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AS3953

Datasheet - D e t a il e d D es c r i pt io n

Third Byte of UID (uid2).

Third byte of UID –

uid<23:16> is set to 00(hex). Table below defines the coding of the first three bytes of UID.

The last 4 bytes of UID are read from EEPROM (UID word). Table below defines the last four bytes of UID.

7.5.2 Coding of ATQA, SAK and ATS

Several bits of responses ATQA, SAK and ATS are defined as “don’t care” in the ISO 14443A standard. Some others are defined by optional

choices in standard protocol. This section defines how these bits are set by the AS3953.

ATQA.

ATQA is response to

REQA and WUPA commands. Table below defines the ATQA coding.

Bits

b16 to b13 are RFU bits which must be set to ‘0’.

Bits

b12 to b9 are proprietary coding and are set to ‘0’.

Bits

b8 and b7 indicate double size UID.

Bit

b6 is ‘RFU’ bit and is set to ‘0’.

For bit frame anti-collision, the code 00100 is chosen.

SAK.

SAK is response to

SELECT command. AS3953 UID has double size, which defines SAK responses for Cascade Level 1 and Cascade Level 2.



Cascade Level 1: According to ISO 14443-3, all bits except

b3 are “don’t care” for Cascade Level 1. Table below defines Cascade Level 1

coding.



Cascade Level 2: According to ISO 14443-3 all bits except

b6 and b3 are “don’t care” for Cascade Level 2.

If configuration

bit16 [nl4] is set to logic ‘0’ (default state), the SAK on Cascade Level 2 reports that tag is compliant to level4 (see table below).

If configuration

bit16 [nl4] is set to logic ‘1’, the SAK on Cascade Level 2 reports that tag is NOT compliant to Level-4 (see table below).

UID Byte

FL Signal Name

Value (hex)

uid0

uid<7:0>

3F

uid1

uid<15:8>

10

uid2

uid<23:16>

00

UID Byte

UID Word Bits

uid3

b7-b0

uid4

b15-b8

uid5

b23-b16

uid6

b31-b24

b16

b15

b14

b13

b12

b11

b10

b9

b8

b7

b6

b5

b4

b3

b2

b1

0

0000000010001

00

UID size

Bit frame anti-collision

b8

MSB

b7

b6

b5

b4

b3

b2

b1

LSB

Description

0

00001

00

Cascade bit set: UID not complete

b8

MSB

b7

b6

b5

b4

b3

b2

b1

LSB

Description

0

0

1

000

00

UID complete, tag is compliant to

ISO/IEC14443-4

b8

MSB

b7

b6

b5

b4

b3

b2

b1

LSB

Description

0

0000000

UID complete, tag is NOT compliant

to ISO/IEC14443-4