tda8001t NXP Semiconductors, tda8001t Datasheet - Page 7

• Manufacturer Part Number: tda8001t
• Description: Smart Card Interface
• Manufacturer: NXP Semiconductors

Philips Semiconductors
FUNCTIONAL DESCRIPTION
Power supply
The circuit operates within a supply voltage range of
6.7 to 18 V. V
contacts remain inactive during power up or down.
P
The logic part is powered first and is in the reset condition
until V
reaches V
P
When V
the contacts is performed.
Voltage supervisor
This block surveys the 5 V supply of the microcontroller
(V
any transients on card contacts during power up or down
of V
is powered-down.
P
As long as V
connected to pin DELAY, will be discharged. When V
rises to the threshold level, C
ALARM and ALARM remain active, and the sequencer is
blocked until the voltage on the DELAY line reaches V
P
If V
and ALARM become active, and an automatic deactivation
of the contacts is performed.
Clock circuitry (see Fig.5)
The clock signal (CLK) can be applied to the card in two
different methods:
1. Generation by a crystal oscillator: the crystal, or the
2. Use of a signal frequency (up to 20 MHz), already
If CMD7 (respectively CMD3.5) is LOW, the clock signal
(its frequency again divided by two) is enabled and
buffered before being fed to the CLK pin.
1996 Dec 12
OWER UP
OWER DOWN
OWER ON
OWER DOWN
SUP
Smart card interface
SUP
SUP
ceramic resonator (4 to 16 MHz) is connected to the
XTAL pin.
present in the system and connected to the XTAL pin
via a 10 nF capacitor (see Fig.14). In both cases the
frequency is first divided-by-two.
) in order to deliver a defined reset pulse and to avoid
DD
. The voltage supervisor remains active even if V
falls below V
DD
reaches V
th4
falls below V
SUP
+ V
DD
(see Fig.4)
hys4
and GND are the supply pins. All card
is below V
th1
.
th2
. The sequencer is blocked until V
, C
th4
DEL
, an automatic deactivation of
th2
DEL
will be discharged, ALARM
+ V
will be recharged.
hys2
the capacitor C
DEL
SUP
th3
DD
DD
,
.
7
CMD3.5 and internal ENRST are sampled in order to give
the first clock pulse the correct width, and to avoid false
pulses during frequency change.
The CLKOUT2 pins may be used to clock a
microcontroller or an other TDA8001. The signal
available when the circuit is powered up.
State diagram
Once activated, the circuit has six possible modes of
operation:
Figure 6 shows the way these modes are accessible.
I
After reset, the circuit enters the IDLE state. A minimum
number of circuits are active while waiting for the
microcontroller to start a session.
The DETECT line is HIGH if a card is present (PRES and
PRES active) and LOW if a card is not present. The OFF
line is HIGH if no hardware problem is detected.
A
From the IDLE mode, the circuit enters the ACTIVATION
mode when the microcontroller sets the CMDVCC line
(active LOW). The I/O( C) signal must not be LOW.
The internal circuitry is activated, the internal clock starts
and the sequence according to ISO7816 is performed:
The time interval between steps 1 and 2 is 16 s, and
64 s between steps 2 and 3 (see Fig.7).
DLE MODE
CTIVATION SEQUENCE
Idle
Activation
Read
Write
Deactivation
Fault.
All card contacts are inactive
I/O( C) is high impedance
Voltage generators are stopped
Oscillator or XTAL input is running, delivering CLKOUT2
Voltage supervisors are active.
V
V
CLK and RST are enabled.
CC
PP
rises from 0 to 5 V and I/O is enabled
rises from 0 to 5 V
Product specification
TDA8001
1
2
f
xtal
is