PWM控制蜂鸣器实验

1.     程序实现

5.1 Timer0 初始化程序

void INT_Timer_Initialize(void)

{

 /*++++++++++++++++++++++++++++++++++++++++++++++++++++*/

 /*                                                           */

 /*     Fout(s)=[(prescaler+1)*(TCNTB+1)]/[pclk*divider]=40ms      */

 /*                                                                     */

 /*+++++++++++++++++++++++++++++++++++++++++++++++++++       +*/

         rTCFG0=0x64; //prescaler0 100

         rTCFG1=0x01; //divide value 1/4

         rTCNTB0=5000;         //TCNTB=5000

         rTCON=0x0a;  //auto load, invert off, manual update, stop timer

         /*INTIALIZE THE INTERRUPT*/

         rINTMOD=0x0;        //all irq

         rINTMSK=0xffffffff;            //disable all interrupt source

         rINTSUBMSK=0xffff;                  //disable all sub interrupt source

}

 

5.2 开启timer0中断

/* open the interrupt timer0 and eint0 */

void ENABLE_INTERRUPT(void)

{

         rINTMSK=~(BIT_TIMER0);

         rTCON=0x09;

}

 

5.3 测试主函数

int Main()

{

            

    SetClockDivider(1, 1);

         SetSysFclk(DFT_FCLK_VAL);

         Port_Init();

                  

         Uart_Select(0);

         Uart_Init(0, UART_BAUD);

   

    //timer0初始化

    INT_Timer_Initialize();         

        

         //建立中断向量表

         pISR_TIMER0=(unsigned)timer0Handler;

        

         //开中断

         ENABLE_INTERRUPT();

        

         Uart_Printf("the main is running\n");

 

    while(1);

 }

 

5.4 timer0中断服务子程序

void __irq timer0Handler(void)

{

    printf("timer0 is running.\n");

    ClearPending(BIT_TIMER0);

}