73S8009C Maxim, 73S8009C Datasheet - Page 22

• Manufacturer Part Number: 73S8009C
• Description: The 73S8009C is a versatile power management and single smart card interface circuit that is ideally suited for smart card reader products that are battery- and/or USB bus-powered
• Manufacturer: Maxim

73S8009C Data Sheet
3.7
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 (#/%) 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, no fault detection can occur
and it will not act upon the OFF signal. No deactivation is required during this time.
During a card session: CMDVCC# and/or CMDVCC% is 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 and the host should stop all transitions on the signal lines.
Figure 7 shows the timing diagram for the signals CMDVCC (#/%), PRES, and OFF during a card session
and outside the card session.
22
VCC_ON
CMDVCC
CMDVCC
OFF and Fault Detection
VCC
RST
CLK
I/O
PRES
VCC
OFF
outside card session
t1
Figure 6: Deactivation Sequence
t2
Figure 7: OFF Activity
within card session
t3
t4
card extracted
OFF is low by
t5
within card
session
OFF is low by
DS_8009C_025
any fault
Rev. 1.5