tda8035hn NXP Semiconductors, tda8035hn Datasheet - Page 15

• Manufacturer Part Number: tda8035hn
• Description: Smart Card Interface
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TDA8035HN
Product data sheet
8.10 Fault detection
The following fault conditions are monitored by the circuit:
There are two different cases (see
Depending on the type of card presence switch within the connector (normally close or
normally open), and on the mechanical characteristics of the switch, a bouncing may
occur on PRESN signal at card insertion or withdrawal. Consequently, a debounce feature
of approximately 4.05 ms (t
Figure 11 on page 16
debouncing time.
When the card is extracted, an automatic deactivation sequence of the card is performed
on the first True/False transition on PRESN, and OFFN goes Low .
1. Short-circuit or high current on V
2. Card removal during transaction
3. V
4. Overheating.
1. CMDVCCN High: (outside a card session) then, OFFN is Low if the card is not in the
2. CMDVCCN Low: (within a card session) then, OFFN falls Low in any of the
reader, and High if the card is in the reader. A supply voltage drop on V
by the supply supervisor, generates an internal power-on reset pulse, but does not act
upon OFFN. The card is not powered-up, so no short-circuit or overheating is
detected.
aforementioned cases. As soon as the fault is detected, an emergency deactivation is
automatically performed. When the system controller sets CMDVCCN back to High, it
may sense OFFN again after complete deactivation sequence in order to distinguish
between a hardware problem or a card extraction (OFFN will then go back High if the
card is still present).
DDP
or V
DD(INTF)
All information provided in this document is subject to legal disclaimers.
When the card is inserted, OFFN goes High only at the end of the
or Vreg dropping
Rev. 1.0 — 19 April 2011
deb
= 1280 × 1/(fosc(int)_Low) is integrated in the device.
Figure 10 on page
CC
16):
TDA8035HN
Smart card interface
© NXP B.V. 2011. All rights reserved.
DDP
is detected
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