1. code unsigned char FREQH[] = {
    2.     0xF2, 0xF3, 0xF5, 0xF5, 0xF6, 0xF7, 0xF8,       //低音1234567
    3.     0xF9, 0xF9, 0xFA, 0xFA, 0xFB, 0xFB, 0xFC, 0xFC, //1,2,3,4,5,6,7,i
    4.     0xFC, 0xFD, 0xFD, 0xFD, 0xFD, 0xFE,             //高音 234567
    5.     0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFF};      //超高音 1234567
    6. // 频率-半周期数据表 低八位
    7. code unsigned char FREQL[] = {
    8.     0x42, 0xC1, 0x17, 0xB6, 0xD0, 0xD1, 0xB6,       //低音1234567
    9.     0x21, 0xE1, 0x8C, 0xD8, 0x68, 0xE9, 0x5B, 0x8F, //1,2,3,4,5,6,7,i
    10.     0xEE, 0x44, 0x6B, 0xB4, 0xF4, 0x2D,             //高音 234567
    11.     0x47, 0x77, 0xA2, 0xB6, 0xDA, 0xFA, 0x16};      //超高音 1234567
    13. void t0int() interrupt 1 //T0中断程序，控制发音的音调
    14. {
    15.     TR0 = 0;        //先关闭T0
    16.     beep = !beep;   //输出方波, 发音
    17.     TH0 = FREQH[k]; //下次的中断时间, 这个时间, 控制音调高低
    18.     TL0 = FREQL[k];
    19.     TR0 = 1; //启动T0
    20. }