ORG 0000H MAIN:; Bat dau chuong trinh chinh CALL CTA;Goi chuong trinh con sang dan tu tren xuong duoi CALL CTB;Goi chuong trinh con sang dan tu duoi len tren JMP MAIN ;-----------chuong trinh con sang dan tu tren xuong duoi-------------------------- CTA: MOV A,#00H;Thanh ghi A la 00000000 LAP:;Nhan cua vong lap SETB C;Thit lap co nho C len 1 RLC A;Quay trai co C co nho MOV P2,A;Dua gia tri vao P2 CALL DELAY;Tao thoi gian tre de thay hieu ung CJNE A,#0FFH,LAP;Kiem tra neu chua bang 11111111 thi nhay den nhan LAP RET ;-------------chuong trinh con sang dan tu duoi len tren------------------------- CTB: MOV A,#00H; dua gia tri 00000000 vao thanh ghi tich luy A LAP1: ; nhan vong lap SETB C ; Thiet lap co nho C len 1 RRC A ; quay phai thanh ghi A co co nho MOV P2,A ; chuyen gia tri thanh ghi A vua quay xuat ra Port 2 CALL DELAY;goi chuong trinh tre de thay hieu ung led CJNE A,#0FFH,LAP1;Kiem tra thanh ghi A da bang 11111111 chua, neu chua bang thin hay den LAP1 RET ;----Chuong trinh tao thoi gian tre----- DELAY: MOV R0,#200 LOOP: MOV R1,#210 LOOP1: NOP DJNZ R1,LOOP1 DJNZ R0,LOOP RET END