The Research And Design Implementation Of Late-model Keyboard Electronic Musical Instrument

Computer music can be seen everywhere in our life, the creation of many kinds of music has been separated from musical performance at present.It was replaced by computer music,which was created by computer. Keyboard electronic musical instrument has transformed successfully from traditional keyboard to electronic keyboard. It will become a preferred and mainstream instrument because of its timbre, melody and performance. From the research of this technology at home and abroad, the study and realization of keyboard electronic musical instrument will become a design goal,which is the most favorite for the designers.The General keyboard electronic musical instrument often adopts piano keyboard, there is 12 keys in every 8 range compass.Among of them, it concludes 7 white key and 5 black key. The pitch interval is minor second of equal temperament between every adjacent keyboard. This kind of keyboard make electronic keyboard play the music with arbitrary tonality, although it has a plenty of obvious shortcomings-playing is so difficult and specialized requirement is so strict. IIn my design I use the new keyboard electronic instrument, which is as follows:it cancelled all black keys, that is, there are only 7 keyboards in every 8 range compass. This method reduces the number of keyboards sharply. The place of keynote "1" is fixed on this keyboard, the player don't require changing fingering any more, and on every keyboard we can mark numeral notation's pitch name. The choice of tonality consists of a group of interlock switch.In this design, we can choose 8 tonalities to use, such as C,D,#E,E,F,G,A,B. The whole system circuit is comprised of the master chip AT89C51,the UART interface circuit, MIDI source of sound and the keyboard scanning matrix module. After the design and fabrication of hardware circuit, the simulation and programming of software, it achieves the design's aim—laying the music on the new keyboard electronic instrument.Based on the speculation knowledge of computer music and MIDI technology, in addition, there is a unique keyboard design and a simulator called WeiFu devised function program, this design has achieved inherent function of electronic organ.And I explored preliminary in the electronic organ field.From hardware and software, the result is reflected in 3 aspects.First, this design regarded AT89C51 as master control chip,which can be control the periphery circuit. And I used 2 74LS148 chips in order to expand 14 external interrupt sources.Finally, it achieves electronic organ's design individuality.Second, after processing and editing, we used the new MIDI keyboard—cancelling 5 black keyboards.I took a group of interlock switch as tonality selection key, which is unprecedented in the design history of electronic organ.Third, in the stage of software design, we can see main program is simplify and bantam.There are so many interrupt programs, although it is more troublesome, it make the whole system fit the people's operation habit.