單片機課程設(shè)計報告(利用蜂鳴器播放音樂)-在線瀏覽
2024-09-01 10:11本頁面
【正文】 ，而且可以調(diào)節(jié)各個音的快滿度。則1/4 。音持續(xù)時間的長短即時值，一般用拍數(shù)表示。）1） 控制發(fā)聲頻率要產(chǎn)生音頻脈沖，只要算出某一音頻的周期（1/頻率），然后將此周期除以2，即為半周期的時間。利用STC89C52RC的內(nèi)部定時器使其工作在計數(shù)器模式MODE1下，改變計數(shù)值TH0及TL0從而產(chǎn)生不同頻率。以標準音高A為例，A的頻率是440Hz，周期T=1/440=2272us。端口導(dǎo)通時間與斷開時的時間利用定時器實現(xiàn)。設(shè)晶振的頻率為f0，中斷觸發(fā)時間（半周期）為t，定時器工作在模式1時計數(shù)器的初值為THL，高8位為THL，低8位為TL。定時器在模式1下計時采用16位數(shù)，最大計數(shù)為2^161（65535），再次加一（65536）溢出觸發(fā)中斷。音頻對應(yīng)定時器初值的低8位TL=THL%(2^8)=(65536t*f/12)%256。若以十六分之一音符的時長為基本延時時間，則十六分音符只需調(diào)用一次延時程序，八分音符則需調(diào)用兩次延時程序，以此類推。字符的前四位表示音頻，可以表示0f共十六個音符。中音dosi分別編碼為1~7，高音dosi分別編碼為8~E，停頓編為0。以0xff作為曲譜的結(jié)束標志。本實驗中播放音樂使用簡譜如下：將其編碼成：uchar code sb[]={//定義送別簡譜0x54,0x32,0x52,0x88,0x64,0x84,0x58,0x54,0x12,0x22,0x34,0x22,0x12,0x28,0x00,0x00,0x54,0x32,0x52,0x86,0x72,0x64,0x84,0x58,0x54,0x22,0x32,0x46,0xf2,0x18,0x00,0x00,0x64,0x84,0x88,0x74,0x62,0x72,0x88,0x62,0x72,0x82,0x62,0x62,0x52,0x32,0x12,0x28,0x00,0x00,0x54,0x32,0x52,0x86,0x72,0x64,0x84,0x58,0x54,0x22,0x32,0x46,0xf2,0x18,0x00,0x00,0x54,0x32,0x52,0x88,0x64,0x84,0x58,0x54,0x12,0x22,0x34,0x22,0x12,0x28,0x00,0x00,0x54,0x32,0x52,0x86,0x72,0x64,0x84,0x58,0x54,0x22,0x32,0x46,0xf2,0x18,0x00,0x00}。//全局變量控制速度變換sbit fm=P1^4。sbit int1=P3^3。//用于存放定時器的高8位和低8位uchar code sb[]={//定義送別簡譜0x54,0x32,0x52,0x88,0x64,0x84,0x58,0x54,0x12,0x22,0x34,0x22,0x12,0x28,0x00,0x00,0x54,0x32,0x52,0x86,0x72,0x64,0x84,0x58,0x54,0x22,0x32,0x46,0xf2,0x18,0x00,0x00,0x64,0x84,0x88,0x74,0x62,0x72,0x88,0x62,0x72,0x82,0x62,0x62,
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