AS3953B datasheet(18/65 Pages) AMSOSRAM

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[v1-04] 2016-Jan-07

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AS3953B − Detailed Description

ATS

ATS is response to ISO 14443-4 command RATS. The content of

the ATS is used to inform the PCD about PICC capability (like

the maximum frame size, support of higher bit rates, etc.)

Several response fields of ATS are stored in EEPROM

configuration word. The AS3953B ATS is composed of following

5 bytes according to [ISO4]: TL, T0, TA(1), TB(1) and TC(1).

TL: This is the length byte. Since ATS is composed of 5 bytes, its

content is 0x05. Figure below defines the coding of the TL byte.

Figure 19:

TL Byte Coding

T0: This is the format byte. Figure below defines the coding of

the T0 byte.

Figure 20:

T0 Byte Coding

Bit b8 is set to ‘0’.

Bits b7 to b5 indicate presence of bytes TA(1), TB(1) and TC(1)

and hence are all set to ‘1’.

Bits b4 to b1 are called FCSI and codes FCS. The FCS is maximum

size of a frame defined by PICC. It is defined by configuration

bits fsci<3:0>.

TA(1): This codes the bit rate capability of PICC. Supported

higher bit rates of AS3953B are 212, 424 and 848 kbit/s. However

in specific applications, it is advised to report lower capability

to PCD (for example, due to the usage of slow controller or low

power application). Due to this reason the TA(1) response is

configurable using configuration bits.

MSB

LSB

Description

0000101

Coding of ATS byte TL

MSB

LSB

Description

fsci<3>

fsci<2>

fsci<1>

fsci<0>

Coding of ATS byte T0

TC(1)

TB(1)

TA(1)

FCSI

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