73S8024C Maxim, 73S8024C Datasheet - Page 11

• Manufacturer Part Number: 73S8024C
• Description: The 73S8024C is a single smart card interface IC, compliant to the electrical requirements of ISO 7816-3 and EMV 4
• Manufacturer: Maxim

DS_8024C_023
10 OFF and Fault Detection
There are two cases for which the system controller can monitor the OFF signal: to query regarding the
card presence outside card sessions, or for fault detection during card sessions.
Monitoring Outside a Card Session
In this condition, CMDVCC is always high, OFF is low if the card is not present, and high if the card is
present. Because it is outside a card session, any fault detection will not act upon the OFF signal. No
deactivation is required during this time.
Monitoring During a Card Session
CMDVCC is always low, and OFF falls low if the card is extracted or if any fault is detected. At the same
time that OFF is set low, the sequencer starts the deactivation process.
Figure 6
outside the card session.
Rev. 1.3
CMDVCC
CMDVCC
shows the timing diagram for the CMDVCC, PRES, and OFF signals during a card session and
VCC
t
t
t
For NDS application, C
OFF
RST
CLK
PRES
1
2
5
I/O
VCC
≥ 0.5 µs, timing by 1.5 MHz internal Oscillator
OFF
≥ 7.5 µs
= depends on V
Figure 6: Timing Diagram – Management of the Interrupt Line OFF
outside card session
-- OR --
t
3
≥ 0.5 µs
CC
filter capacitor
F
= 1 µF making t
t
1
t
4
Figure 5: Deactivation Sequence
≥ 0.5 µs
t
2
1
+ t
within card session
t
3
2
+ t
3
+ t
4
t
4
+ t
5
< 100 µs
card extracted
OFF is low by
t
5
73S8024C Data Sheet
within card
session
OFF is low by
any fault
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