Timers programming in Assembly level language for 8051 Microcontroller

Timers programming in Assembly level language for 8051 Microcontroller

Write ALP to generate square wave of 50% duty cycle on P2.3. Use Timer0 to generate time delay. Mode 1

Assembly Code:

ORG 0000H
MOV TMOD,#01H
HERE: MOV TL0,#0F2H
MOV TH0,#0FFH
CPL P2.3
ACALL DELAY
SJMP HERE
DELAY: SETB TR0
AGAIN: JNB TF0,AGAIN
CLR TR0
CLR TF0
RET
END

Write ALP to generate square wave of 50% duty cycle on P2.3. Use Timer0 to generate time delay. Mode 2

Assembly Code:

     ORG 0000H
        MOV TMOD,#02H   // Timer 0, Mode 2
        MOV TL0,#0F0H
        MOV TH0,#0FH
HERE:   CPL P2.3
        ACALL DELAY
        SJMP HERE
DELAY:  SETB TR0
AGAIN:  JNB TF0,AGAIN
        CLR TF0
        RET
        END

Write ALP to generate square wave of 2kHz frequency on pin P1.1 (Crystal frequency= 11.0592MHz)

Assembly Code:

     ORG 0000H
        MOV TMOD,#01H
HERE:   MOV TL0,#1AH  
        MOV TH0,#0FFH
        CPL P1.1
        ACALL DELAY
        SJMP HERE
DELAY:  SETB TR0
AGAIN:  JNB TF0,AGAIN
        CLR TR0
        CLR TF0
        RET
        END

Write ALP for Counter 1 in mode 2 to count pulses fed into pin T1.

Assembly Code:

ORG 0000H
MOV TMOD,#01100000B //Counter 1, Mode 2
                    //Count External Pulses
MOV TH1, #00H       //Clear TH1
SETB P3.5           //Make T1 pin Input
AGAIN: SETB TR1     //Start the counter
BACK: MOV A,TL1     //Get copy of Count TL1
MOV R7, A           //Store value of count in R7
JNB TF1, BACK       //Keep Counting until counter overflow
CLR TR1             //Stop Counter 1
CLR TF1             //Make TF=0
SJMP AGAIN          //Keep Doing It
END