colli-
sion sequence, to identify and to access the
SRI4K in a very short time. The SRI4K provides 6
different states, as described in the following para-
graphs and in
POWER-OFF State
The SRI4K is in POWER-OFF state when the
electromagnetic field around the tag is not strong
enough. In this state, the SRI4K does not respond
to any command.
READY State
When the electromagnetic field is strong enough,
the SRI4K 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 SRI4K.
INVENTORY State
The SRI4K switches from the READY to the IN-
VENTORY state after an INITIATE() command
has been issued. In INVENTORY state, the SRI4K
will respond to any anti-collision commands: INI-
TIATE(), PCALL16() and SLOT_MARKER(), and
14/41
Figure
21..
0
, is sent first.
frame is decoded by the SRI4K (wrong command
or CRC error), the memory does not return any er-
ror code.
When a valid frame is received, the SRI4K may
have to return data to the reader. In this case, data
is returned using BPSK encoding, in the form of
10-bit characters framed by an SOF and an EOF.
The transfer is ended by the SRI4K sending the 2
CRC Bytes and the EOF.
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 com-
mand matches its own. If not, it will remain in IN-
VENTORY state.
SELECTED State
In SELECTED state, the SRI4K is active and re-
sponds to all READ_BLOCK(), WRITE_BLOCK()
and GET_UID() commands. When an SRI4K has
entered the SELECTED state, it no longer re-
sponds to anti-collision commands. So that the
reader can access another tag, the SRI4K 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 DEACTIVAT-
ED state by issuing a COMPLETION() command.
Only one SRI4K can be in SELECTED state at a
time.
DESELECTED State
Once the SRI4K 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 SRI4K can only be turned
off. All commands are ignored.