tda8004t-c1 NXP Semiconductors, tda8004t-c1 Datasheet - Page 8

• Manufacturer Part Number: tda8004t-c1
• Description: Ic Card Interface
• Manufacturer: NXP Semiconductors

Philips Semiconductors
TDA8004T_4
Product data sheet
8.5 Inactive state
8.6 Activation sequence
After power-on reset, the circuit enters the inactive state. A minimum number of circuits
are active while waiting for the microcontroller to start a session:
After power-on and after the internal pulse width delay, the system controller may check
the presence of the card with the signal OFF (OFF = HIGH while CMDVCC is HIGH
means that the card is present; OFF = LOW while CMDVCC is HIGH means that no card
is present).
If the card is in the reader (which is the case if PRES or PRES is true), the system
controller may start a card session by pulling CMDVCC LOW.
The following sequence then occurs (see
Fig 4. I/O, AUX1 and AUX2 output voltage and current as a function of time during a
•
•
•
•
•
•
•
•
All card contacts are inactive (approximately 200
I/OUC, AUX1UC and AUX2UC are high impedance (10 k pull-up resistor connected
to V
Voltage generators are stopped
XTAL oscillator is running
Voltage supervisor is active
CMDVCC is pulled LOW (t
The voltage doubler is started (t
V
follow V
(1) Current.
(2) Voltage.
CC
DD
LOW-to-HIGH transition
rises from 0 V to 5 V with a controlled slope (t
)
CC
with a slight delay)
Rev. 04 — 20 February 2006
(V)
V
o
6
4
2
0
0
0
)
1
(1)
~ t
20
0
)
Figure
5):
40
(2)
2
t (ns)
= t
to GND)
1
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
fce270
+
1
60
2
3T) (I/O, AUX1 and AUX2
12
8
4
0
(mA)
I
o
TDA8004T
IC card interface
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