APPLICATION EXAMPLES

+5V GND

VeeCl"VDD VssI"

2

~ XTAL 1

~ 3

1 XTAL 2

f----! RESET

EA8049 8048

-=58748

NC - ss 8035' 8039'

1

INPUTST1

{::=!-39TO

INT

ALE PSEN PROG WR RD

118

'EA = 5V FOR 8035/8039

P10 27

P11 28

P12 29

P13 30

P14 31

P15 32

P16 33

P17 34 I/O

P20 21

P21 22

P22 23

P23 24

P24 35

P25 36

P26 3L-

P27 38

DBO 12

DB1 13

DB2 14

DB3 15

DB4 16

DB5 17

DB6 18

DB7 19

+5V GND

12

ADO

 

13

AD1

 

14

AD2

 

15

AD3

 

16

AD4

 

17

AD5

8155

18

AD6

256 x 8

19

AD7

 

 

RAM

 

10/M

 

9

RD

 

10. WR

 

11

ALE

 

r

 

ce

 

PAO 2221

PA1

PA2 23

24

PA3 PA4 25 PA5 26 PA6 27 PA7 28

PCO 37 38

PC1 PC2 39

PC3 1 I/O PC4 2

PC5 5

PBO 29 PB1 30 PB2 31 PB3 32 33 PB4PB5 34

PB6 35

CAN BE SUPPLIED BY SYSTEM

-

4 RESET TIMER

TIMER

RESET OR PORT LINE OF 8048

 

OUT

IN

 

 

 

3

 

 

 

TIMER

PBl 36

Both 1/0 and RAM are addressed as data memory

Writing a bit to P27 determines whether RAM or 1/0 is to be accessed

ADDING A DATA MEMORY AND I/O EXPANDER

5-9

Page 120
Image 120
Intel mcs-48 manual =!-39TO, Both 1/0 and RAM are addressed as data memory