新唐Nano130 PWM抖动的问题

只看该作者 · 2013-9-2 10:28

最近在学习新唐nano130，发现PWM 有抖动的情况。附件所示：程序如下：请高人们解析：
int32_t main (void)
{
      S_DRVPWM_TIME_DATA_T sPt;
      ////STR_PDMA_T sPDMA;

      uint8_t u8Timer;

      int32_t i32TestLoop = 1;
      uint8_t u8ItemOK;
      /* Enable PWM clock */
      PWM_Init(0);

      /* Set PWM pins */
      GCR->PA_H_MFP = (GCR->PA_H_MFP & ~(PA12_MFP_MASK | PA13_MFP_MASK | PA15_MFP_MASK)) |
   PA12_MFP_PWM0_CH0 | PA13_MFP_PWM0_CH1 | PA15_MFP_PWM0_CH3;
   GCR->PB_H_MFP = (GCR->PB_H_MFP & ~PB11_MFP_MASK) | PB11_MFP_PWM1_CH0;
   GCR->PE_L_MFP = (GCR->PE_L_MFP & ~PE0_MFP_MASK) | PE0_MFP_PWM1_CH2;


   while (i32TestLoop)
         {
               u8ItemOK = 1;
               g_u16Frequency = 100;
            if (i32TestLoop && u8ItemOK)
               {
               g_u32Pulse = 0;
               g_u8PWMCount = 1;
               /* PWM Timer property */
               /*
               * clock = 12MHz / 2 = 6Mhz.
               * CN = clock / freq - 1
               */
               sPt.u8Mode = PWM_CTL_CHMOD_AUTO_RELOAD;
               sPt.u8PreScale = 1;  // actually 1 + 1
               sPt.u8Div = PWM_CLKSEL_CLKSEL_DIV1;
               sPt.u32Cn = 6000000 / g_u16Frequency - 1;
               sPt.u16Cm = sPt.u32Cn / 2; // 50% duty ratio
               sPt.u8Inv = 0; // Disable inverter
               u8Timer = 0;

               /* Set PWM Timer0 Configuration */
               PWM_SetClk(u8Timer, &sPt);
               /* Enable Output for PWM Timer0 */
               PWM_ConfigOutput(u8Timer, 1);
               /* Enable Interrupt Sources of PWM Timer0 and install call back function */
               //// PWM_EnableInt(u8Timer);
               /* Enable the PWM Timer 0 */
               PWM_Enable(u8Timer);
               while (g_u8PWMCount);
               while(1);
                        }
                     }

            }