Write a program in C in which every 2 seconds the LED connec

Write a program in C, in which every 2 seconds, the LED connected to P2.7 is turned on and off four times, while the 8051 is getting data from P1 and sending it to P0 continuously. Make sure the on and off states are 50 ms in duration.

Solution

ORG 0

LJMP MAIN
ORG 23H
LJMP SERIAL ;jump to serial int ISR
ORG 30H
MAIN: MOV P1,#0FFH ;make P1 an input port
MOV TMOD,#20H ;timer 1, auto reload
MOV TH1,#0FDH ;9600 baud rate
MOV SCON,#50H ;8-bit,1 stop, ren enabled
MOV IE,10010000B ;enable serial int.
SETB TR1 ;start timer 1
BACK: MOV A,P1 ;read data from port 1
MOV P2,A ;send it to P2
SJMP BACK ;stay in loop indefinitely
LJMP MAIN
ORG 000BH ;ISR for Timer 0
CPL P2.7
MOV TL0,#00
MOV TH0,#0DCH
RETI
ORG 30H
;--------main program for initialization
MAIN:MOV TM0D,#00000001B ;Timer 0, Mode 1
MOV TL0,#00
MOV TH0,#0DCH
MOV IE,#82H ;enable Timer 0 interrupt
SETB TR0
HERE:SJMP HERE
END