Im using the atmel 8051 chip and using keil versus 8.18 to create my program. I have been using assmebly language in order to produce my code. I wrote a program to run a string of LEDs and when the last LED is light, and interrupt is activated in order to produce an audible beep that lasts .5 seconds. I chose a 1k Hz signal that lasts roughly .7 seconds. When I run the debug in keil, the program acts if it works properly, but when i program the chip with the program it doesn't play the tone. The last LED pauses when activated, so the interrupt is actually taking place but the tone isnt played. heres my code:

Beginning of program
ORG 00
LJMP INIT

;-Timer Interrupt 0 (INT0)-;
ORG 0BH
LJMP TF0ISR

;~Initialization~;
INIT: MOV P0,#00H
MOV P3,#00H
MOV IE,#10000010B
MOV TMOD,#0000001B

;~Main Program~;
START: ACALL DELAY
MOV P0,#00000001B
ACALL DELAY
MOV P0,#00000010B
ACALL DELAY
MOV P0,#00000100B
ACALL DELAY
MOV P0,#00001000B
ACALL DELAY
MOV P0,#00010000B
ACALL DELAY
MOV P0,#00100000B
ACALL DELAY
MOV P0,#01000000B
ACALL DELAY
MOV P0,#10000000B
SETB TF0
SJMP START

;~Sub-Routines~;
DELAY: MOV R0,#06H
TIMER: MOV TH1,#00H
MOV TL1,#00H
SETB TR1
JNB TF1,$
CLR TR1
CLR TF1
DJNZ R0,TIMER
RET

TF0ISR: MOV R1,#02H
MOV R0,#0FFH
TONE: SETB P3.0
ACALL DELAY1
CLR P3.0
ACALL DELAY1
DJNZ R0,TONE
DJNZ R1,TONE
RETI

DELAY1: MOV TH1,#0D7H
MOV TL1,#00H
SETB TR1
JNB TF1,$
CLR TR1
CLR TF1
RET

 

No where in your program starts the timer 0. Therefore, there will not be a timer 0 interrupt.