73S8024C Data Sheet

DS_8024C_023

6

Rev. 1.3

2

System Controller Interface

•

2 digital inputs allow direct control of the card interface from the host as follows:



Pin

CMDVCC: When low, starts an activation sequence if a card is present.



Pin 5V/

#V: Defines the card voltage.

•

The card I/O and Reset signals have their corresponding controller I/Os to be connected directly to

the host:



Pin RSTIN: controls the card reset signal (when enabled by the sequencer).



Pin I/OUC: data transfer to card I/O contact.



Pins AUX1UC and AUX2UC (auxiliary I/O lines associated to the auxiliary I/O lines to be

connected to the C4 and C8 card connector contacts).

•

2 digital inputs control the card clock frequency division rate: CLKDIV1 and CLKDIV2 define the card

clock frequency, from the input clock frequency (crystal or external clock). The division rate is defined

as follows:

CLKDIV2

CLKDIV1

CLK

0

0

0

1

XTAL

1

0

¼ XTAL

1

1

½ XTAL

When the division rate is equal to 1 (CLKDIV2 =0 and CLKDIV1 = 1), the duty-cycle of the

card clock depends on the duty-cycle and waveform of the signal applied on the pin XTALIN.

When other division rates are used, the 73S8024C circuitry guarantees a duty-cycle in the

range 45% to 55%, conforming to ISO-7816-3, EMV 4.0 and NDS specifications.

•

Interrupt output to the host: As long as the card is not activated, the

OFF pin informs the host about

the card presence only (low = no card in the reader). When

CMDVCC is set low (Card activation

sequence requested from the host), a low level on

OFF means a fault has been detected (e.g. card

removed during a card session, or voltage fault, or thermal / over-current fault) that automatically

initiates a deactivation sequence.

•

Power Down: The PWRDN pin is a digital input that allows the host controller to put the 73S8024C in

its Power Down state. This pin can only be activated out of a card session.

3

Oscillator

The 73S8024C device has an on-chip oscillator that can generate the smart card clock using an external

crystal (connected between the pins XTALIN and XTALOUT) to set the oscillator frequency. When the

card clock signal is available from another source, it can be connected to the pin XTALIN, and the pin

XTALOUT should be left unconnected.