使用过程中，发现pwm频率大于设定频率

只看该作者 · 2015-2-27 16:41

本帖最后由 M.gtd 于 2015-3-1 16:48 编辑

晶振频率 8MHz
mcu频率 72MHz
pwm初始化----------------------------------------
  TIM_DeInit(TIM1);
  TIM_TimeBaseStructInit(&TIM1_TimeBaseStructure);
  /* Time Base configuration */
  TIM1_TimeBaseStructure.TIM_Prescaler = 0x0;                            //internal clock with no dividing
  TIM1_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_CenterAligned1;//
  TIM1_TimeBaseStructure.TIM_Period = 4500;                      //频率设计为72M/(4500*2)=8k
  TIM1_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV2;             //for dead time clock

  // Initial condition is REP=1 to set the UPDATE only on the underflow
  TIM1_TimeBaseStructure.TIM_RepetitionCounter = REP_RATE;       //REP_RATE=1;
  TIM_TimeBaseInit(TIM1, &TIM1_TimeBaseStructure);

  TIM_OCStructInit(&TIM1_OCInitStructure);
------------------------------------------------------------------------------
使用过程中发现pwm频率大于8K，在8.8K左右，百思不得其解，会不会是晶振不准？