;VIET CT TAO SONG VUONG 1HZ TREN CHAN P1.0 DUFNG TIMER0 MODE ORG 2000H MOV TMOD,#02H LOOP: MOV R7,#20 LAP1: MOV R6,#100 LAP: MOV TH0,#-250 SETB TR0 JNB TF0,$ CLR TF0 CLR TR0 DJNZ R6,LAP DJNZ R7,LAP1 CPL P1.0 SJMP LOOP END