3

AT83C21GC

4247AS–SCR–04/03

Pin Description

Figure 2. 24-pin SSOP Pinout

P1.1/CC8

P1.4/CCLK

P1.0/CIO

RST

P1.5/CRST

1

P1.3/CC4

P1.2/CPRES

XTAL1

P3.3/INT1/OE

P3.2/INT0

P3.4/T0

P3.5/CIO1/T1

LI

C

V

CC

CVSS

E

V

CC

VSS

P3.0/RxD

P3.1/TxD

2

3

4

5

6

7

8

9

10

11

12

24

23

22

21

20

19

18

17

16

15

14

13

P3.6/CCLK1/LED0

XTAL2

P3.7/CRST1/LED1

D

SSOP24

Table 1. Port Signal Description

Port

Signal

Name

Internal

Power

Supply

ESD

Type

Description

P1.0

CIO

4 kV

I/O

Smart Card Interface Function

Card I/O – Pull-up medium is lower than 20K

Ω

P1.1

CC8

4 kV

I/O

Smart Card Interface Function

Card contact 8 – Pull-up medium must be less than 20K

Ω

P1.2

CPRES

4 kV

I

Smart Card Interface Function

Card presence

P1.3

CC4

4 kV

I/O

Smart Card Interface Function

Card contact 4 – Pull-up medium must be less than 20K

Ω

P1.4

CCLK

4 kV

O

Smart Card Interface Function

Card clock

P1.5

CRST

4 kV

O

Smart Card Interface Function

Card reset – Pull-up medium must be less than 20K

Ω

P3.0

RxD

I

UART Function

Receive data input

P3.1

TxD

O

UART Function

Transmit data output.

P3.2

INT0

I/O

Input/Output Function

P3.2 is a bi-directional I/O port with internal pull-ups.

P3.3

INT1

I/O

Input/Output Function

P3.3 is a bi-directional I/O port with internal pull-ups.

P3.4

I/O

Input/Output Function

P3.4 is a bi-directional I/O port with internal pull-ups.

P3.5

CIO1

I/O

Alternate Card Function

Card I/O: Pull-up medium must be less than 20K