单片机 da（pcf8591）输出一个正弦波为什么顶部失真大神求解啊感激感激感激

╱/惔... · 发表于 2014-2-22 21:04:28

查表法给pcf8591送数据
uchar code sintable[]={0x80,0x83,0x86,0x89,0x8d,0x90,0x93,0x96,0x99,0x9c,
   0x9f,0xa2,0xa5,0xa8,0xab,0xae,0xb1,0xb4,0xb7,0xba,
   0xbc,0xbf,0xc2,0xc5,0xc7,0xca,0xcc,0xcf,0xd1,0xd4,
   0xd6,0xd8,0xda,0xdd,0xdf,0xe1,0xe3,0xe5,0xe7,0xe9,
   0xea,0xec,0xee,0xef,0xf1,0xf2,0xf4,0xf5,0xf6,0xf7,
            0xf8,0xf9,0xfa,0xfb,0xfc,0xfd,0xfd,0xfe,0xff,0xff,
   0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
   0xfe,0xfd,0xfd,0xfc,0xfb,0xfa,0xf9,0xf8,0xf7,0xf6,
   0xf5,0xf4,0xf2,0xf1,0xef,0xee,0xec,0xea,0xe9,0xe7,
   0xe5,0xe3,0xe1,0xde,0xdd,0xda,0xd8,0xd6,0xd4,0xd1,
   0xcf,0xcc,0xca,0xc7,0xc5,0xc2,0xbf,0xbc,0xba,0xb7,
   0xb4,0xb1,0xae,0xab,0xa8,0xa5,0xa2,0x9f,0x9c,0x99,
   0x96,0x93,0x90,0x8d,0x89,0x86,0x83,0x80,0x80,0x7c,
   0x79,0x76,0x72,0x6f,0x6c,0x69,0x66,0x63,0x60,0x5d,
   0x5a,0x57,0x55,0x51,0x4e,0x4c,0x48,0x45,0x43,0x40,
   0x3d,0x3a,0x38,0x35,0x33,0x30,0x2e,0x2b,0x29,0x27,
   0x25,0x22,0x20,0x1e,0x1c,0x1a,0x18,0x16,0x15,0x13,
   0x11,0x10,0x0e,0x0d,0x0b,0x0a,0x09,0x08,0x07,0x06,
   0x05,0x04,0x03,0x02,0x02,0x01,0x00,0x00,0x00,0x00,
   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x02 ,
   0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0a,0x0b,
   0x0d,0x0e,0x10,0x11,0x13,0x15,0x16,0x18,0x1a,0x1c,
   0x1e,0x20,0x22,0x25,0x27,0x29,0x2b,0x2e,0x30,0x33,
   0x35,0x38,0x3a,0x3d,0x40,0x43,0x45,0x48,0x4c,0x4e ,
   0x51,0x55,0x57,0x5a,0x5d,0x60,0x63,0x66 ,0x69,0x6c,
   0x6f,0x72,0x76,0x79,0x7c,0x80 };

送数据程序如下
while(1)
   {
   for(i=0;i<256;i++)
   {
     Pcf8591shuchuDA(sintable);
delay_lcd(10);
   }

示波器显示如图

全部程序见附件