AS3956 datasheet(36/107 Pages) AMSCO

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AS3956 − Detailed Description

Configuration Byte AUTH_CNT

Figure 34:

Configuration Byte AUTH_CNT

Note(s):

1. This byte can always be accessed for read and write via the SPI / I²C and can’t be accessed for read and write from the RF side.

This byte indicates the number of allowed unsuccessful

authentication attempts over RF available before disabling the

chip. The byte consists of two separate counters where the

second counter is a copy of the first counter.

These counters are updated at each failed authentication. At

each successful authentication, counters are reset to 7 and, at

each unsuccessful authentication attempt, counters are

decreased by one. If the value of the counters reaches 0, the

chip will be permanently locked and cannot be authenticated

any longer over the RF field. The chip will also be locked in case

the two counter values don’t match. The lock can always be

cleared via SPI / I²C interface.

Conf. Bit

Name

Default

Function

Note

rfu

auth_cnt2<2>

Authentication counter 2

auth_cnt2<1>

auth_cnt2<0>

rfu

auth_cnt1<2>

Authentication counter 1

auth_cnt1<1>

auth_cnt1<0>

AS3956 Datasheet(PDF) 36 Page - ams AG