73S8014R Maxim, 73S8014R Datasheet - Page 20

• Manufacturer Part Number: 73S8014R
• Description: The 73S8014R/RN devices are single smart card (ICC) interface circuits, firmware compatible with 8024-type devices for configurations where only asynchronous cards are to be supported, and are derived from the 73S8024RN industry standard electrical i
• Manufacturer: Maxim

3.8 Fault Detection and OFF
There are two different cases that the system controller can monitor the OFF signal: to query regarding the card
presence outside card sessions, or for fault detection during card sessions.
Outside a card session: In this condition, CMDVCC is/are 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.
During a card session: CMDVCC is/are always low, and OFF falls low if the card is extracted or if any fault
detection is detected. At the same time that OFF is set low, the sequencer starts the deactivation process.
Figure 7
the card session:
the card session:
3.9 I/O Circuitry and Timing
The state of the I/O pin is low after power on reset and it goes high when the activation sequencer turns on the
I/O reception state. See the
state of I/OUC is high after power on reset.
Within a card session and when the I/O reception state is turned on, the first I/O line on which a falling edge is
detected becomes the input I/O line and the other becomes the output I/O line. When the input I/O line rising
edge is detected then both I/O lines return to their neutral state.
Figure 8
delay between the I/O signals is shown in
20
shows the timing diagram for the signals CMDVCC, PRES, and OFF during a card session and outside
shows the state diagram of how the I/O and I/OUC lines are managed to become input or output. The
CMDVCC
CMDVCC
VCC
VCC
PRES
PRES
OFF
OFF
Figure 7: Timing Diagram – Management of the Interrupt Line OFF
outside card session
Activation Sequence
Figure
9.
section for details on when the I/O reception is enabled. The
within card session
card extracted
OFF is low by
within card
session
OFF is low by
any fault
Rev. 1.0
e