;----------------------------------------------------------------------------------------;
;THIS PROGRAM CONTROL A FAN AND A HEATER DEPENDING ON THE REFERENCE INPUT AND THE PRESENT; 
;ROOM TEMPERATURE AS READ BY THE ADC0804.TEMPERATURE IS DISPLAYED CONTINUOUSLY ON THE TWO;
;SEVEN SEGMENTS WHICH ARE SCANNED BY THIS CODE.NEW REFERENCE TEMPERATURE CAN BE ENTERED  ;
;BY UP & DOWN PUSH BUTTONS.                                                              ;
;----------------------------------------------------------------------------------------;
;This code is written by Mubashar Yasin(Islamabad,Pakistan).It is freely distributable   ;
;however please distribute it with my name and if you add this code to your website or   ;
;some other publication then mention about me along with this code.I have tested this    ;
;code to work properly even then there is no guarantee or warranty and i cannot be held  ; 
;responsible for any damage or loss due to this code.If you have any querries about this ; 
;code please contact me at:                                                              ;
;                                                                                        ;
;  kool_projects@yahoo.com                                                               ;
;  mubasharpk09@hotmail.com                                                              ;
;                                                                                        ;
;or visit my website:                                                                    ;
;                                                                                        ;
;  http://www.geocities.com/kool_projects                                                ;
;----------------------------------------------------------------------------------------;
	
	  COUNT EQU -10000
	DIGITAL EQU P1
	  WRITE EQU P2.0
	   INTR EQU P2.1
	SELECT0 EQU P2.2
	SELECT1 EQU P2.3
	     UP EQU P2.4
	   DOWN EQU P2.5
	  ENTER EQU P2.6
	    FAN EQU P3.0
	 HEATER EQU P3.1
        
	ORG 0000H
	LJMP MAIN

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
ADJUST:
; 149 cycles for 2 bytes,  77 cycles for 1 byte
	;MOV	r1,#0AFH	; 175d
	;MOV	r2,#91H		; 91AFH = 37295d

; Result:  R7=3, R6=7, ..., R3=5

; All 8 registers are used, and also A and B

	MOV	R5,#0
	MOV	R6,#0
	MOV	R7,#0

	MOV	A,R1
	MOV	B,#10
	DIV	AB
	
	MOV	R3,B		; Lower byte, in R1, is transformed into 2 decade digits,
	MOV	R4,A		; it's OK that the higher one can be greater than 9

	MOV	A,R2		; Higher byte is in R2
	JZ	SPRING		; Spring over if 0
	MOV	B,#10
	DIV	AB

	MOV	R5,B		; Same as for lower byte
	MOV	R6,A

; Value in R5 is 256 times higher than value standing in R3, R4. Mply R5 with 6,
; add to R3, mply R5 with 5, add to R4, mply R5 with 2 and replace itself in R5

	MOV	R0,#05		; Point to R5
	ACALL	TRANSF		; Transform R5 to 3 lower positions

	INC	R0		; Repeat from R6, now all registers are 1 higher
	ACALL	TRANSF		; Transform R6 to 3 higher positions

SPRING:	MOV	R0,#03		; Point to lowest digit

; Adjust to decimal, everything higher than 9 should be, as 1 tenth, added to higher.
; Starting from the lowest digit, divide with 10, keep the rest, and add the 1/10th to
; first higher place (eg. 145, leave 5 and add 14 to the next higher)

	ACALL	DECADJ

	RET

TRANSF:	MOV	A,@R0
	MOV	B,#6
	MUL	AB
	DEC	R0
	DEC	R0
	ADD	A,@R0
	MOV	@R0,A

	INC	R0
	INC	R0
	MOV	A,@R0
	MOV	B,#5
	MUL	AB
	DEC	R0
	ADD	A,@R0
	MOV	@R0,A

	INC	R0
	MOV	A,@R0
	RL	A		; Mply with 2
	MOV	@R0,A

	RET

DECADJ:	MOV	A,@R0
DECLOP:	MOV	B,#10
	DIV	AB
	MOV	@R0,B
	INC	R0
	ADD	A,@R0
	MOV	@R0,A
	
	CJNE	R0,#7,DECLOP
	RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;
LOOK_UP:
;;;;;;;;;;;;
	INC A
        MOVC A,@A+PC
	RET
	TABLE:DB 0x40,0x7C,0x12,0x18,0x2C,0x09,0x01,0x5C,0x00,0x08 ;COMMON ANODE DISPLAY
;;;;;;;;;;;
DELAY:
;;;;;;;;;;;
	MOV TMOD,#01H
	MOV TH0,#HIGH COUNT
	MOV TL0,#LOW COUNT
	SETB TR0
	RET
;;;;;;;;;;;;
UP_READ:
;;;;;;;;;;;;
	JNB UP,$    ; WAIT FOR KEY RELEASE
	USING 2
	INC R1
	LCALL ADJUST
	LCALL REF_DISPLAY
	USING 0
	RET
;;;;;;;;;;;;
DOWN_READ:
;;;;;;;;;;;;
	JNB DOWN,$
	USING 2
	DEC R1
	LCALL ADJUST
	LCALL REF_DISPLAY
	USING 0
	RET
;;;;;;;;;;;;
ENTER_READ:
;;;;;;;;;;;;
	JNB ENTER,$
	USING 2
	LCALL ADJUST
	LCALL REF_DISPLAY
	USING 0
	RET
;;;;;;;;;;;;
REF_DISPLAY:
;;;;;;;;;;;;
	MOV R0,#0x64
ZZZ:	LCALL DELAY
REPEAT2:MOV P0,#0xFF
	CLR SELECT1
	SETB SELECT0
	MOV P0,R3  ;display lower digit
	SETB P0.7  ;DOT TO SHOW IT IS REF
	MOV P0,#0xFF
	CLR SELECT0
	SETB SELECT1
	MOV P0,R4  ;display high digit
	SETB P0.7  ;DOT ACTIVE
	JNB TF0,REPEAT2
	CLR SELECT1
	CLR TF0
	CLR TR0
	DJNZ R0,ZZZ
	RET
;;;;;;;;;;;;
DISPLAY:
;;;;;;;;;;;;
	MOV R0,#0xFF
ZZ:	LCALL DELAY
REPEAT:	MOV P0,#0xFF
	CLR SELECT1
	SETB SELECT0
	MOV P0,R3  ;display lower digit
	MOV P0,#0xFF
	CLR SELECT0
	SETB SELECT1
	MOV P0,R4  ;display high digit
	JNB TF0,REPEAT
	CLR SELECT1
	CLR TF0
	CLR TR0
	JNB UP,UP_PRESSED  ;READING THE INPUT KEYS(ACTIVE LOW)
	JNB DOWN,DOWN_PRESSED
	JNB ENTER,ENTER_PRESSED
	SJMP KK
	UP_PRESSED:LCALL UP_READ
	SJMP KK
	DOWN_PRESSED:LCALL DOWN_READ
	SJMP KK
	ENTER_PRESSED:LCALL ENTER_READ
KK:	DJNZ R0,ZZ
	RET
;;;;;;;;;;;;;        
MAIN:
;;;;;;;;;;;;;
	USING 2
	MOV R1,#25 ;INITIALIZE REF
	USING 0
	MOV R2,#0 ;initialize R2

AGAIN:	CLR WRITE
      	SETB WRITE     ;toggle write(start conversion)
      	JB INTR,$      ;wait for ADC interrupt
      	MOV R1,DIGITAL ;read ADC
      	LCALL ADJUST   ;convert binary in R1 to bcd in R3 & R4
      	;;;;;;;
      	USING 2
      	MOV A,R1
      	USING 0
      	CLR C
      	SUBB A,R1
      	JC FAN_ON
      	CLR FAN
      	SETB HEATER
      	SJMP JJ
      	FAN_ON:
      	SETB FAN
      	CLR HEATER
JJ:
	;;;;;;;
	MOV A,R3
      	LCALL LOOK_UP
      	MOV R3,A
      	MOV A,R4
      	LCALL LOOK_UP
      	MOV R4,A
      	LCALL DISPLAY
	SJMP AGAIN
	END