Objective is when ever Telephone Set goes off hook , controller detects off hook and sents a Dial Tone to the telephone set for 20 Seconds and after 20 seconds program END.  Using 12 MHz Crystal.  Firstly the Program do nothing untill a logical high signal comes at P1.0.  When a Logical high Signal somes at P1.0,  Timer 0 interrupt comes in act  1000 Hz square wave is produced at P2.0.  Now how I can make controller to sent this upto 20 seconds and,  After that sents a Busy TONE type of Sound by generating the same square wave but with 0.1 second ON and 0.1 Second OFF. ORG 00H LJMP MAIN ORG 000BH CPL P2.0 RETI MAIN: JNB P1.0,$ JMP DIAL TONE DIAL TONE: MOV TMOD,#20H MOV TH0,,#-50 SETB TR0 MOV IE,#82H Upto 20 seconds DIAL TONE and after that BUSY TONE keeps on going. END
Nver mind ,i have solvd my problem thank u 4 ur help You just saved 10 seconds typing in stupid SMS and made everyone trying to read your post spend 30 seconds trying to decipher it. Erik
Nver mind ,i have solvd my problem thank u 4 ur help
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