C8051F330的PWM频率周期如何方便的调整

只看该作者 · 2012-5-17 23:36

现在的做法是开中断，然后每次重装 PCA0L 和 PCA0H 才能变更频率（调试我设为16位）？
如果5个固定频率输出，我在中断中还要判断是哪个事件引起的！难道不能自动重装？？？

只看该作者 · 2012-5-17 23:37

附代码：

#include <c8051f330.h>

unsigned int CEX0_Compare_Value;    // Holds current PCA compare value

void main (void)
{
PCA0MD = 0;

// 系统时钟
OSCICN = 0x83;
CLKSEL = 0x00;

XBR0    = 0x00;
XBR1    = 0x01;

P0MDIN = 0x10;
P0MDOUT = 0x00;
P0SKIP = 0xFF;

P1MDIN = 0xFF;
P1MDOUT = 0xFF;
P1SKIP = 0xFE;

P0       = 0x00;
P1       = 0x00;

XBR1    |= 0x40;

// PCA0 INIT
PCA0CN = 0x00;
PCA0MD = 0x08;
PCA0CPM0  = 0xCB;
CEX0_Compare_Value = 65536 - (65536 * 0.5);
PCA0L    = (CEX0_Compare_Value & 0x00FF);
PCA0H    = (CEX0_Compare_Value & 0xFF00)>>8;
CEX0_Compare_Value = CEX0_Compare_Value - (CEX0_Compare_Value * 0.08);

PCA0CPL0 = (CEX0_Compare_Value & 0x00FF);
PCA0CPH0 = (CEX0_Compare_Value & 0xFF00)>>8;

EIE1 |= 0x10;

CR = 1;

EA = 1;
while(1)
{
      ;
}
}

void PCA0_ISR (void) interrupt 11
{
CCF0 = 0;                         // Clear module 0 interrupt flag.

CEX0_Compare_Value = 65536 - (65536 * 0.5);
PCA0L    = (CEX0_Compare_Value & 0x00FF);
PCA0H    = (CEX0_Compare_Value & 0xFF00)>>8;

P1 ^= 0x80;
}

只看该作者 · 2012-5-17 23:42

同问啊

只看该作者 · 2012-5-17 23:50

以T0溢出作为PCA时基即可得到连续可变的pwm频率

只看该作者 · 2012-5-17 23:54

正解！！！！！