ST8024LCDR STMicroelectronics, ST8024LCDR Datasheet - Page 18

• Manufacturer Part Number: ST8024LCDR
• Description: IC INTERFACE SMART CARD 28SOIC
• Manufacturer: STMicroelectronics

Specifications of ST8024LCDR

• Featured Product: STM32 Cortex-M3 Companion Products
• Applications: Smart Card Reader, Writer
• Voltage - Supply: 2.7 V ~ 6.5 V
• Package / Case: 28-SOIC (0.300", 7.50mm Width)
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Interface: -

Functional description
5.4
5.5
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The frequency change is synchronous, which means that during transition no pulse is
shorter than 45 % of the smallest period, and that the first and last clock pulses about the
instant of change have the correct width.
When changing the frequency dynamically, the change is effective for only eight periods of
XTAL1 after the command. The duty factor of f
XTAL1. In order to reach a 45 to 55 % duty factor on pin CLK, the input signal on pin XTAL1
should have a duty factor of 48 to 52 % and transition times of less than 5 % of the input
signal period.
If a crystal is used, the duty factor on pin CLK may be 45 to 55 % depending on the circuit
layout and on the crystal characteristics and frequency. In other cases, the duty factor on pin
CLK is guaranteed between 45 and 55 % of the clock period.
The crystal oscillator runs as soon as the IC is powered up. If the crystal oscillator is used,
or if the clock pulse on pin XTAL1 is permanent, the clock pulse is applied to the card as
shown in the activation sequences shown in
If the signal applied to XTAL1 is controlled by the system microcontroller, the clock pulse will
be applied to the card when it is sent by the system microcontroller (after completion of the
activation sequence).
I/O transceivers
The three data lines I/O, AUX1 and AUX2 are identical.The idle state is realized by both I/O
and I/OUC lines being pulled high via a 11 kΩ resistor (I/O to V
I/O is referenced to V
equal to V
An anti-latch circuit disables the detection of falling edges on the line of the other side, which
then becomes a slave. After a time delay t
on, thus transmitting the logic 0 present on the master side. When the master side returns to
logic 1, a P transistor on the slave side is turned on during the time delay t
sides return to their idle states. This active pull-up feature ensures fast low-to-high
transitions; it is able to deliver more than 1 mA at an output voltage of up to 0.9 V
80 pF load. At the end of the active pull-up pulse, the output voltage depends only on the
internal pull-up resistor and the load current. The current to and from the card I/O lines is
limited internally to 15 mA and the maximum frequency on these lines is 1 MHz.
Inactive mode
After a power-on reset, the circuit enters the inactive mode. A minimum number of circuits
are active while waiting for the microcontroller to start a session:
– All card contacts are inactive (approximately 200 Ω to GND)
– Pins I/OUC, AUX1UC and AUX2UC are in the high-impedance state (11 kΩ pull-up
– Voltage generators are stopped
– XTAL oscillator is running
– Voltage supervisor is active
– The internal oscillator is running at its low frequency.
resistor to V
DD
. The first side of the transceiver to receive a falling edge becomes the master.
DD
). Applies only to SO-28 and TSSOP-28 packages.
CC
, and pin I/OUC to V
Doc ID 17709 Rev 3
d(edge)
DD
Figure 5
XTAL
, thus allowing operation when V
, an N transistor on the slave side is turned
depends on the signal present at pin
and
Figure 6
CC
and I/OUC to V
pu
and then both
CC
CC
DD
ST8024L
is not
). Pin
into an