If the card is in the reader (if PRES is active), the host

microcontroller can begin an activation sequence (start

a card session) by pulling

CMDVCC low. The following

events form an activation sequence (Figure 3):

1) CMDVCC is pulled low.

× T). T is 64 times the

internal oscillator period (approximately 25µs).

(they were previously pulled low).

To apply the clock to the card interface:

1) Set RSTIN high.

2) Set

CMDVCC low.

of RSTIN.

If the applied clock is not needed, set CMDVCC low

RSTIN can be set high to obtain an answer to request

(ATR) from an inserted smart card. Do not perform acti-

vation with RSTIN held permanently high.

Active Mode

When the activation sequence is completed, the

DS8113 card interface is in active mode. The host

microcontroller and the smart card exchange data on

the I/O lines.

Smart Card Interface

10

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ATR

CMDVCC

RST

RSTIN

CLK

VCC

I/O

I/OIN

Figure 3. Activation Sequence Using RSTIN and

CMDVCC