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Philips Semiconductors
Smart card interface
R
EAD MODE
When the activation sequence is completed and, after the
card has replied its Answer-to-Reset, the TDA8001 will be
in the READ mode. Data is exchanged between the card
and the microcontroller via the I/O line.
W
RITE MODE
Cards with EPROM memory need a programming voltage
(V
). When it is required to write to the internal memory
PP
of the card, the microcontroller sets one of the VPP12.5,
VPP15 and VPP21 lines LOW, according to the
programming value given in the Answer-to-Reset.
V
rises from 5 V to the selected value with a typical slew
PP
rate of 0.38 V/ s. In order to respect the ISO 7816 slopes,
the circuit generates V
PP
internal capacitor. The voltage on this capacitor is then
amplified by a power stage gain of 5, powered via an
external supply pin V
H
D
EACTIVATION SEQUENCE
When the session is completed, the microcontroller sets
the CMDVCC line to its HIGH state. The circuit then
executes an automatic deactivation sequence by counting
the sequencer back:
RST falls to LOW and CLK is stopped
I/O( C) becomes high impedance and V
V
falls to 0 V.
CC
handbook, full pagewidth
V SUP
V DELAY
ALARM
1996 Dec 12
by charging and discharging an
(30 V max).
(see Fig.8)
PP
Fig.4 Alarm and delay as a function of V
The circuit returns to the IDLE mode on the next rising
edge of the clock.
P
ROTECTIONS
Main fault conditions are monitored by the circuit:
Short-circuit or overcurrent on V
Short-circuit or overcurrent on V
Card extraction during transaction
Overheating problem
V
SUP
V
drop-out.
DD
When one of these fault conditions is detected, the circuit
pulls the interrupt line OFF to its active LOW state and
returns to the FAULT mode. The current on I/O is internally
limited to 5 mA.
F
AULT MODE
When a fault condition is written to the microcontroller via
the OFF line, the circuit initiates a deactivation sequence.
After the deactivation sequence has been completed, the
OFF line is reset to its HIGH state after the microcontroller
has reset the CMDVCC line HIGH.
falls to 0 V
t d
(C
SUP
8
drop-out
(see Fig.9)
fixes the pulse width).
DEL
Product specification
TDA8001
CC
PP
V th2
V hys2
V th2
V th3
MGG818
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