这个简单的例子用来演示飞思卡尔的MC9S08AC16的PWM模块的用法，用的开发板是我做的NSS08Kit-R1型开发板，由于所有S08单片机的PWM模块都是高度相似的，因此，这个例子对于其他型号的S08单片机也应该适用




/******************************
@ Nicrosystem Freescale S08 DevKit(NSS08Kit-R1)
@ author:bluehacker<nicrosystem@gmail.com>
@ date:2009-04-06
********************************/
/*****************************
@说明：
本程序用来测试 MC9S08AC16的 PWM功能，使用TPM2的channel0和channel1，
首先输出edge aligned pwm，输出大约10秒后再改为输出 center pwm
如此循环
****************/
#include <hidef.h> /* for EnableInterrupts macro */
#include "derivative.h" /* include peripheral declarations */
#include "delay.h"

#define BUS_CLK  4000000L
//以查询方式发送一个字节
void uart2_send_byte_poll(unsigned char c) {
    /*SCI2C2_TIE =0;
    SCI2C2_TCIE=0;
    SCI2C2_RIE=0;
    SCI2C2_ILIE=0;*/
   
    SCI2D=c;
    while(SCI2S1_TC==0);
}
//以查询方式发送一个字符串
void uart2_send_string_poll(unsigned char *str) {
  
  while(*str!=''){
    uart2_send_byte_poll(*str++);
  }
}

//设置系统时钟模式，为FEE,8MHZ的系统主频，BUS CLK为4MHZ
void init_system_clock()
{
     ICGC1=0xf8;
     ICGC2=0x89;
     while(ICGS1_LOCK==0);
}   

//初始化sci2
//设置sci2为8bit，一个停止位，无校验模式
//设置sci2发送，接收使能，中断全部禁止
//设置波特率为9600
void init_sci2()
{
    unsigned int BaudRate;
   
    BaudRate="BUS"_CLK/9600/16;
    SCI2BDH=(unsigned char)(BaudRate>>8);
    SCI2BDL=(unsigned char)(BaudRate&0x00ff);
   
    SCI2C1=0x04;
    SCI2C2=0x0c;
    SCI2C3=0x00;
}

//设置tpm2 channel0,channel1为edge-aligned pwm
//low-true pulse,1khz frequency
void init_tpm2_pwm()
{
    TPM2MODH=0x0f;
    TPM2MODL=0xa0;
   
    TPM2C0SC=0x24;
    TPM2C1SC=0x24;
    TPM2C0VH=0x02;
    TPM2C0VL=0xff;
    TPM2C1VH=0x05;
    TPM2C1VL=0xff;  
    TPM2SC=0x08;
}

void main(void) {

  EnableInterrupts; /* enable interrupts */
  /* include your code here */
  SOPT_COPE=0;//disable cop watchdog
  init_system_clock();
  init_sci2();
  
  uart2_send_string_poll((unsigned char*)("start..... "));
  uart2_send_string_poll((unsigned char*)("output edge-aligned pwm.... "));
  init_tpm2_pwm();
  for(;;) {
    //__RESET_WATCHDOG(); /* feeds the dog */
     delay_1s(10);
     //set center-aligned pwm output,high true pulse
     uart2_send_string_poll((unsigned char*)("output center-aligned pwm.... "));
     TPM2SC=0x00;
     delay_1s(1);
     TPM2C0SC=0x08;
     TPM2C1SC=0x08;
     TPM2SC=0x08;
     TPM2SC_CPWMS=1;
     delay_1s(10);
     //set edge-aligned pwm output,low-true pulse
     uart2_send_string_poll((unsigned char*)("output edge-aligned pwm.... "));
     TPM2SC=0x00;
     delay_1s(1);
     TPM2C0SC=0x24;
     TPM2C1SC=0x24;  
     TPM2SC=0x08;
  } /* loop forever */
  /* please make sure that you never leave main */
}