tda8004at-c1 NXP Semiconductors, tda8004at-c1 Datasheet - Page 8

• Manufacturer Part Number: tda8004at-c1
• Description: Ic Card Interface
• Manufacturer: NXP Semiconductors

Philips Semiconductors
TDA8004AT_3
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 microcontroller 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 microcontroller
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
(I/O, AUX1 and AUX2 follow V
internal oscillator, approximately 25 s
(1) Current.
(2) Voltage.
CC
DD
LOW-to-HIGH transition
rises from 0 V to 5 V or from 0 V to 3 V with a controlled slope (t
)
Rev. 03 — 9 February 2006
(V)
V
o
6
4
2
0
0
0
)
CC
1
(1)
with a slight delay); T is 64 times the period of the
~ t
20
0
)
Figure
5):
40
(2)
t (ns)
to GND)
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
fce661
60
12
8
4
0
(mA)
TDA8004AT
I
o
IC card interface
2
= t
1
+
1
2
3T)
8 of 25