下面給出一個(gè)設(shè)計(jì)實(shí)例,在實(shí)例中通過定時(shí)器中斷和DAC0832結(jié)合的方式來產(chǎn)生1~100KHZ的正弦波,幅度為0-Vcc/2。
首先按照下面的公式建立一個(gè)正弦波樣本表,樣表中將一個(gè)正弦波周期分成128個(gè)點(diǎn),每個(gè)點(diǎn)按7位量化(127對(duì)應(yīng)最高幅度Vcc/2):
f(x) = 64 + 63 * sin(2πx/180) x∈[0…127]
程序中使用16位定時(shí)器0產(chǎn)生取樣中斷,及定時(shí)器0的中斷時(shí)間即為正弦波的采樣周期。(T=1/(f*64))。本例中將正弦波分成64個(gè)采樣點(diǎn)輸出,及每隔兩個(gè)點(diǎn)要從采樣樣本中取出一個(gè)數(shù)DAC0832的輸入。
0.png (26.9 KB, 下載次數(shù): 89)
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2017-3-17 22:55 上傳
單片機(jī)源程序:
- #define SIN_GLOBAL 1
- #include "sin.h"
- //正弦波128個(gè)采樣點(diǎn)寄存數(shù)組
- code uchar Sin[128] = {
- 64,67,70,73,76,79,82,85,88,91,94,96,99,102,104,106,
- 109,111,113,115,117,118,120,121,123,124,125,126,126,
- 127,127,127,127,127,127,127,126,126,125,124,123,121,
- 120,118,117,115,113,111,109,106,104,102,99,96,94,91,
- 88,85,82,79,76,73,70,67,64,60,57,54,51,48,45,42,39,
- 36,33,31,28,25,23,21,18,16,14,12,10,9,7,6,4,3,2,1,
- 1,0,0,0,0,0,0,0,1,1,2,3,4,6,7,9,10,12,14,16,18,21,23,
- 25,28,31,33,36,39,42,45,48,51,54,57,60
- };
- /**********************************************************
- *函數(shù)名稱:Timer0_init(double timer0Delay)
- *函數(shù)功能:定時(shí)器0初始化
- *函數(shù)入口:timer0Delay,定時(shí)器定時(shí)時(shí)間,單位為毫秒
- *函數(shù)出口:無
- **********************************************************/
- void Timer0_init(double timer0Delay)
- {
- double time;
- double timeTemp;
- timer0TH0=0x00;
- timer0TL0=0x00;
- timeTemp=0x00;
- time=(double)(((double)12)/((F_CPU)/1000000));
- if(((double)255)*time>timer0Delay)
- {
- timer0TH0=0x00;
- timer0TL0=(uchar)(256ul-timer0Delay/time);
- }
- else
- {
- while(timeTemp>timer0Delay)
- {
- timeTemp+=time;
- timer0TH0++;
- }
- timer0TH0--;
- timeTemp=timeTemp-((double)timer0TH0)*time;
- timer0TL0=(uchar)(256ul-timeTemp/time);
- }
- TMOD|=0x01; //GATE=0,TR=1運(yùn)行;C/T=1,counter,0,timer;01十六進(jìn)制
- TH0=timer0TH0;
- TL0=timer0TL0;
- TR0=1; //timer0 控制位,為1時(shí)啟動(dòng)timer0
- ET0=1; //timer0 中斷使能
- }
- /**********************************************************
- *函數(shù)名稱:dac0832_init(void)
- *函數(shù)功能:D/A轉(zhuǎn)換芯片dac0832初始化
- *函數(shù)入口:無
- *函數(shù)出口:無
- **********************************************************/
- void dac0832_init(void)
- {
- sinCodeCount=0;
- DAC0832=Sin[0];
- }
- /**********************************************************
- *函數(shù)名稱:writeDAC0832(uchar dacDate)
- *函數(shù)功能:向D/A轉(zhuǎn)換芯片dac0832數(shù)據(jù)口寫數(shù)據(jù)
- *函數(shù)入口:dacDate
- *函數(shù)出口:無
- **********************************************************/
- void writeDAC0832(uchar dacDate)
- {
- DAC0832=dacDate;
- }
復(fù)制代碼
0.png (48.8 KB, 下載次數(shù): 109)
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2017-3-17 22:57 上傳
下載:
正弦波發(fā)生器.rar
(20.14 KB, 下載次數(shù): 182)
2017-3-17 22:57 上傳
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