Traffic light program in assembly language

   The traffic light program in assembly language uses a 51 single-chip microcomputer, which basically completes the control of two sets of traffic lights to light up alternately. Each intersection has three indicator lights: left turn, straight and pedestrian. The straight light has three colors: red, yellow and green. Non-motor vehicles and cars share the left turn and straight lights. First, the east-west straight green light and pedestrian light are on for 1 minute, the left turn light is on for 30 seconds, and the yellow light is on for 5 seconds (at the same time, the north-south red light is on for 95 seconds), then the east-west red light is on for 95 seconds (at the same time, the north-south straight green light and pedestrian light are on for 1 minute, the left turn light is on for 30 seconds, and the yellow light is on for 5 seconds), then the east-west green light is on, and so on.

   Every time the green light is on, the corresponding pedestrian light is on. 60S/30S/5S/60S/30S/5S
   East-West Road: Green and Pedestrians/Left Turn/Yellow/Red/Red/Red
   North-South Road: Red/Red/Red/Green and Pedestrians/Left Turn/Yellow
   When the pedestrian light is on, there is a voice prompt to let the blind pass. In case of a sudden traffic accident, the light can be turned to red. When an important person passes, the light can be changed to green manually.

ORG 0000H ; Main program entry address
LJMP MAIN ; Jump to the beginning of the main program
ORG 0003H ; External interrupt 0 interrupt program entry address
ORG 000BH ; Timer 0 interrupt program entry address
LJMP T0_INT ; Jump to the interrupt service program
ORG 0013H ; External interrupt 1 interrupt program entry address
MAIN : MOV SP,#50H
MOV IE,#8EH ; CPU interrupt, enable T0 interrupt, T1 interrupt and external interrupt 1 interrupt
MOV TMOD,#51H ; Set T1 to counting mode, T0 to timing mode, and both work in mode 1
MOV TH1,#00H ; Clear T1 counter http://www.5imcu.net/sylyuan.asp
MOV TL1,#00H
SETB TR1 ; Start T1 timer
SETB EX1 ; Enable INT1 interrupt
SETB IT1 ; Select edge trigger mode
MOV DPTR ,#0003H
MOV A, #80H ;Assign initial value to 8255, 8255 works in mode 0
MOVX @DPTR, A
AGAIN: JB P3.1,N0 ;Judge whether to set the initial value of the east-west direction traffic light time, if P3.1 is 1, jump
MOV A,P1
JB P1.7,RED ;Judge whether P1.7 is 1, if it is 1, set the red light time, otherwise set the green light time
MOV R0,#00H ;R0 is cleared
MOV R0,A ;Store the initial time of the east-west direction green light http://www.5imcu.net/sylyuan.asp
MOV R3,A
LCALL DISP1
LCALL DELAY
AJMP AGAIN
RED: MOV A,P1
ANL A,#7FH ;P1.7 is set to 0
MOV R7,#00H ;R7 is cleared
MOV R7,A ;Store the initial time of the red light in the east -west direction
MOV R3,A
LCALL DISP1
LCALL DELAY
AJMP AGAIN
;----------------------------------
N0: SETB TR0 ;Start T0 timer
MOV 76H,R7 ;Store the red light time in 76H N00: MOV A,76H ;Prohibit the east-west direction, allow the north-south direction MOV R3,A MOV DPTR,#0000H ;Set 8255A port, the red light in the east-west direction is on, and the green light in the north-south direction is on MOV A,#0DDH MOVX @DPTR, A N01: JB P2.0,B0 N02: SETB P3.0 CJNE R3,#00H,N01 ;Compare the value in R3 to see if it is 0, if not, jump to the current instruction to execute ;------Program for the yellow light flashing for 5 seconds------ N1: SETB P3.0 MOV R3,#05H MOV DPTR,#0000H ; Set 8255A port, the yellow light in the east-west and north-south directions is on MOV A,#0D4H MOVX @DPTR,A N11: MOV R4,#00H N12: CJNE R4,#7DH,$ ; The yellow light stays on for 0.5 seconds N13: MOV DPTR,#0000H ; Set 8255A port, the yellow light in the north -south direction is off MOV A,#0DDH MOVX @DPTR,A N14: MOV R4,#00H CJNE R4,#7DH,$ ; The yellow light stays off for 0.5 seconds CJNE R3,#00H,N1 ; Exit when the flashing time reaches 5 seconds ;----------------------------------- N2: MOV R7,#00H MOV A,R0 ; East-west traffic is allowed, north-south traffic is prohibited MOV R3,A MOV DPTR,#0000H ; Set port 8255A, green light on in east-west direction, red light on in north-south direction MOV A,#0EBH MOVX @DPTR,A N21: JB P2.0,T03

N22: CJNE R3,#00H,N21
;------Yellow light flashes for 5 seconds program------
N3: MOV R3,#05H
MOV DPTR,#0000H ; Set 8255A port, east-west, north-south direction yellow light is on
MOV A,#0E2H
MOVX @DPTR,A
N31: MOV R4,#00H
CJNE R4,#7DH,$ ;Yellow light stays on for 0.5 seconds
N32: MOV DPTR,#0000H ; Set 8255A port, north-south direction yellow light is off
MOV A,#0EBH
MOVX @DPTR,A
N33: MOV R4,#00H
CJNE R4,#7DH,$ ;Yellow light stays off for 0.5 seconds
CJNE R3,#00H,N3 ; Exit
SJMP N00 when the flashing time reaches 5 seconds
;------Red light running alarm program------
B0: MOV R2,#03H ;Alarm duration is 3 seconds
B01: MOV A,R3
JZ N1 ;If the countdown is completed, no more alarm
CLR P3.0 ;Alarm
CJNE R2,#00H,B01 ;Judge whether 3 seconds are over
SJMP N02
;------1 second delay subroutine-------
N7: RETI
T0_INT:MOV TL0,#9AH ;Send the initial value of 10ms to timer T0
MOV TH0,#0F1H
INC R4
INC R5
CJNE R5,#0FAH,T01 ;Judge whether the delay is enough for one second, if not, call the display subroutine
MOV R5,#00H ;R5 clears
DEC R3 ;Countdown initial value minus one DEC
R2 ;Alarm initial value minus one
T01: ACALL DISP ;Call display subroutine
RETI ;Interrupt return
;------Display subroutine------
DISP: JNB P2.4,T02
DISP1: MOV B,#0AH
MOV A,R3 ;Display conversion of value 2 to 10 in R3
DIV AB
MOV 79H,A
MOV 7AH,B
DIS: MOV A,79H ;Display tens digit
MOV DPTR,#TAB
MOVC A,@A+DPTR
MOV DPTR,#0002H
MOVX @DPTR,A
MOV DPTR,#0001H
MOV A,#0F7H
MOVX @DPTR,A
LCALL DELAY
DS2: MOV A,7AH ;Display ones digit
MOV DPTR,#TAB
MOVC A,@A+DPTR
MOV DPTR,#0002H
MOVX @DPTR,A
MOV DPTR,#0001H
MOV A,#0FBH
MOVX @DPTR,A
RET
;------Traffic flow detection program in the east-west direction------
T03: MOV A,R3
SUBB A,#00H ;If the green light countdown is completed, the traffic flow will no longer be detectedhttp ://www.duankudp.com/
JZ N3
JB P2.0,T03
INC R7
CJNE R7,#64H,E1
MOV R7,#00H ;If the interruption reaches 100 times, clear
E1: SJMP N22
;------Traffic flow display program in the east-west direction------
T02: MOV B,#0AH
MOV A,R7 ;R7 median value 2 to 10 display conversion
DIV AB
MOV 79H,A
MOV 7AH,B
DIS3: MOV A,79H ;Display tens digithttp ://www.duankudp.com/
MOV DPTR,#TAB
MOVC A,@A+DPTR
MOV DPTR,#0002H
MOVX @DPTR,A
MOV DPTR,#0001H
MOV A,#0F7H
MOVX @DPTR,A
LCALL DELAY
DS4: MOV A,7AH ;display units digit
MOV DPTR,#TAB
MOVC A,@A+DPTR
MOV DPTR,#0002H
MOVX @DPTR,A
MOV DPTR,#0001H
MOV A,#0FB H
MOVX @DPTR,A
LJMP N7
;------delay 4MS subroutine----------
DELAY: MOV R1,#0AH
LOOP: MOV R6,#64H
NOP
LOOP1: DJNZ R6,LOOP1
DJNZ R1,LOOP
RET
;------Character table------
TAB: DB 3FH,06H,5BH,4FH,66H,6DH,7DH,07H,7FH,6FH
END