基于C51单片机电子琴的设计与实现

断是1到7按键还是8按键，若是1到7按键被按下则启动定时器T1，按照音阶所对应的周期初始值数组表中的初值，输出方波信号；当判断是第八个按键被按下时，直接调用挥着翅膀的女孩歌曲的音调和节拍数组，启用中断循环输出。

各个音阶的频率以及对应半周期如下图所示：

通过Time0的溢出中断实现单频产生。Time0的溢出中断发生后输出引脚的电压反向，然后定时器重新装入初值。所以编程时要确定Time0的工作模式和计数初值。这里采用工作模式1，定时器的初值设定通过软件重复实现。而且定时器的初值则依据各音频频率设置。例如：中音Do音频是523Hz，其周期T=l／523=1 912μs，其半周期为1912／2=956μs。本设计的计时时钟周期是lμs，因此设置Time0的计数器每计956次则中断一次，从而实现Do的音频，然后通过中断触发实现引脚电压的循环取反得到相应音频输出。

4.硬件电路与程序设计

4.1电路图：

我们按键部分用AT89C51的P0口，而该芯片的P0需接上拉电阻，一共需要八个，因此我们用9引脚的排阻代替，排阻多出来的一个引脚接VCC。

4.2程序框图

经过以上分析论证，最终我们得到如下框图。 按键模 硬件复 系统时 AT89C51 放大电声音模块 5.软件程序

#include #include

#define uchar unsigned char #define uint unsigned int sbit buz=P3^1; uchar keycode; uchar i,j; uint

toneh[8]={ 0xfc43,0xfcab,0xfd09,0xfd33,0xfd81,0xfdc7,0xfe05,0xfe21};

uchar keymode[8]={ 0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f}; unsigned char code Music_hzcb[]={ 0x17,0x02, 0x15,0x03,0x16,0x03, 0x18,0x03,0x19,0x02, 0x18,0x03,0x17,0x03, 0x18,0x02,0x10,0x03, 0x16,0x03,0x17,0x02, 0x1A,0x03,0x1B,0x03, 0x18,0x03,0x19,0x02, 0x17,0x03,0x18,0x03,

0x17,0x03, 0x17,0x03, 0x16,0x03, 0x15,0x02, 0x15,0x03, 0x17,0x03, 0x1F,0x03, 0x16,0x03, 0x1F,0x03,

0x18,0x03, 0x17,0x03, 0x17,0x03, 0x18,0x03, 0x16,0x02, 0x18,0x03, 0x1F,0x03, 0x17,0x03, 0x1F,0x02,

0x19,0x02, 0x17,0x03, 0x18,0x02, 0x17,0x03, 0x15,0x03, 0x19,0x02, 0x17,0x03, 0x18,0x03, 0x16,0x03,

0x17,0x03,0x18,0x03, 0x20,0x02,0x1F,0x03,

0x17,0x03, 0x1B,0x03,

0x18,0x03, 0x1F,0x66,

0x20,0x03, 0x20,0x03,

0x21,0x03,0x20,0x03, 0x1F,0x03, 0x1B,0x03, 0x1F,0x66, 0x1F,0x03, 0x1B,0x03, 0x19,0x03, 0x19,0x03, 0x15,0x03, 0x1A,0x66,0x1A,0x03, 0x19,0x03, 0x15,0x03, 0x15,0x03, 0x17,0x03,0x16,0x66, 0x17,0x04, 0x18,0x04, 0x18,0x03, 0x19,0x03,0x1F,0x03, 0x1B,0x03, 0x1F,0x66, 0x20,0x03, 0x21,0x03,0x20,0x03, 0x1F,0x03, 0x1B,0x03, 0x1F,0x66, 0x1F,0x03,0x1B,0x03, 0x1A,0x66,0x1A,0x03, 0x1B,0x03,0x1F,0x00, 0x1B,0x03,0x1B,0x03, 0x17,0x03,0x15,0x17,

0x19,0x03, 0x19,0x03, 0x1A,0x03, 0x1A,0x03, 0x15,0x03,

0x19,0x03, 0x19,0x03, 0x1A,0x03, 0x19,0x03, 0x16,0x03,

0x15,0x03, 0x1F,0x03, 0x1A,0x03, 0x19,0x02, 0x17,0x03,

0x18,0x03,0x17,0x04, 0x18,0x0E, 0x18,0x03, 0x17,0x04, 0x18,0x0E, 0x18,0x66, 0x17,0x03, 0x18,0x03, 0x17,0x03, 0x18,0x03,0x20,0x03, 0x20,0x02, 0x1F,0x03, 0x1B,0x03, 0x1F,0x66,0x20,0x03, 0x21,0x03, 0x20,0x03, 0x1F,0x03, 0x1B,0x03,0x1F,0x66, 0x1F,0x04, 0x1B,0x0E, 0x1B,0x03, 0x19,0x03,0x19,0x03, 0x15,0x03, 0x1A,0x66, 0x1A,0x03, 0x19,0x03,0x15,0x03, 0x17,0x04,0x18,0x04, 0x1B,0x03,0x1F,0x66, 0x1F,0x03,0x1B,0x03, 0x19,0x03,0x19,0x03,

0x15,0x03, 0x18,0x03, 0x20,0x03, 0x1F,0x66, 0x15,0x03,

0x17,0x03, 0x19,0x03, 0x21,0x03, 0x1F,0x03, 0x1A,0x66,

0x16,0x66, 0x1F,0x03, 0x20,0x03, 0x1B,0x03, 0x1A,0x03,