disPIC30F片子PWM的问题
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disPIC30f片子PWM的问题
我想弄一个SPWM的波,但是现在占空比随周期在变,不知道PWM输出后还要加什么东西滤波或者怎么样,直接加个电容连接一个电阻看到的波很不理想,是正弦波但是周期相当大,这个是面积等效法作的50HZ的实验,实际是要做20到300赫兹可调的.所用调试环境MPLAB ICD2 v8.10 编译器是C30,外部有4M的晶振,再有就是PTPER时间怎么算,,更改其中的值,滤波后正弦波周期基本没有变化.希望各位不吝赐教,程序在附件中,用示波器看256个数是1微秒,所以在PTPER中25600是100个微秒,程序中建了两表一个是100个点的,一个是64点的,100点的中间去掉了两个数
#include
#include
#include
#define PI 3.141592
_FOSC(CSW_FSCM_OFF & HS) //HS振荡器,禁止时钟切换
_FWDT(FWDTEN_OFF); //禁止看门狗定时器
//_FBORPOR(PBOR_OFF & MCLR_EN); //禁止掉电复位,使能MCLR复位
_FGS(CODE_PROT_OFF);
int N,f=20;
double Pul;
int
BUFcos[98]={5,5,24,35,44,54,64,73,86,93,101,111,120,130,138,147,156,164, 172,181,188,197,204,211,219,226,232,239,245,251,257,263,268,272,278,282,2 87,
290,294,297,300,303,306,308,309,311,312,313,314,314,313,312,311,309,308,3 06,
303,300,297,294,290,287,282,278,272,268,263,257,251,245,239,232,226,219,2 11,
204,197,188,181,172,164,156,147,138,130,120,111,101,93,86,73,64,54,44,35, 24,
5,5},
BUFcos1[64]={12,36,60,84,108,131,154,176,199,221,242,262,283,302,320,340 ,355,372,387,401,415,427,438,449,458,466,473,479,484,487,489,491
,491,489,487,484,479,473,466,458,449,438,427,415,401,387,372,355
,340,320,302,283,262,242,221,199,176,154,131,108,84,60,36,12};
void Delay(int x)
{ //延时程序while(x--);
}
void SCAN()
{
int i; //键盘扫描程序 // k=0;
//double M=1.0,w=2*PI*f;
PORTB=0x03;
if(PORTB!=0x03)
{
for(i=0;i<10;i++)
{
Delay(25600);
}
if(PORTBbits.RB0==0) //S2定义为增
{
f=f+20;
if(f>300)
{
f=20;
}
}
else if(PORTBbits.RB1==0) //S3定义为减{
f=f-20;
if(f<20)
{
f=300;
}
}
}
}
void Pulse_Width(void) //PWM波程序
{
int k=0;
double M=1.0,w=2*PI*f;
for(k=10;k<90;k++)
{
PTPER=25700;
/*~~~~~~ Load PDC1 register with initial Duty Cycle value ~~~~~~~~~~*/
//Pul=(M/w)*(cos((k-1)*PI/N)-cos(k*PI/N));
//PDC1=Pul*256*1000000;
PDC1=(0.3183*BUFcos[k]*256); //其中0.3183是M/w
Delay(200); //延迟100微秒
}
}
void Pulse_Config()
{
TRISE=0x00;
FCLCON1=0X0003;
/*~~~~~~~~~~~~~~~~~~~~~~~ PWM1 Configuration ~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/* PWM1 I/O Control Register register /
IOCON1bits.PENH = 1; /* PWM1H is controlled by PWM module */
IOCON1bits.PENL = 1; /* PWM1L is co*ntrolled by PWM module */
IOCON1bits.PMOD = 0; /* Select Independent Output PWM mode */
IOCON1bits.POLH = 0;
/* Load PDTR1 and ALTDTR2 register with preset dead time value */
DTR1 = 64; /* Deadtime setting */
ALTDTR1 = 64; /* Deadtime setting */
/* PHASE1 register */
PHASE1 = 0; /* No phase shift */
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~*/