the o/p of moc7811 is fed to 89c52 on p3.4
also four 7-seg displays are interfaced to port 0 and port 2 of 89c52 through four bcd to 7-seg decoder ic7447.
pls have a look at the program and suggest any modifications if required


org 0000H
LJMP main
org 0200H

main:
MOV TMOD,#15H ;SET TIMER0 AS COUNTER,TIMER1 TIMER
SETB P3.4
MOV TL0,#00H
MOV TH0,#00H
MOV R0,#28 ; TO SET THE TIMER ON FOR 1 SECOND
again:
MOV TL1,#00H
MOV TH1,#00H
SETB TR0
SETB TR1
back:
JNB TF1,back
CLR TF1
CLR TR1
DJNZ R0,again
MOV A,TL0
MOV B,3CH ;SINCE ABOVE PROGRAM WILL COUNT NO
MUL AB ;OF REV IN 1SEC
ADD A,#00H ;TO CALCULATE REV PER MINUTE
DA A ;MULTIPLY WITH 60SEC THAT IS 3CH
MOV P0,A
MOV A,#00H
ADDC A,B
DA A
MOV P2,A
LJMP main
end

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