- Examine the content of A, if 5 ≤ A ≤ 10 then output A to Port 1; if not, output A to Port 2
ORG 0
CJNE A, #5, $+3
JC PORT2
CJNE A, #11, $+3
JNC PORT2
MOV P1, A
SJMP DONE
PORT2: MOV A, P2
DONE: NOP
END
- Assume that a line of ASCII codes is in internal memory beginning at address 08H. This line is terminated with a carriage return code (0DH). Write a program that sends this string to Port 1.
ORG 0
MOV R0, #08H
LOOP:
MOV P1, @R0
INC R0
CJNE @R0, #0DH, LOOP
END
- Write a program to write 40H to internal RAM from location 30H to location 36H.
ORG 0
MOV R0, #30H
LOOP:
MOV @R0, #40H
INC R0
CJNE R0, #37H, LOOP
END
- Assume that a string of ASCII codes is in internal memory beginning from address 08H to 0DH. Write a program that sends this string to Port 1.
ORG 0
MOV R0, #08H
MOV R7, #6
LOOP:
MOV P1, @R0
INC R0
DJNZ R7, LOOP
END
- Write a program to write 40H to internal RAM from location 30H to location 36H.
ORG 0000H
MOV R7, #7
MOV R0, #30H
LOOP:
MOV @R0, #40H
INC R0
DJNZ R7, LOOP
END
- Write a program to clear ACC, then add 3 to the accumulator ten times.
ORG 0
CLR A
MOV R7, #10
LOOP:
ADD A, #3
DJNZ R7, LOOP
END
- Write a program to copy a block of 10 bytes from RAM location starting at 37h to RAM location starting at 59h.
ORG 0000H
MOV R7, #10 ;COUNTER
MOV R0, #37H ;SOURCE POINTER
MOV R1, #59H ;DEST POINTER
LOOP:
MOV A, @R0
MOV @R1, A
INC R1
INC R0
DJNZ R7, LOOP
END
- Given a 20-byte string in internal RAM, starting at address 40H. Write a program that output even numbers to Port 2.
ORG 0000H
MOV R7, #20
MOV R0, #40H
LOOP:
MOV A, @R0
RRC A
JC ODD_NUM
MOV P2, @R0
ODD_NUM:
INC R0
DJNZ R7, LOOP
END
- Given a 20-byte string in external RAM, starting at address 4000H. Write a program that output odd numbers to Port 2
ORG 0000H
MOV R7, #20
MOV DPTR, #4000H
LOOP:
MOVX A, @DPTR
JNB ACC.0, EVEN_NUM
MOV P2, A
EVEN_NUM:
INC DPTR
DJNZ R7, LOOP
END
- Given a 20-byte string in internal RAM, starting at address 40H. Write a program that output even numbers to Port 2 and odd numbers to Port 1
ORG 0000H
MOV R0, #40H
MOV R7, #20
LOOP:
MOV A, @R0
JNB ACC.0, EVEN_NUM
MOV P1, @R0
SJMP NEXT
EVEN_NUM:
MOV P2, @R0
NEXT: INC R0
DJNZ R7, LOOP
END
- Given a 100-byte signed number string in external RAM at address starting from 0100H. Write a program that sends positive numbers to Port 1 and negative numbers to Port 2.
HINT :
- A positive number has MSB = 0.
- A negative number has MSB = 1.
- Use JB/JNB instruction
ORG 0000H
MOV R7, #100
MOV DPTR, #0100H
LOOP:
MOVX A, @DPTR
JB ACC.7 NEGATIVE
MOV P1, A
SJMP NEXT
NEGATIVE:
MOV P2, A
NEXT:
INC DPTR
DJNZ R7, LOOP
END
LOOP:
MOV C, P1.0
JNB P1.1, SKIP
CPL C
SKIP:
MOV P1.2, C
SJMP LOOP
- Given a packed-BCD number in location 33H of internal RAM. Write a program that calculate the square of high decade of this number, and store the result in internal RAM at address 34H
ORG 0000H
MOV A, 33H
SWAP A
ANL A, #0FH
MOV DPTR, #TABLE
MOVC A, @A+DPTR
MOV 34H, A
TABLE:
DB 0, 1, 4, 9, 16, 25, 36, 49, 64, 81
END
- Given a packed-BCD number in location 34H of internal RAM. Write a program that displays the low decade of this number on the common-anode 7-seg LED connected to Port 2 (schematic).
| D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | ||
|---|---|---|---|---|---|---|---|---|---|
| 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 40H |
| 1 | 0 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 79H |
| 2 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 24H |
| 3 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 30H |
| 4 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 19H |
| 5 | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 12H |
| 6 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 02H |
| 7 | 0 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 78H |
| 8 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 00H |
| 9 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 10H |
ORG 0000H
MOV 34H, #25H ;CHANGEBLE
MOV A, 34H
ANL A, #0FH
MOV DPTR, #TABLE
MOVC A, @A+DPTR
MOV P2, A
SJMP DONE
TABLE:
DB 40H, 79H, 24H, 30H, 19H
DB 12H, 02H, 78H, 00H, 10H
DONE:
NOP
END
- A 4-bit DIP switch and a common-anode 7-segment LED are connected to an 8051 as shown in the following figure. Write a program that continually reads a 4-bit code from the DIP switch and updates the LEDs to display the appropriate hexadecimal character. For example, if the code 1100B is read, the hexadecimal character “C” should appear, thus, segments a through g respectively should be ON, OFF, OFF, ON, ON, ON, and OFF. Note that setting an 8051 port pin to “1” turns the corresponding segment “ON”.
| DP | G | F | E | D | C | B | A | ||
|---|---|---|---|---|---|---|---|---|---|
| 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 3FH |
| 1 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 06H |
| 2 | 0 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 5BH |
| 3 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 4FH |
| 4 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | 0 | 66H |
| 5 | 0 | 1 | 1 | 0 | 1 | 1 | 0 | 1 | 6DH |
| 6 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 7DH |
| 7 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 07H |
| 8 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 7FH |
| 9 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 6FH |
| A | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 77H |
| B | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 7CH |
| C | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 39H |
| D | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 0 | 5EH |
| E | 0 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 79H |
| F | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 71H |
ORG 0000H
MOV P1, #0
MOV A, P3
ANL A, #0FH
MOV DPTR, #TABLE
MOVC A, @A+DPTR
MOV P1, A
TABLE:
DB 3FH, 06H, 5BH, 4FH, 66H, 6DH, 7DH, 07H
DB 7FH, 77H, 7CH, 39H, 5EH, 79H, 71H
END
- Assume that there are 2 switches connected to P1.0 and P1.1 (active low). Write a program to get the status of these switches every 1 minute and calculates as follow.
| P1.1 | P1.0 | CALCULATION |
|---|---|---|
| 0 | 0 | Rotate right 1 bit Port 2 |
| 0 | 1 | Rotate left 1 bit Port 2 |
| 1 | 0 | Complement Port 2 |
| 1 | 1 | Swap Port 2 |
ORG 0000H
MOV DPTR, #JMP_TABLE
LOOP:
MOV A, P1
ANL A, #03H
RL A
JMP @A+DPTR
JMP_TABLE:
AJMP CASE0
AJMP CASE1
AJMP CASE2
AJMP CASE3
CASE0:
MOV A, P2
RR A
SJMP CONT
CASE1:
MOV A, P2
RL A
SJMP CONT
CASE2:
MOV A, P2
CPL A
SJMP CONT
CASE3:
MOV A, P2
SWAP A
CONT:
MOV P2, A
ACALL DELAY1M
SJMP LOOP
DELAY1M:
MOV R4, #2
LP3:MOV R5, #240
LP2:MOV R6, #250
LP1:MOV R7, #250
DJNZ R7, $
DJNZ R6, LP1
DJNZ R5, LP2
DJNZ R4, LP3
RET
END
- Assume that there are 4 switches connected to P1.0, P1.1, P1.2, P1.3 (active low) and 1 LED connected to P1.7 (active low). Write a program to get the status of these switches and calculates as follow.
| P1.1 | P1.0 | CALCULATION |
|---|---|---|
| 0 | 0 | F=NOT(Y) |
| 0 | 1 | F= X AND Y |
| 1 | 0 | F = X OR Y |
| 1 | 1 | F= X XOR Y |
Note X and Y are data from P1.2 and P1.3, respectively; Output F to P1.7
ORG 0000H
MOV DPTR, #JMP_TABLE
LOOP:
MOV A, P1
ANL A, #0FH
RL A
JMP @A+DPTR
JMP_TABLE:
AJMP CASE_0
AJMP CASE_1
AJMP CASE_2
AJMP CASE_3
CASE_0:
MOV C, P1.3
CPL C
SJMP CONT
CASE_1:
MOV C, P1.3
ANL C, P1.2
SJMP CONT
CASE_2:
MOV C, P1.3
ORL C, P1.2
SJMP CONT
CASE_3:
MOV C, P1.3
JC P1.2, COMPLEMENT
SJMP CONT
COMPLEMENT:
CPL C
CONT:
MOV P1.7, C
SJMP LOOP
END