5

AT83C23OK

4307CS–SCR–03/07

RST

16

16

VCC

I/0

Reset Input

applied, whether or not the oscillator is running.

This pin has an internal 10K pull-up resistor which allows the device to be reset by

connecting a capacitor between this pin and VSS.

Asserting RST when the chip is in Idle mode or Power-Down mode returns the chip

to normal operation.

The output is active for at least 12 oscillator periods when an internal reset occurs.

D+

29

29

DVCC

I/O

For Serial reader: Connect this pin to GND.

For USB reader:

USB Positive Data Upstream Port

This pin requires an external serial resistor of 27

Ω (AT8xC122) or 33Ω

(AT83C5123) and a 1.5 K

D-

28

28

DVCC

I/O

For Serial reader: Connect this pin to GND.

For USB reader:

USB Negative Data Upstream Port

This pin requires an external serial resistor of 27

Ω (AT8xC122) or 33Ω

(AT83C5123)

30

30

AVCC

O

For Serial reader: Leave this pin unconnected.

For USB reader:

USB Voltage Reference: 3.0 <

controlled by software.

XTAL1

14

14

VCC

I

Input to the on-chip inverting oscillator amplifier

To use the internal oscillator, a crystal or an external oscillator must be connected to

this pin.

XTAL2

15

15

VCC

O

Output of the on-chip inverting oscillator amplifier

To use the internal oscillator, a crystal circuit must be connected to this pin. If an

external oscillator is used, leave XTAL2 unconnected.

PLLF

26

26

AVCC

O

PLL Low Pass Filter input

Receives the RC network of the PLL low pass filter.

AVCC

27

27

PWR

Analog Supply Voltage

AVCC is used to supply the internal 3.3V analog regulator which supplies the

internal USB driver

VCC

12

12

PWR

Supply Voltage

VCC is used to supply the internal 3.3V digital regulator which supplies the PLL,

CPU core and internal I/O’s

LI

10

10

PWR

DC/DC Input

LI supplies the current for the charge pump of the DC/DC converter.

- LI tied directly to VCC : the DC/DC converter must be configured in regulator

mode.

- LI tied to VCC through an external 10µH coil : the DC/DC converter can be

configured either in regulator or in pump mode.

CVCC

9

9

PWR

Card Supply Voltage

CVCC is the ouput of internal DC/DC converter which supplies the Smart Card

Interface. It must be connected to an external decoupling capacitor of 10 µF with

the lowest ESR as this parameter influences on the CVCC noise

Table 1. Pin Description (Continued)

Port

Internal

Power

Supply

ESD

I/O

Reset

Level

Alt