This document contains code snippets and explanations for basic experiments using 8051 assembly language code. 1) It includes code to move and exchange data within RAM and between RAM and external memory. 2) Code is provided to perform arithmetic operations like addition, subtraction, multiplication, and division on 8-bit numbers. 3) Logical operations like AND, OR, XOR, and bit shifts are demonstrated. 4) Conversions between binary, BCD, and ASCII representations are shown. 5) Additional code snippets sort arrays, search for a number, count bits, and toggle an output pin with a delay.

1. Basic Experiments
(Using ALP code)

2. Data Movement
a) Move a block of data within internal RAM
8051 ALP code
ORG 00H
MOV R1,#50H
MOV RO,#60H
MOV R3,#0AH
LOOP:MOV A,@R1
MOV @R0,A
INC R1
INC R0
DJNZ R3,LOOP
HERE:SJMP HERE
END
Result : Enter 10 numbers in the memory location d:0x59.Run
the program and see the result in memory location d:0x60 to
0x69
Sample Run:
Before execution: d:0x50 = 45 25 60 25 60 55 44 12 41 58
After execution : d:0x60 = 45 25 60 25 60 55 44 12 41 58

3. b) Exchange a block of data between internal RAM and
External memory
8051 ALP code
ORG 00H
MOV R0,#50H //SOURCE ADDRESS
MOV DPTR,#0150H //DESTINATION ADDRESS
MOV R3,#05H //COUNT
BACK:MOV A,@R0
MOV R2,A
MOVX A,@DPTR
MOV @R0,A
XCH A,R2
MOVX @DPTR,A
INC R0
INC DPTR
DJNZ R3,BACK
HERE:SJMP HERE
END
Sample Run:
Before execution: d:0x50 = 45 58 52 92 25
After execution : x:0x0150 = 45 58 52 92 25

4. Arithmetic Operation :
a)Evaluate simple arithmetic expression such as y=((5*2)-(4-1))/3)%2
8051 ALP code
ORG 00H
MOV A,#4
MOV R1,#1
ADD A,R1
MOV R1,A
MOV B,#05H
MOV A,#02H
MUL AB
SUBB A,R1
MOV B,#03H
DIV AB
MOV 30H,A
HERE:SJMP HERE
END
Sample Run:
Before execution: d:0x30 = 00
After execution : d:0x30 = 01

5. b)Addition of three 8-bit BCD numbers and obtain result in BCD form
8051 ALP code
ORG 00H
START:MOV R0,#02H
MOV R2,#00H
MOV R1,#50H
MOV A,@R1
INC R1
UP : ADD A,@R1
DA A
JNC NEXT
INC R2
NEXT : INC R1
DJNZ R0,UP
MOV O3H,A
HERE:SJMP HERE
END
Sample Run:
Before execution: d:0x50 = 05 06 04
After execution : d:0x02 = 00 15

6. Logical Operation :
a)Evaluate logical expression Y=a&&b||c^!d where a,b,c and d
are 8-bit data
8051 ALP code
ORG 00H
MOV R0,40H
MOV A,41H
ANL A,R0
MOV B,A
MOV R0,42H
MOV A,43H
CPL A
XRL A,R0
ORL A,B
MOV 44H,A
HERE:SJMP HERE
END
Sample Run:
Before execution: d:0x40 = 45 56 14 85
After execution : d:0x44 = 6E

7. b)Rotation or Shift operation on 16 bit data
8051 ALP code
ORG 00H
CLR C
MOV A,41H
RLC A
MOV B,A
MOV A,40H
RLC A
MOV 40H,A
MOV A,B
MOV ACC.0,C
MOV 41H,A
HERE:SJMP HERE
END
Sample Run:
Before execution: d:0x40 = 45 56
After execution : d:0x44 = 8A A C

8. Code Conversions :
a)(1)Two digit packed BCD to unpacked BCD
8051 ALP code
ORG 00H
MOV A,40H
MOV B,A
ANL A,#0F0H
SWAP A
MOV 41H,A
MOV A,B
ANL A,#0FH
MOV 42H,A
HERE:SJMP HERE
END
Sample Run:
Before execution: d:0x40 = 32
After execution : d:0x41 = 03 02

9. a)(2)Two digit unpacked BCD to packed BCD
8051 ALP code
ORG 00H
MOV A,40H
SAWP A
ORL A,41H
MOV 42H,A
HERE:SJMP HERE
END
Sample Run:
Before execution: d:0x40 = 03 02
After execution : d:0x44 = 32

10. b)(1) BCD to Binary Conversion
8051 ALP code
ORG 00H
MOV DPTR,#40H
MOVX A,@DPTR
ANL A,#0F0H
SWAP A
MOV B,#0AH
MUL AB
MOV R1,A
MOVX A,@DPTR
ANL A,0FH
ADD A,R1
INC DPTR
MOVX @DPTR,A
HERE:SJMP HERE
END
Sample Run:
Before execution: X:0x0040 = 45(Decimal/BCD)
After execution : X:0x0041 = 2D(Hex/Binary value)

11. b)(2) Binary to BCD Conversion
8051 ALP code
ORG 00H
MOV DPTR,#9000H
MOVX A,@DPTR
MOV B,#10
DIV AB
INC DPTR
XCH A,B
MOVX @DPTR,A
XCH A,B
MOV B,#10
DIV AB
INC DPTR
MOVX A,@DPTR
HERE:SJMP HERE
END
Sample Run:
Before execution: X:0x9000 = FF(Hex/Binary value)
After execution : X:0x9001 = 05(BCD Value)lower digit first
X:0x9002H = 05(BCD Value)
X:0x9002H = 02(BCD Value)Higher digit first

12. c)(1) Two digit packed BCD to ASCII
8051 ALP code
ORG 00H
MOV R1,#50H
MOV A,@R1
MOV R2,A
SWAP A
ANL A,#OFH
ORL A,#30H
INC R1
MOV @R1,A
MOV A,R2
ANL A,#0FH
ORL A,#30H
INC R1
MOV @R1,A
HERE:SJMP HERE
END
Sample Run:
Before execution: d:0x50 = 48
After execution : d:0x51 = 34 38

13. b)(2) Binary to BCD Conversion
8051 ALP code
ORG 00H
CLR C
MOV A,40H
SUBB A,#30H
SWAP A
MOV B,A
CLR C
MOV A,41H
SUBB A,#30H
ADD A,B
MOV 42H,A
HERE:SJMP HERE
END
Sample Run:
Before execution: d:0x40 = 34 38
After execution : d:0x42 = 48

14. Program to search a given 8bit number in an array of N numbers.
8051 ALP code
ORG 00H
MOV R0,#40H
MOV R1,#0AH
MOV A,#76H
BACK:MOV B,@RO
CJNE A,B,NEXT
MOV A,OFFH
SJMP LAST
NEXT:INC R0
DJNZ R1,BACK
MOV A,#0AAH
LAST:MOV 78H,B
HERE:SJMP HERE
END
Sample Run:
Before execution: d:0x40 = 45 58 39 45 89 45 22 69 76 33
Reg B = 76
After execution : d:0x78 = FF

15. a)To sort an array of an 6 byte of data in ascending order.
8051 ALP code
ORG 00H
MOV R0,#50
L1:MOV DPTR,#9000H
MOV A,R0
MOV R1,A
L2:MOVX A,@DPTR
MOV B,A
INC DPTR
MOVX A,@DPTR
CLR C
MOV R2,A
SUBB A,B
JNC NOEXCHG
MOV A,B
MOVX @DPTR,A
DEC DPL
MOV A,R2
MOVX @DPTR,A
INC DPTR
NOEXCHG:DJNZ R1,L2 Sample Run:
DJNZ RO,L1 Before execution:X:0x9000 = 45 58 39 45 89 95
HERE:SJMP HERE After execution :X:0x9000 = 39 45 45 58 89 95
END

16. a)To sort an array of an 6 byte of data in descending order.
8051 ALP code
ORG 00H
MOV R0,#50
L1:MOV DPTR,#9000H
MOV A,R0
MOV R1,A
L2:MOVX A,@DPTR
MOV B,A
INC DPTR
MOVX A,@DPTR
CLR C
MOV R2,A
SUBB A,B
JC NOEXCHG
MOV A,B
MOVX @DPTR,A
DEC DPL
MOV A,R0
MOVX @DPTR,A
INC DPTR
NOEXCHG:DJNZ R1,L2 Sample Run:
DJNZ RO,L1 Before execution:X:0x9000 = 45 58 39 45 89 95
HERE:SJMP HERE After execution :X:0x9000 = 95 89 58 45 45 39
END

17. Program to count the number of ones and zeros in the data
saved in two consecutive memory location.
8051 ALP code
ORG 00H
MOV R0,#00H
MOV R1,#00H
MOV R2,#08H
MOV A,#0F0H
LOOP3:CLR C
RLC A
JC LOOP1
INC R0
SJMP LOOP2
LOOP1:INC R1
LOOP2:DJNZ R2,LOOP3
HERE:SJMP HERE
END
Sample Run:
Input for execution : Ri = OFOH
Output of execution : R0 = 04
R1 = 04

18. Program to toggle a particular bit in the internal RAM with the
delay of N ms given the clock frequency f MHz with the use of
delay subroutine.
8051 ALP code
ORG 00H
AGAIN:
SETB P1.2
ACALL DELAY
CLR P1.2
ACALL DELAY
SJMP AGAIN
DELAY:MOV TMOD,#10H
MOV TL1,#0B0H
MOV TH1,3CH
SETB TR1
BACK:
JNB TF1,BACK
CLR TR1
CLR TF1
RET
END
Result : Run the program and observe the toggling of P1.2 bit.