DS_8024RN_020

73S8024RN Data Sheet

Rev. 2

7

2 System Controller Interface

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

•

Pin CMDVCC: When low, starts an activation sequence.

•

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

•

Pin 5V/#V: Defines the card voltage.

Card clock is controlled by four digital inputs:

•

CLKDIV1 and CLKDIV2 define the division rate for the clock frequency, from the input clock

frequency (crystal or external clock).

•

CLKSTOP (active high) allows card power down mode by stopping the card clock.

•

CLKLEV defines the card clock level of the card power down mode.

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), low level on OFF means a fault has been detected (e.g. card removal during

card session, or voltage fault, or thermal / over-current fault) that automatically initiates a deactivation

sequence.