4-29

PQFP/TQFP

23

1

I NDEX

CORNER

34

42

43

40

41

6

5

4

44

3

2

26

25

28

27

24

18

19

20

21

22

P1.7

P1.6

P1.5

NC

7

8

9

10

11

12

13

14

15

16

17

29

30

39

38

37

36

35

33

32

31

NC

PSEN

ALE/PR OG

EA/VPP

(RX D )

P 3.0

P0.7

( A D7)

P2.6

(A14)

P0.6

( A D6)

P0.5

( A D5)

P0.4

( A D4)

()

P 3 . 2

INT0

(TX D )

P 3.1

(T1)

P 3 .5

()

P 3 . 3

INT1

(T0)

P 3 .4

P2.7

(A15)

RST

P2.5

(A13)

Features

– Endurance: 1,000 Write/Erase Cycles

Description

The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K

bytes of Flash Programmable and Erasable Read Only Memory (PEROM). The

device is manufactured using Atmel’s high density nonvolatile memory technology

and is compatible with the industry standard MCS-51™ instruction set and pinout. The

on-chip Flash allows the program memory to be reprogrammed in-system or by a con-

ventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with

Flash on a monolithic chip, the Atmel AT89C51 is a powerful microcomputer which

provides a highly flexible and cost effective solution to many embedded control appli-

cations.

PDIP

P1.0

P1.1

P0.0

( A D0)

P1.2

()

P 3 . 2

INT0

ALE/PR OG

()

P 3 . 7

RD

P2.3

(A11)

(TX D )

P 3.1

EA/VPP

()

P 3 . 6

WR

P2.4

(A12)

(RX D )

P 3.0

P0.7

( A D7)

(T1)

P 3 .5

P2.6

(A14)

RST

P0.6

( A D6)

P1.7

P0.5

( A D5)

P1.6

P0.4

( A D4)

P1.5

P0.3

( A D3)

P1.4

P0.2

( A D2)

P1.3

P0.1

( A D1)

()

P 3 . 3

INT1

PSEN

XTAL2

P 2.2

( A10)

(T0)

P 3 .4

P2.7

(A15)

XTAL1

P 2.1

( A9)

GND

P 2.0

( A 8 )

P2.5

(A13)

20

19

18

17

16

15

1

2

3

4

5

6

7

8

9

10

11

12

13

14

21

22

23

24

25

26

40

39

38

37

36

35

34

33

32

31

30

29

28

27

0265F-A–12/97

(continued)

8-Bit

Microcontroller

with 4K Bytes

Flash

AT89C51

Pin Configurations

PLCC

ALE/PR OG

EA/VPP

(RX D ) P 3.0

P0.7 ( A D7)

P2.6 (A14)

P0.6 ( A D6)

P0.5 ( A D5)

P0.4 ( A D4)

PSEN

() P 3 . 2

INT0

(TX D ) P 3.1

(T1) P 3 .5

() P 3 . 3

INT1

(T0) P 3 .4

P2.7 (A15)

23

1

RST

P1.7

P1.6

P1.5

I NDEX

CORNER

NC

P2.5 (A13)

34

NC

42

43

40

41

6

5

44 4

3

2

26

25

28

27

18

19

20

24

21

22

7

8

9

10

11

12

13

14

15

16

17

29

30

39

38

37

36

35

33

32

31