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There are seven pitch classes which are represented by first seven letters of Latin alphabets (A, B, C, D, E, F and G). A musical note is represented by Pitch class and octave level, So according to pitch classes there are basic 7 notes and 8th note is represented with as same pitch class as first but double the frequency. The octave is used to differentiate between two notes and is a representation of frequency ratio of two.

Musical notes start from C0, c0#, D0, D0#,.... the lowest note frequency i.e. for C0 is 16.35Hz (based on center frequency A4, 440Hz). Another major component of musical note is duration. There are total 10 durations which are Quarter, Whole, Half, Eighth, Sixteenth, Thirty Two, Sixtyfour, six, twelve and twenty four. These durations vary depending on tempo (beats per minute) of the music/tone.

In music library we focused on notes from C5 to B6 as they coveres almost all variations for simple tone generation and octave level is produce good sound level on hardware (lower frequency means lower sound, higher the frequency higher the sound).


Generating a particular frequency is nothing but a square wave with desired time period. We can use one of the 8051's timer to generate a particular frequency. Lets say if you want to generate C5 note which has a frequency of 523.25Hz, the time period for C5 will be 1911.132µS. The output square wave with 50% duty cycle will have high and low time of 955.566µS (= 1911.132/2).

Lets say your controller running at 12Mhz oscillator will have one Machine cycle of 1µs. To generate 955.566µs we need 956 (~=955.566/1) machine cycles. We can load timer with a value of 64580 (65536-956) and toggle any I/O pin at that interval will give us the reqired frequency. Now this I/o pin can be connected to a speaker to produce sound for that note.

In the library provided we are using Timer2 in auto reload mode for square wave generation. You can use any timer i.e. timer0 or timer1 in 16bit mode for frequency generation. For your convenience I have provided an excel sheet that will generate timer values for a given crystal oscillator frequency.

You can also download the sample tone recorded and tested using this library:

The sample program and hex file produces following tones:
1. Adam's Family
2. Looney Toons
3. Flintstones
4. Pink Panther
5. Beethoven Play
6. SaReGaMa (Basic Indian sound 7 tones in forward and reverse order).

If you have any doubt regarding this library please make use of forum

Tags play music 8051tone generation 8051pwm sound 8051musical notes 8051play musical notes 8051

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03 Apr 2019: 16:36 PM
Can i see the circuit diagram please?
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Mon Jun 17 2019, 05:33 PM
Sun Jun 16 2019, 07:48 PM
hanoch Taub
i need to interface sim800 to 8051, the problem is that on the module sim800 there are 9 pins connector and I don't know how to connect him to 8051, which pins to tx and rx on 8051 module sim there is
Tue May 28 2019, 07:14 PM
Ron Otsig
KBI does not work on P89LPC920 but it works on P89LPC925
Mon May 27 2019, 09:03 AM
Hello friends....
Tue May 21 2019, 03:02 PM
Hi. Who is online?
Tue May 14 2019, 12:38 AM
Jayson Contreras
Sun Apr 28 2019, 09:06 AM
Please provide me the code for gsm based sms controlled notice board
Sun Apr 14 2019, 10:52 PM
@hassan malik post your problem in the "General help Guidance and Discussion" forum
Sun Apr 14 2019, 05:06 PM
please send me code to interface atmega32 with 24c1024 serial eeprom
Sun Apr 14 2019, 01:33 PM
hassan malik
hello sir i installed proteus 7.8 professional on window 7 ultimate and window 10 but there would be same errors onn both windows. the error is bad license key.please any one help me



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JenniferJJ Avatar
Posted By JenniferJJ
Thu Jun 13 2019, 05:17 AM
Hi,Hello Members,I am the newbie member, I like ve...
ExperimenterUK Avatar
Posted By ExperimenterUK
Thu May 30 2019, 08:32 PM
It occurs to me that although the P89LPC921 and P8...
ExperimenterUK Avatar
Posted By ExperimenterUK
Wed May 29 2019, 09:05 PM
I would suggest a fresh approach.The Keil compile...
ronotsig Avatar
Posted By ronotsig
Wed May 29 2019, 03:13 PM
Since the code works for the P89LPC925, it is appa...
ExperimenterUK Avatar
Posted By ExperimenterUK
Mon May 27 2019, 06:23 PM
I can't see any reason that those registers would ...
ronotsig Avatar
Posted By ronotsig
Mon May 27 2019, 03:06 AM
I am trying to using P89LPC921 or P89LPC922 in a p...
Ansh12 Avatar
Posted By Ansh12
Sun Apr 28 2019, 02:15 PM
I made a minor change, it works in Proteus.Try the...
ExperimenterUK Avatar
Posted By ExperimenterUK
Thu Apr 25 2019, 08:20 PM
I made a minor change, it works in Proteus.Try the...
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Posted By gigyani
Thu Apr 25 2019, 01:17 AM
when i add cufirst.hex its not working.after 2-3 s...
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Posted By ExperimenterUK
Wed Apr 24 2019, 12:29 AM