;Program for giving signals to mosfet/IGBT  driver IC
;AMBA ENGINEERING
;JAY SATCHITANAND
;12MHz crystal     1MC= 1uS
;MOSFET IRFP460 500V ,20A
;MICROCONTROLLER AT89C2051
;P1.7 IR2111...R PHASE
;P1.6 IR2111...Y PHASE
;P1.5 IR2111...B PHASE
;P3.0 START 
;P3.1 STOP 
;P3.2 DOWN_SPEED 
;P3.3 UP_SPEED 
;P3.4 RELAY 
;1ph 230V 50HZ AC SUPPLY---FULL BRIDGE RECTIFIER 1N5408---RC FILTER---RELAY---FUSE---MOSFET CIRCUIT
;BOOTSTRAP CIRCUIT :CAPACITOR 220nf VOLTAGE RATING..?  DIODE UF1005
;GATE RESISTANCE 100 ohm
;NO PWM FOR VOLTAGE CONTROL,PUTTING RESISTANCE IN 325V DC RAIL TO ADJUST REQUIRED OUTPUT VOLTAGE
;NO OPTOCOUPLERS USED BETWEEN IR2111 AND PORT P1   
;REGULATED 12V AND 5V FROM STEPDOWN TRANSFORMER 230/18V ...NO SMPS
;THREE PHASE INDUCTION MOTOR: 220V 1.2A
ORG 0000H
	LJMP MAIN
ORG 000BH		;INTERRUPT ROUTINE FOR TIMER0
	CALL TOV
ORG 0030H
	MAIN:
	MOV P1,#00H       ;TO driver DRIVER IC IR2111
	MOV SP,#60H
	MOV R0,#1BH       ;50HZ
	MOV R1,#0F3H      ;
	MOV R3,#00H
	MOV A,#00H
	MOV R6,#00H

	MOV IP,#00000010B ;TIMER 0 HIGEST PRIORITY
	MOV TMOD,#01H	  ;TIMER 0 IN MODE 1 16-BIT TIMER
	MOV TL0,#1BH      ; 50Hz
	MOV TH0,#0F3H	  ; 50Hz
	MOV IE,#10000010B ;ENABLE TIMER 0 INTERRUPT
	MOV DPTR,#SIGNAL
	
	START:		;ENABLE TIMER AND SWITCH ON THE RELAY
		JB P3.0,STOP
		SETB P3.4      ;RELAY ON
		SETB TR0
		
	STOP:	;DISABLE TIMER AND SWITH OFF THE RELAY
		JB P3.1,DOWN_SPEED
		CLR TR0
		MOV P1,#00H
		CLR P3.4       ;RELAY OFF
		
	DOWN_SPEED:	;DECREASE THE FREQUENCY ,INCEREMNT THO
		JB P3.2,UP_SPEED
		CJNE R3,#05H,NEXT_DOWN
		AJMP START
	NEXT_DOWN:	
		JNC START
		INC R3
		AJMP SPEED0
                    
	UP_SPEED: ;INCEREASE THE FREQUENCY ,DECREMENT THO
	   JB P3.3,START		 
	   CJNE R3,#00H,SPEED
	   MOV R1,#0F3H   ;50HZ
	   MOV R0,#1BH    ;
	   AJMP START
	SPEED:
	   DEC R3
	   CJNE R3,#00H,SPEED0
	   MOV R1,#0F3H   ;50HZ
	   MOV R0,#1BH
	   AJMP START
   SPEED0:
      CJNE R3,#01H,SPEED1
      MOV R1,#0EFH	;40HZ
      MOV R0,#0B9H
      AJMP START
   SPEED1:
      CJNE R3,#02H,SPEED2
      MOV R1,#0EAH	;30HZ
      MOV R0,#4CH
      AJMP START
   SPEED2:
      CJNE R3,#03H,SPEED3
      MOV R1,#0DFH	;20HZ
      MOV R0,#72H
      AJMP START
   SPEED3:
      CJNE R3,#04H,START
      MOV R1,#0BEH   ;10Hz
      MOV R0,#0E5H    
      AJMP START  	
		        	
	TOV:
	 	CLR TR0
	 	MOV P1,#00H       ;ALL MOSFET OFF/DEAD 
	 	MOVC A,@A+DPTR    ; 2
	 	MOV R2,A          ; 1
	 	INC R6            ; 1
	 	MOV A,R6          ; 1
	 	CJNE A,#6,ED      ; 2
	 	MOV A,#00H        ; 1
	 	MOV R6,A          ; 1
	ED:                  
	 	MOV TL0,R0        ; 2
	 	MOV TH0,R1        ; 2 ....TOTAL DEAD TIME =11uS 
	 	MOV P1,R2         
	 	SETB TR0          ;WITH NEW COUNTER VALUES
	 	RETI
	
	SIGNAL:
	          ;RYB
		DB 10100000B   ;60      0
		DB 10000000B   ;120     1
		DB 11000000B   ;180     2
		DB 01000000B   ;240     3
		DB 01100000B   ;300     4
		DB 00100000B   ;360     5
		DB 00H
		END
	
		  

Can I know how can one end up in blowing mosfet so that i can avoid it.