;Interactive Voice Response System For College Automation (IVRS)
;
;---------==========----------==========---------=========---------
	VISIT www.8051projects.info for more free projects
;---------==========----------==========---------=========---------
INCLUDE reg_52.pdf
RB0     EQU     000H    ; Select Register Bank 0
RB1     EQU     008H    ; Select Register Bank 1  ...

	STD   EQU   P1.3    ;DTMF OUTPUT
	Q3		EQU	P1.2
	Q2		EQU	P1.1
	Q1		EQU	P1.0
	Q0		EQU	P3.7
	
	RELAY	EQU	P1.6

	RING	EQU	P1.4
  		           
             		        
DSEG            ; This is internal data memory
ORG     20H     ; Bit adressable memory

	DTMF:  DS  1
	D0 BIT   DTMF.0
	D1	BIT	DTMF.1
	D2	BIT	DTMF.2
	D3	BIT	DTMF.3
COUNT:	DS		1

CSEG            ; Code begins here
;---------==========----------==========---------=========---------
;              PROCESSOR INTERRUPT AND RESET VECTORS  
;---------==========----------==========---------=========---------
 
         ORG     0000H    ; Reset
			MOV SP,#60H
			MOV    PSW,#RB0 
			CLR RELAY			;switch off relay
			MOV TMOD,#20H			; initilize timer 1 for baud rate generation for serial port
			MOV TH1,#0FDH			;select 9600bps
			MOV SCON,#50H
			SETB TR1			;start timer
			

MAIN:		SETB STD		;make STD pin as input
   		SETB RING		; make ring signal pin as input
   		

			JB RING,$			;chk Tele Ring
			AJMP PICK_PHONE
;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   			
;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   			
PICK_PHONE:
			CALL DELAYS			;Wait for 4 rings
			MOV R2,#0AH			;delay program
TP3:		MOV R0,#0FFH
TP2:		MOV R1,#0FFH
TP1:		JNB RING,SDCD1
			DJNZ R1,TP1
			DJNZ R0,TP2
			DJNZ R2,TP3
			AJMP DISCONN
SDCD1:	SETB RELAY					;take the phone
			CALL DELAY
			MOV A,#'A' 			;INFORM COMPUTER to start process
TOOP:		CALL TRANS
			SETB STD
		
			MOV R2,#90H			;wait for DTMF signal 
TA3:		MOV R0,#0FFH
TA2:		MOV R1,#0FFH
TA1:		JB STD,SDCD2
			DJNZ R1,TA1
			DJNZ R0,TA2
			DJNZ R2,TA3
			AJMP DISCONN			;if no signal for 5min disconnect the phone
			
SDCD2:	CALL READ
			MOV A,DTMF
			CJNE A,#0CH,TOOPS		
			AJMP DISCONN			

TOOPS:	CJNE A,#0AH,RFT1
			MOV A,#30H
			AJMP TOOP
RFT1:		CJNE A,#0BH,RFT2
			MOV A,#40H	
			AJMP TOOP	
RFT2:		ADD A,#30H	
			AJMP TOOP						
			
TRANS:
			MOV SBUF,A			;send dialled data to PC
			JNB TI,$
			CLR TI	
			RET		
;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   			
DELAYS:
			MOV R2,#0AH			;delay program
EP3:		MOV R0,#0FFH
EP2:		MOV R1,#0FFH
EP1:		NOP
			DJNZ R1,EP1
			DJNZ R0,EP2
			DJNZ R2,EP3
			RET  
;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%					
DISCONN:	MOV A,#'B'			;disconnect telephone
			CALL TRANS		; sent char B to pc that telephone is disconnected
			CLR RELAY
			CALL DELAY
			CALL DELAY
			AJMP MAIN	  	;jump to main progrm	
;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
;				READ DTMF TONES
;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%		
READ:	MOV DTMF,#00H			;read DTMF code from the IC
		SETB Q0
		SETB Q1
		SETB Q2
		SETB Q3
		JNB Q0,VB1
		SETB D0
VB1:	JNB Q1,VB2
		SETB D1		
VB2:	JNB Q2,VB3
		SETB D2
VB3:	JNB Q3,VB4
		SETB D3
VB4:	JB STD,$
		RET		
;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%	
DELAY:						;delay program
		MOV R0,#0FFH
REP2:	MOV R1,#0FFH
REP1:	NOP
		DJNZ R1,REP1
		DJNZ R0,REP2
		RET       
 ;***********************************************************************
	END