akaj
thank you for replying to my question
i want to use the 8051 to generate a pulse stream of differant frequencies and therefore produce an audible tone.i will hope fully produce 5 differant tones by varying the frequencies of the signal.

a DIP switich will determine which tone is played.
a buzzer will produce the tone
COMPONENTS:TTL Hex driver
:buzzer
:transistor swiched

a code specifying the required tone ,is inputted to the 8051,from the DIP swotich.a pulse stream will be produced and heard on the buzzer.
i would also like to be able two add tones together.
i am trying to write the softeware in machine code but i have no expirence so any code would be a great help.
cheers
mark