The 8051 Microcontroller and Embedded

Department of Computer Scien

ce and Information Engineering

National Cheng Kung University, TAIWAN

HANEL

PROGRAMMING THE 82558255 Features

8255 Chip

21

20

22

19

23

18

24

17

25

16

26

15

27

14

28

13

29

12

30

11

31

10

32

9

33

8

34

7

35

6

36

5

37

(^8255) A
4
38
3
39
2
40
1
PA3PA2PA1PA0RDCS GNDA1 A0PC7PC6PC5PC4PC0PC1PC2PC3PB0PB1PB2
PA4PA5PA6PA7WRRESETD0D2D2D3D4D5D6D7VCCPB7PB6PB5PB4PB3
8255 is a 40-pin DIP chip