1

PLCC

7

8

9

10

11

12

13

14

15

16

17

39

38

37

36

35

34

33

32

31

30

29

P1.5

P1.6

P1.7

RST

(RXD) P3.0

NC

(TXD) P3.1

(INT0) P3.2

(INT1) P3.3

(T0) P3.4

(T1) P3.5

P0.4 (AD4)

P0.5 (AD5)

P0.6 (AD6)

P0.7 (AD7)

EA/VPP

NC

ALE/PROG

PSEN

P2.7 (A15)

P2.6 (A14)

P2.5 (A13)

Features

Description

The AT87F55WD is a low-power, high-performance CMOS 8-bit microcomputer with

20K bytes of QuickFlash one-time programmable (OTP) read only memory and 256

bytes of RAM. The device is manufactured using Atmel’s high-density nonvolatile

memory technology and is compatible with the industry standard 80C51 and 80C52

instruction set and pinout. The on-chip QuickFlash allows the program memory to be

user programmed by a conventional nonvolatile memory programmer. By combining a

versatile 8-bit CPU with QuickFlash on a monolithic chip, the Atmel AT87F55WD is a

powerful microcomputer which provides a highly-flexible and cost-effective solution to

many embedded control applications.

Rev. 1918A–08/00

8-bit

Microcontroller

with 20K Bytes

QuickFlash™

AT87F55WD

PDIP

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

40

39

38

37

36

35

34

33

32

31

30

29

28

27

26

25

24

23

22

21

(T2) P1.0

(T2EX) P1.1

P1.2

P1.3

P1.4

P1.5

P1.6

P1.7

RST

(RXD) P3.0

(TXD) P3.1

(INT0) P3.2

(INT1) P3.3

(T0) P3.4

(T1) P3.5

(WR) P3.6

(RD) P3.7

XTAL2

XTAL1

GND

VCC

P0.0 (AD0)

P0.1 (AD1)

P0.2 (AD2)

P0.3 (AD3)

P0.4 (AD4)

P0.5 (AD5)

P0.6 (AD6)

P0.7 (AD7)

EA/VPP

ALE/PROG

PSEN

P2.7 (A15)

P2.6 (A14)

P2.5 (A13)

P2.4 (A12)

P2.3 (A11)

P2.2 (A10)

P2.1 (A9)

P2.0 (A8)

Pin Configurations

TQFP

1

2

3

4

5

6

7

8

9

10

11

33

32

31

30

29

28

27

26

25

24

23

P1.5

P1.6

P1.7

RST

(RXD) P3.0

NC

(TXD) P3.1

(INT0) P3.2

(INT1) P3.3

(T0) P3.4

(T1) P3.5

P0.4 (AD4)

P0.5 (AD5)

P0.6 (AD6)

P0.7 (AD7)

EA/VPP

NC

ALE/PROG

PSEN

P2.7 (A15)

P2.6 (A14)

P2.5 (A13)