Keyboard Synthesizer Using AT89S52

This is basically a keyboard synthesizer which is made using the 8051 microcontrollers. The keyboard of our P.C is utilized to play the notes .
The notes are played by the small speaker connected to the microcontroller.
ULN2803 is use to drive the speaker.

The U.A.R.T. of the 8051is utilized to send information from the pc to the microcontroller.
The notes of the music are played using the frequencies of different notes of music. Each octave in the synthesizer operates on a different frequency range and the corresponding values of the timer can be calculated using the frequencies of each note that can be easily found on the internet.


As per my calculations the different values to be loaded on timer for different octaves and corresponding notes are as follows. The timer should loaded with a value so that the time to overflow should be half the period of frequency´s note and turn on and of the speaker at each overflow ocurrency.

speaker on off on
|--------------| |--------
____| |__________________|
| half-period |

|<>|

The different decimal values to be loaded into the timer for the note generation corresponding to the different octaves are given as follows.

63441,63559,63670,63775,63874,63967,64055,64138,64217, 64291,64360,64426**4th octave

64489,64547,64603,64655,64705,64751,64795,64837,64876, 64913,64948,64981**5th octave

65012,65042,65069,65096,65120,65144,65166,65187,65206, 65225,65242,65259**6th octave

65274,65289,65303,65316,65328,65340,65351,65361,65371, 65380,65389,65397**7th octave

65405,65412,65419,65426,65432,65438,65443,65449,65454, 65458,65463,65467**8th octave

Here is the source code for the above project.