 2000 Infineon Technologies Corp. • Optoelectronics Division • San Jose, CA

Appnote 49

www.infineon.com/opto • 1-888-Infineon (1-888-463-4636)

OSRAM Opto Semiconductors GmbH & Co. OHG • Regensburg, Germany

www.osram-os.com • +49-941-202-7178

5

May 31, 2000-14

Program listing

UDISP

’PD 2435 Display PROGRAM’

1

$TITLE (‘PD 2435 DISPLAY PROGRAM’)

2

$MOD515

3

$NOSYMBOLS

4

....

5

CSEG

6

$DEBUG

7

8

0000

9

ORG

00H

10

0000 02000C

11

LJMP

BEGIN

;Jump on reset

12

13

;

14

;

15

;

16

;

17

;

18

0003

19

ORG

03H

20

0003 C0E0

21

PUSH

ACC

0005 D2D5

22

SETB

F0

;Set flag for external interrupt

0007 D0E0

23

POP

ACC

0009 C289

24

CLR

IE0

000B 32

25

RETI

26

27

;

28

;

29

;

30

000C D282

31

BEGIN:

SETB

P3.2

;Set bit for INT0

000E 758110

32

MOV

SP,#10H

0011 75D800

33

MOV

ADCON, #00H

;Select analog channel 0

34

0014 C2D5

35

OPTS:

CLR

F0

;Clear flag 0

0016 7800

36

MOV

R3,#00H

;Character pointer in the message

0018 79FF

37

MOV

R1,#0FFH

;R1 used as a flag

001A 90F000

38

MOV

DPTR,#0F000H

;Control register of all displays

001D 7403

39

MOV

A,#03H

;Control word for display

001F F0

40

MOVX

@DPTR,A

0020 9000C2

41

MOV

DPTR,#(TEXT-1)

;Beginning of the text

0023 7820

42

MOV

R0,#20H

;Internal RAM location

0025 7D65

43

MOV

R5,#101

;A count for 101 characters

0027 7420

44

MOV

A,#20H

;ASCII for space

0029 F6

45

BLANK:

MOV

@R0,A

;Fill all locations with blank

002A 08

46

INC

R0

002B DDFC

47

DJNZ

R5, BLANK

48

002D 12006C

49

SHIF:

CALL

NEXTC

;Read the next character

0030 20D501

50

JB

F0,TEMP

;Check if the interrupt was raised

0033 0B

51

INC

R3

;If no interrupt

0034 7D65

52

TEMP:

MOV

R5,#101

;Character count in message

0036 7820

53

MOV

R0,#20H

;RAM location 20H

0038 20D506

54

JB

F0,REV0

003B C6

55

SHFT:

XCH

A,@R0

;If no interrupt

003C 08

56

INC

R0

;Add the character

003D DDFC

57

DJNZ

R5,SHFT

;To the top of the RAM buffer

003F 0158

58

AJMP

CONT0

0041 7421

59

REV0:

MOV

A,#21H

;If there is no interrupt

0043 2B

60

ADD

A,R3

;Offset for the RAM buffer

This is the interrupt subroutine for INTO. This is used to set a flag

which then indicates that the message needs to be rolled back.

MAIN PROGRAM