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april 2013 docid023836 rev 1 1/9 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 smar tcard 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, protecti on, detection and control functions, with just minimum external components. figure 1. demonstration board with card connector and microcontroller board interface www.st.com
applications UM1582 2/9 docid023836 rev 1 1 applications smartcard readers for ? set-top boxes ? pay-tv ? identification ? tachographs ? banking docid023836 rev 1 3/9 UM1582 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 mi crocontroller 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 de monstration board configurability: ? crystal clock oscillator (10 mhz): can be us ed to provide card clock in a standalone operation. ? card clock source selection switch: allo ws selection between the onboard crystal oscillator as the card cl ock 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 sour ce 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 a nd 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. description UM1582 4/9 docid023836 rev 1 for an easy connection of oscillo scope probes to the test point s, 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 do wn. 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 th is interface is v dd(intf) . 2.4 default functionality notes ? no floating pins: for simple standalone testi ng, 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 thre shold 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 re sistors 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). table 1. v cc selection by vcc_sel1 and vcc_sel2 switches vcc_sel1 position vcc_sel2 position v cc gnd x (1) 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. 1.8 v v dd(intf) v dd(intf) 5 v v dd(intf) gnd 3 v mcu mcu set by the microcontroller docid023836 rev 1 5/9 UM1582 board layout 3 board layout 3.1 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 ca pacitors 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 schematic diagram UM1582 6/9 docid023836 rev 1 4 schematic diagram figure 4. schematic diagram 6 0 $ 5 7 & |