TCA5013 Datasheet, PDF (25/68 Pages) Texas Instruments – Feature Rich Smartcard Interface IC

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TCA5013
SCPS253B – JANUARY 2014 – REVISED JANUARY 2016
8.4.4.7 Deactivation Sequence
After a card interface has been activated in a certain operating mode, it can be deactivated by I²C command or
certain interrupt events (see Interrupt Operation). The deactivation sequence is the same regardless of what
operating mode the card interface is in.
Figure 7 shows the deactivation sequence initiated by card extraction on the user card interface. It is to be noted
that the deactivation sequence starts 100 µs after the transition on PRES. This delay is intended to provide a
debounce period that provides unintended deactivation due to any glitch on the PRES pin. As mentioned
previously any of the card interfaces may be deactivated due to a supervisor fault, over current fault or over
temperature fault. In these cases there is no debounce period and the deactivation sequence is initiated as soon
as the internal fault signal is asserted.
Figure 8 shows the deactivation of any card interface initiated by I²C command. If the card interface is activated
in asynchronous mode, it can be deactivated by clearing (writing ‘0’) the START_ASYNC bit in the card interface
settings register. To deactivate the user card interface when it is activated in synchronous mode, the
START_SYNC bit should be cleared (write ‘0’).
100 μs
PRES
RST
t
DEAC-TOT
t
DEAC-RST-CLK
+
two
card
clock
cycles
CLK
t _DEAC-RST-IO
IO
t _DEAC-RST-VCC
VCC
< 0.4V
Figure 7. Deactivation Sequence
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