st8004 STMicroelectronics, st8004 Datasheet - Page 19

• Manufacturer Part Number: st8004
• Description: Smartcard Interface
• Manufacturer: STMicroelectronics

ST8004
Functional description
When OFF level falls low, the system controller must wait not less than 160µs before setting
high again the CMDV
command.
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Depending on the type of card presence switch within the connector (normally closed or
normal open), and on the mechanical characteristics of the switch, a bouncing may occur on
presence signals at card insertion or withdrawal. There is no debounce feature in the device,
so the software has to take it into account; however, the detection of card take off during
active phase, which initiates an automatic deactivation sequence is done on the first
True/False transition on PRES or PRES, and is memorized until the system controller sets
CMDV
High. So, the software may take some time waiting for presence switches to be
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stabilized without causing any delay on the necessary fast and normalized deactivation
sequence.
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