Question

Lab Activity 2 Test the 8051's ports for input operation as follows: A) Connect each bit of Pl (P1.0-P1.7) of the 8051 to DIP switches of your development kit. Connect each bit of P2 (P2.0-P2.7) of the 8051 to LED indicators of your development kit. B) Write and run a program to get data from Pl and send it to P2. Any change of status of the switches connected to P1 will be instantly reflected on LEDS connected to P2. C) The testing program could look like this. MOV A,#0FF ;A=FFH make Pl an input port HERE: MOV A,PI get data from P1 send it to P2 MOV P1,A MOV P2,A keep doing this SJMP HERE Note: You may need to insert a delay in the appropriate place, so you will be able to observe the proper running of your program.

Answer 1

MOV A, 0xFF ;A = 0xFF, Move data 0xFF to Accumulator
MOV P1, A : Move data from Accumulator into Port-1
HERE:
MOV A, P1 : Read Data from Port-1
MOV P2, A : Send data from Port- to Port-2

MOV R6,0xC8 ; Load R6 with 200 decimal Value for 200 msec delay
LOOP:
ACALL DELAY
DJNZ R6,LOOP

SJMP HERE ; Keep on doing, infinite loop

DELAY: ; Delay for 1 msec., TL0 and TH0 are computed using Crystal = 11.0592 MHz
MOV TMOD,0x1B ; Sets Timer 0 to MODE1 (16 bit timer). Timer 1 is not used
MOV TH0, 0xFCH ; Loads TH0 register with FCH
MOV TL0, 0x18H ; LOads TL0 register with 18H
SETB TR0 ; Starts the Timer 0
HERE: JNB TF0,HERE ; Loops here until TF0 is set
CLR TR0 ; Stops Timer 0
CLR TF0 ; Clears TF0 flag
RET