Code-8051 microcontroller (assembly language).txt

ORG 0000H 
LJMP START
MESSAGE1: DB “SOIL MOISTURE”,0FH 
MESSAGE2: DB “DETECTION”,0FH 
MESSAGE3: DB “PLACE THE PROBE”,0FH 
MESSAGE4: DB “MOISTURE VALUE”,0FH 
MOTOR: DB “MOTOR ON”,0FH
 ORG 0050H 
START: CLR P3.0 ;output for motor circuit
 CLR P3.3 ;output for less
 CLR P3.4 
CLR P3.5 
CLR P3.6 
MOV P1,#0FFH ; configuring as input for ADC 
LCALL INIT ; LCD init routine 
MOV DPTR,#MESSAGE1 ; message pointer
 LCALL DISPCH2 ; display on LCD 
MOV A,#0C0H ; command for lcd 2 nd line
LCALL CMD ; command routine for LCD 
MOV DPTR,#MESSAGE2 
LCALL DISPCH2 
LCALL DELAY 
MOV A,#01H ;command for clear lcd 
LCALL CMD 
MOV A,#80H ;command for first line 
LCALL CMD MOV DPTR ,#MESSAGE3 
LCALL DISPCH2 
LCALL DELAY1
 MESG_VAL:MOV A,#01H 
LCALL CMD 
MOV A,#80H
LCALL CMD 
MOV DPTR ,#MESSAGE4 
LCALL DISPCH2 
REPEAT: SETB P2.0 ;CS for adc 
SETB P2.1 ; RD for adc 
SETB P2.2 ;WR for adc 
SETB P2.3 ;INTR for adc 
LCALL ADC_READ ; return the ADC value in A reg 
LCALL PERCENT ;to calculate percentage 
MOV R4,A 
LCALL BCD ; hex to bcd conversion FF > 255 
LCALL UNPACK ; BCD to ASCII ;returns value in 62h, 61h and 60h 
location ; 
255 > 02 05 05 > 32 35 35 
LCALL OUTPUT ;display the result
MOV A,R4 ;check for RELAY on if 5%%<percent<20%
CJNE A,#5H,CHK2 ;5% 
CHK2:JNC OK ;check carry flag
 SJMP LED_CHK
 OK:CJNE A,#14H,CHK3 ;20% 
CHK3:JNC LED_CHK 
LCALL TILL 
SJMP MESG_VAL 
LED_CHK:CJNE A,#3CH,LCHK ;LED ON FOR PERCENT>60%
LCHK:JNC L_ON ;CHECK carry flag 
SJMP BACK 
L_ON:LCALL LED_R
 BACK: SJMP REPEAT 
ADC_READ: 
CLR P2.0 ;CS=0 
LCALL DELAY 
CLR P2.2 ;WR 
NOP 
SETB P2.2 ; WR 
SETB P2.0 ;CS=1 
HERE1: JB P2.3, HERE1 ; INTR PIN POLLING 
CLR P2.0 ;CS=0 
CLR P2.1 ; RD
MOV A,P1 
SETB P2.0 
SETB P2.1 
SETB P2.3 
LCALL DELAY 
RET
PERCENT:MOV B,#33H ;51D 
DIV AB 
MOV 75H,B 
MOV B,#14H ;20D 
MUL AB 
MOV 50H,A 
MOV A,#100 
SUBB A,50H ;subtract the value from 100 
MOV R0,75H 
CJNE R0,#25,CK ;varying the percentage based on remainder 
CK:JNC check_3_4 
SJMP Check_1_4 
check_3_4:CJNE R0,#38,CK2 
CK2:JNC AD 
SUBB A,#9
 sjmp T 
AD:SUBB A,#15 
SJMP T 
Check_1_4: CJNE R0,#12,CK3 
CK3:JNC SD 
SJMP T 
SD:SUBB A,#5 
T:RET 
BCD:MOV A,R4 ;hex to bcd conversion 
MOV R3,A 
CJNE A,#00H, SKIP2 
MOV R6,A 
MOV R7,A 
RET 
SKIP2: CLR A 
MOV R7,A 
UP1: ADD A,#01H 
DA A 
JNC SKP 
INC R7 
SKP: DJNZ R3,UP1 
MOV R6,A 
RET 
UNPACK:MOV A,R7 ;unpack bcd values 
ADD A,#30H 
MOV 62H,A 
MOV A,R6 
ANL A,#0FH 
ADD A,#30H 
MOV 60H,A 
MOV A,R6 
SWAP A 
ANL A,#0FH 
ADD A,#30H 
MOV 61H,A 
RET 
OUTPUT:MOV A,#0C0H ; command for lcd 2 nd line 
LCALL CMD ; command routine for LCD 
MOV A,62H 
LCALL DISP ; display a byte on LCD 
MOV A,61H 
LCALL DISP 
LCALL DELAY 
MOV A,60H 
LCALL DISP
LCALL DELAY 
MOV A,#25H 
LCALL DISP 
LCALL DELAY1 
RET 
TILL: MOV A,#01H ;function for motor 
LCALL CMD
 MOV A,#80H ;command for first line 
LCALL CMD MOV DPTR,#MOTOR ; message pointer 
LCALL DISPCH2 
SETB P3.0 ;MOTOR on 
LCALL DELAY1 
LCALL DELAY1 
CLR P3.0 
LCALL DELAY1
 LCALL DELAY1 
LCALL DELAY1
 LCALL ADC_READ ; return the ADC value in A reg 
LCALL PERCENT 
MOV R4,A 
LCALL BCD 
LCALL UNPACK 
MOV A,#01H
 LCALL CMD
 MOV A,#80H 
LCALL CMD 
MOV DPTR ,#MESSAGE4 
LCALL DISPCH2 
LCALL OUTPUT 
MOV A,R4 
CJNE A,#28H,CHK ;40% 
CHK:JC TILL 
RET 
LED_R: SETB P3.3 ;LED 
SETB P3.4 
SETB P3.5 
SETB P3.6 
LCALL DELAY1 
CLR P3.3 
CLR P3.4 
CLR P3.5 
CLR P3.6 
RET 
INIT:MOV A,#3CH ;refer manual for the bit meaning 
LCALL CMD 
MOV A,#3CH 
LCALL CMD 
MOV A,#3CH 
LCALL CMD 
MOV A,#0EH
 LCALL CMD 
MOV A,#06H
LCALL CMD 
MOV A,#01 
LCALL CMD 
RET 
CMD:LCALL READY 
MOV P0,A 
CLR p2.5 ; low on RS 
CLR p2.6 
SETB p2.7 ; high to low on En line 
LCALL DELAY 
CLR p2.7 
RET 
DISP:LCALL READY 
MOV P0, A 
SETB p2.5 ; high RS 
CLR p2.6 ;; low RW 
SETB p2.7 ; high to low En 
CLR p2.7 
RET 
READY:CLR 0A7H ;read busy flag 
MOV P0,#0FFH 
CLR 0A5H 
SETB 0A6H 
WAIT:CLR 0A7H 
LCALL DELAY 
SETB 0A7H 
JB p0.7,WAIT 
RET 
DELAY: MOV R6,#0ffh ;delay routine for firing 
HERE3: MOV R5,#0ffH 
REPEAT1: DJNZ R5,REPEAT1 
DJNZ R6,HERE3 
RET 
DELAY1: MOV R5,#0AH 
BACK: MOV R1,#0FFH 
BACK1: MOV R0,#0FFH 
BACK2: DJNZ R0,BACK2 
DJNZ R1,BACK1 
DJNZ R5,BACK 
RET 
DISPCH2:NOP 
UP11: CLR A 
MOVC A,@A+DPTR ;use lookup table to get ascii character 
CJNE A,#0FH,SKIP5 
RET 
SKIP5: INC DPTR 
LCALL DISP
 SJMP UP11
 END