简易低频信号源设计(编辑修改稿)

简易低频信号源设计(编辑修改稿)内容摘要：

L初值为 65535，高八位为 65535除以 256，余数放在低八位；计数器选择 16位的定时模式；允许 T1 中断，开定时器。 键扫描子程序 键扫描子程序的任务是检查 3个按键是否有键按下，若有键按下，则执行相应的功能。 在这里， 3 个按键分别用于频率增加、频率减少和正弦波和三角波的选择功能。 键扫描子程序流程图和程序如下。 图 键扫描子程序流程图 /******************************************* 键 扫 描 子 函 数**********************************/ keyscan() 简易低频信号源设计 7 { keyword=keyamp。 0x07。 if(keyword!=0x07) { while((keyamp。 0x07)!=0x07)。 switch(keyword) { case6:{if(THHL=65235)THHL=65535。 else{THHL=THHL+255。 }break。 } case5:{if(THHL=500)THHL=0。 else{THHL=THHL255。 }break。 } case3:{sin_thr=~sin_thr。 break。 } default:{break。 } } } } // 波形数据产生子程序 波形数据产生子程序是定时器 T1的中断程序。 当定时器计数溢出时，发生一次中断。 当发生中断时，单片机将按次序将波形数据表中的波形数据一一送入到 DAC0832，DAC0832再根据输入的数据大小输出对 应的的电压。 波形数据产生子程序流程图和程序如下。 //********************************************T1 中断函数*********************************/ void time_intt1(void) interrupt 3 { EA=0。 TR1=0。 TH1=THHL/256。 TL1=THHL%256。 TR1=1。 if(sin_thr){dataout=sin_tab[n]。 } else{dataout=thr_tab[n]。 } if(n=255){n=0。 }else{n++。 } ww=~ww。 EA=1。 } //***************************************** 结束*****************************************、 沈阳工程学院课程设计（论文） 8 图 波形数据产生子程序流程 波形查找表程序 三角波查找表 /***************************三角波数据表 ****************************/ uchar code thr_tab[256]= { 0x80,0x81,0x82,0x83,0x84,0x85,0x86,0x87, 0x88,0x89,0x8A,0x8B,0x8C,0x8D,0x8E,0x8F, 0x90,0x91,0x92,0x93,0x94,0x95,0x96,0x97, 0x98,0x99,0x9A,0x9B,0x9C,0x9D,0x9E,0x9F, 0xA0,0xA1,0xA2,0xA3,0xA4,0xA5,0xA6,0xA7, 0xA8,0xA9,0xAA,0xAB,0xAC,0xAD,0xAE,0xAF, 0xB0,0xB1,0xB2,0xB3,0xB4,0xB5,0xB6,0xB7, 0xB8,0xB9,0xBA,0xBB,0xBC,0xBD,0xBE,0xBF, 0xBF,0xBE,0xBD,0xBC,0xBB,0xBA,0xB9,0xB8, 0xB7,0xB6,0xB5,0xB4,0xB3,0xB2,0xB1,0xB0, 0xAF,0xAE,0xAD,0xAC,0xAB,0xAA,0xA9,0xA8, 0xA7,0xA6,0xA5,0xA4,0xA3,0xA2,0xA1,0xA0, 0x9F,0x9E,0x9D,0x9C,0x9B,0x9A,0x99,0x98, 0x97,0x96,0x95,0x94,0x93,0x92,0x91,0x90, 0x8F,0x8E,0x8D,0x8C,0x8B,0x8A,0x89,0x88, 简易低频信号源设计 9 0x87,0x86,0x85,0x84,0x83,0x82,0x81,0x80, 0x7F,0x7E,0x7D,0x7C,0x7B,0x7A,0x79,0x78, 0x77,0x76,0x75,0x74,0x73,0x72,0x71,0x70, 0x6F,0x6E,0x6D,0x6C,0x6B,0x6A,0x69,0x68, 0x66,0x66,0x65,0x64,0x63,0x62,0x61,0x60, 0x5F,0x5E,0x5D,0x5C,0x5B,0x5A,0x59,0x58, 0x55,0x55,0x55,0x54,0x53,0x52,0x51,0x50, 0x4F,0x4E,0x4D,0x4C,0x4B,0x4A,0x49,0x48, 0x44,0x44,0x45,0x44,0x43,0x42,0x41,0x40, 0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47, 0x48,0x49,0x4A,0x4B,0x4C,0x4D,0x4E,0x4F, 0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57, 0x58,0x59,0x5A,0x5B,0x5C,0x5D,0x5E,0x5F, 0x60,0x61,0x62,0x63,0x66,0x65,0x66,0x67, 0x68,0x69,0x6A,0x6B,0x6C,0x6D,0x6E,0x6F, 0x70,0x71,0x72,0x73,0x77,0x75,0x76,0x77, 0x78,0x79,0x7A,0x7B,0x7C,0x7D,0x7E,0x7F}。 // 正弦波查找表 /*****************************正弦波数据表 ****************************/ uchar code sin_tab[256]= {0x80,0x83,0x85,0x88,0x8A,0x8D,0x8F,0x92, 0x94,0x97,0x99,0x9B,0x9E,0xA0,0xA3,0xA5, 0xA7,0xAA,0xAC,0xAE,0xB1,0xB3,0xB5,0XB7, 0xB9,0XBB,0xBD,0XBF,0xC1,0xC3,0xC5,0xC7, 0xC9,0xCB,0xCC,0xCE,0xD0,0xD1,0xD3,0xD4, 0xD6,0xD7,0xD8,0xDA,0xDB,0xDC,0xDD,0xDE, 0xDF,0xE0,0xE1,0xE2,0xE3,0xE3,0xE4,0xE4, 0xE5,0xE5,0xE6,0xE6,0xE7,0xE7,0xE7,0xE7, 0xE7,0xE7,0xE7,0xE7,0xE6,0xE6,0xE5,0xE5, 0xE4,0xE4,0xE3,0xE3,0xE2,0xE1,0xE0,0xDF, 0xDE,0xDD,0xDC,0xDB,0xDA,0xD8,0xD7,0xD6, 0xD4,0xD3,0xD1,0xD0,0xCE,0xCC,0xCB,0xC9, 0xC7,0xC5,0xC3,0xC1,0xBF,0xBD,0xBB,0xB9, 0xB7,0xB5,0xB3,0xB1,0xAE,0xAC,0xAA,0xA7, 0xA5,0xA3,0xA0,0x9E,0x9B,0x99,0x97,0x94, 0x92,0x8F,0x8D,0x8A,0x88,0x85,0x83,0x80, 0x7D,0x7B,0x78,0x76,0x73,0x71,0x6E,0x6C, 0x69,0x67,0x65,0x62,0x60,0x5D,0x5B,0x59, 0x56,0x54,0x52,0x4F,0x4D,0x4B,0x49,0x47, 0x45,0x43,0x41,0x3F,0x3D,0x3B,0x39,0x37, 沈阳工程学院课程设计（论文） 10 0x35,0x34,0x32,0x30,0x2F,0x2D,0x2C,0x2A, 0x29,0x28,0x26,0x25,0x24,0x23,0x22,0x21, 0x20,0x1F,0x1E,0x1D,0x1D,0x1C,0x1C,0x1B, 0。