/*任意周期和任意占空比DUTY%的PWM*/
#define CYCLE 6000L //定义PWM周期(最大值为32767)
sbit PWM2=P3^7;
sbit PWM3=P2^1;
sbit PWM4=P2^2;
void pwminit()
{ P_SW2 |= 0x80;
PWMCFG = 0x00; //配置PWM的输出初始电平为低电平
PWMCKS = 0x0f; //选择PWM的时钟为Fosc/(0+1)
PWMC = CYCLE; //设置PWM周期,定义PWM周期(最大值为32767)
PWM2CR = 0x00; //选择PWM2输出到P3.7,不使能PWM2中断
PWM3CR = 0x00;
PWM4CR = 0x00;
PWM2T1 = 0x0001;
PWM2T2 = 0;
PWM3T1 = 0x0001;
PWM3T2 = 0;
PWM4T1 = 0x0001;
PWM4T2 = 0;
PWMCR |= 0x80; //使能PWM模块
P_SW2 &=~0x80;
}
void pwm2( unsigned int DUTY) //PWM2
{
if(DUTY==0)
{
PWMCR &=~0x01;
PWM2=0;
}
else if (DUTY==100)
{
PWMCR &=~0x01;
PWM2=1;
}
else
{
P_SW2 |= 0x80; //使能访问PWM在扩展RAM区的特殊功能寄存器XSFR
PWM2T1 = 0x0001; //设置PWM2第1次反转的PWM计数
PWM2T2 = CYCLE * DUTY / 100; //设置PWM2第2次反转的PWM计数
P_SW2 &=~0x80; //占空比为(PWM2T2-PWM2T1)/PWMC
PWMCR |= 0x01; //使能PWM信号输出
}
}
void pwm3(unsigned int DUTY) //PWM3
{
if(DUTY==0)
{
PWMCR &=~0x02;
PWM3=0;
}
else if(DUTY==100)
{
PWMCR &=~0x02;
PWM3=1;
}
else
{
P_SW2 |= 0x80;
PWM3T1 = 0x0001;
PWM3T2 = CYCLE * DUTY / 100;
P_SW2 &=~0x80;
PWMCR |= 0x02;
}
}
void pwm4(unsigned int DUTY) //PWM4
{
if(DUTY==0)
{
PWMCR &=~0x04;
PWM4=0;
}
else if (DUTY==100)
{
PWMCR &=~0x04;
PWM4=1;
}
else
{
P_SW2 |= 0x80;
PWM4T1 = 0x0001;
PWM4T2 = CYCLE * DUTY / 100;
P_SW2 &=~0x80;
PWMCR |= 0x04;
}
}
