Question

Assume that a switch is connected to pin P1.4 and a value stored in R5. Write a program that checks that status of the switch continuously, if the switch is ON decrement the value of R5 and send the value to P2 and the complement to P3. The program stops when the value of R5 reaches zero. 3. Write a program to add contents of 5 memory locations from location 40H onwards. The program then stores the result in R6 and sends it P2. If the final carry, after adding all of the values, equals to1 then set the bit 2AH in the memory 4. Write a program that reads a number from 8 switches connected to P2 then counts number of 1's in that number to display it as a binary number on 8 LEDs connected to 5. P3. Include a subroutine in your program to do the task of counting the 1's.

Answer 1

1)
AGAIN: JB P1.4 OVER // IF P1.4 IS 0 JUMP TO OVER
DJNZ R5 AGAIN // JUMP TO AGAIN IF R5 NOT EQUAL TO 0
  
OVER : DEC R5 // DECREMENT R5
MOV A,R5
MOV P2,A
CPL A // COMPLEMENT A
MOV P3,A AGAIN

2)
BACK: MOV RO #40H // RAM STARTING FROM 40H LOCATION
mov R1 #05 // 5 ITERATIONS
CLR A
ADD A, @RO // ADDITION
INC R0
DJNZ R1,
MOV R6,A // SAVE SUM INTO R6
MOV P2,A
JC JUMP
END
JUMP : SETB 2AH // SETTING

*Untitled Document (/Desktop) - gedit En 4D) 1:30 AM Open ▼ Save 1) AGAIN: JB P1.4 OVER IF P1.4 IS JUMP TO OVER DJNZ R5 AGAIN // JUMP TO AGAIN IF R5 NOT EQUAL TO θ // DECREMENT R!5 // COMPLEMENT A OVERDEC RS MOV A,R5 MOV P2,A CPL A MOV P3,A AGAIN PC 2) BACK: MOV RO #49H RAM STARTING FROM 40H LOCATION // 5 ITERATİONS mov R1 #05 CLR A ADD A, RO // ADDITION DJNZ R1, MOV R6,A MOV P2,A C JUMP END SAVE SUM INTO R6 UMP SETB 2AH I SETTING Plain TextTab Width:8 Ln 30, Col 1 INS