UM1582
User manual
24-pin smartcard interface ST8034HN demonstration board
Introduction
The purpose of this document is to describe, and provide information on, how to efficiently
use the ST8034HN smartcard interface device demonstration board.
The ST8034xx is a family of complete smartcard interface devices, compatible with ISO
7816, NDS and EMV™ 4.3 payment systems that provide selectable supply voltage for the
smartcard with automatic deactivation sequence in case of overload, short-circuit or
undervoltage, with programmable internal or external clock signal, reset signal and
protected I/O data lines. The ST8034HC and ST8034C product variants also provide a chip
select function that allows the device interface to be isolated from the microcontroller bus
signals and to share the bus among multiple card interface devices in a parallel
combination.
In summary, ST8034xx interface devices are placed between the smartcard and the
microcontroller to provide all supply, protection, detection and control functions, with just
minimum external components.
Figure 1. Demonstration board with card connector and microcontroller board interface
April 2013
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www.st.com
Applications
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1
Applications
Smartcard readers for
Set-top boxes
Pay-TV
Identification
Tachographs
Banking
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Description
2
Description
Figure 2. Demonstration board description
2.1
Use of the demonstration board
The ST8034HN demonstration board is designed both for standalone operation or to be fully
controlled by the microcontroller; it is fully configurable and provides access to all the
signals including supply voltages through labeled test points and uses a standard connector
for a simple communication interface with the microcontroller block. The labeled test points
on the board are in the same order as the signals in the flat interface cable.
The following blocks provide the demonstration board configurability:
Crystal clock oscillator (10 MHz): can be used to provide card clock in a standalone
operation.
Card clock source selection switch: allows selection between the onboard crystal
oscillator as the card clock source (clock source switch position “Xtal”), or an external
clock source provided by the microcontroller block through the MCU interface together
with the data signals (clock source switch position “Ext”).
Card supply (V
CC
) selection switches: the demonstration board provides easy but
flexible card supply voltage selection either by the onboard configuration switches or by
the microcontroller. Put the VCC_SEL1 and VCC_SEL2 switches to the position
“V
DD(INTF)
” (logic high level) or “GND” (logic low level) to select the desired V
CC
value
(5.0 V, 3.0 V or 1.8 V) according to
Table 1,
or to the center position (“MCU”) which
connects this signal to the microcontroller interface to allow its control of these input
signals.
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Description
Table 1. V
CC
selection by VCC_SEL1 and VCC_SEL2 switches
VCC_SEL1 position
GND
V
DD(INTF)
V
DD(INTF)
MCU
VCC_SEL2 position
x
(1)
V
DD(INTF)
GND
MCU
V
CC
1.8 V
5V
3V
UM1582
Set by the microcontroller
1. x = don't care, however, please note that a combination of VCC_SEL1 = VCC_SEL2 = GND and
CMDVCC = high puts the ST8034HN device into a deep shutdown mode.
For an easy connection of oscilloscope probes to the test points, remove the plastic tip with
the hook from the probes and insert the center pin into the test point terminal. Ground test
points are available in a sufficient amount throughout the board.
2.2
Smartcard interface
The demonstration board contains a full size smartcard connector. Insert the smartcard from
the right-hand side, card contacts facing down. Card presence detection is implemented
(a presence switch inside the card connector, normally open).
2.3
Interface to a microcontroller block
A standard 16-pin header connector with a standard cable is used to interconnect the
ST8034HN demonstration board module with a microcontroller block. The voltage level for
communication on this interface is V
DD(INTF)
.
2.4
Default functionality notes
No floating pins: for simple standalone testing, all the input signal levels are softly
defined by pull-up or pull-down resistors on the board, refer to
Figure 4: Schematic
diagram.
The PORADJ undervoltage threshold on the V
DD(INTF)
supply voltage (UVLO) is set by
R1 and R2 to 1.5 V typ. The resistors can be replaced with different values to set
different undervoltage thresholds on V
DD(INTF)
:
V
DD(INTF)
UVLO threshold (falling) = (R1 + R2) / R2 x V
TH(PORADJ)
V
DD(INTF)
UVLO threshold (rising) = (R1 + R2) / R2 x (V
TH(PORADJ)
+ V
HYST(PORADJ)
)
For detailed specifications of the voltage threshold values, refer to Table 6 of the ST8034HN
datasheet.
The sum of R1 + R2 should be about 100 k, which is a good compromise between
a sufficient robustness and a minimum current consumption.
Please consider tolerance ranges of the resistors used in the resistor divider and
specifications range of the V
TH(PORADJ)
to make sure that even in the worst case the real
V
DD(INTF)
undervoltage deactivation threshold does not fall in the desired operating voltage
range (i.e. consider also voltage supply tolerance range).
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Board layout
3
3.1
Board layout
Layout recommendations
The ST8034xx family of devices includes an LDO block to generate V
CC
supply voltage for
the smartcard, which (in contrast to previous ST8024/8024L devices with a charge pump)
does not generate any noise and therefore even the requirements for a printed circuit board
layout and external component selection are not so strict (general PCB layout rules apply).
On the other hand, the LDO requires the input voltage (V
DDP
) to be at least about 100 mV
greater than the desired output voltage (V
CC
). Place the decoupling capacitors as close as
possible to the appropriate pin of the ST8034 device and use sufficiently wide PCB tracks.
Make the data and clock lines as short as possible and use a ground plane.
3.2
Component placement
Figure 3. Component placement on the PCB
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