单片机STC8A8K64D4通过串口传输来设置PWM占空比的程序

下面是STC8A8K64D4通过串口传输设置PWM占空比的示例代码：

#include "stc8.h"

#define FOSC 24000000UL
#define BAUD 115200UL
#define TIMER_PRESCALER 12
#define PWM_PRESCALER 2

sbit LED = P1^0;

void UART_Init(void)
{
    SCON = 0x50;
    TMOD &= 0x0F;
    TMOD |= 0x20;
    TL1 = TH1 = -(FOSC/12/BAUD);
    TR1 = 1;
}

void Timer1_Init(void)
{
    TMOD &= 0xF0;
    TMOD |= 0x01;
    TH1 = (65536 - FOSC/12/TIMER_PRESCALER/1000) >> 8;
    TL1 = (65536 - FOSC/12/TIMER_PRESCALER/1000) & 0xFF;
    ET1 = 1;
    TR1 = 1;
}

void PWM_Init(void)
{
    P_SW2 &= ~0x80;
    P1M1 |= 0x01;
    P1M0 &= ~0x01;
    PWMCKS = PWM_PRESCALER;
    PWMCFG |= 0x80;
    PWMCR = 0x00;
    PWMIF = 0;
    PWMIE = 1;
}

void PWM_SetDutyCycle(unsigned int duty)
{
    PWM0H = (unsigned char)(duty >> 8);
    PWM0L = (unsigned char)duty;
}

void main(void)
{
    UART_Init();
    Timer1_Init();
    PWM_Init();
    EA = 1;
    while(1);
}

void Timer1_Isr(void) interrupt 3
{
    static unsigned char buf[4];
    static unsigned char cnt = 0;
    if(RI)
    {
        RI = 0;
        buf[cnt++] = SBUF;
        if(cnt == 4)
        {
            unsigned int duty = (buf[0] << 8) | buf[1];
            unsigned int period = (buf[2] << 8) | buf[3];
            PWM_SetDutyCycle(duty);
            TH1 = (65536 - period) >> 8;
            TL1 = (65536 - period) & 0xFF;
            cnt = 0;
        }
    }
}

void PWM_Isr(void) interrupt 12
{
    PWMIF = 0;
    LED = !LED;
}

该程序通过串口接收4个字节的数据，前两个字节表示PWM占空比，后两个字节表示PWM周期，然后设置PWM占空比和PWM周期，并在PWM中断中切换LED状态以示波形输出。需要注意的是，该程序使用了定时器1来控制PWM周期，因此需要根据实际情况调整定时器1的分频系数。