C8T6输出PWM占空比100%是否达不到？

只看该作者 · 2020-6-19 14:30

如题，当单片机供电由J-LINK仿真器提供，电源为3.2468V，占空比100%时，测量电压为3.2378V，差不多相差10MV。当单片机供电由TPS70933提供，电源为3.2973，输出测量为3.2681V，相差30MV。
其中均采用定时器1的互补2通道。
Tim1_Init(7199,0);

void  Tim1_Init(u16 arr,u16 psc)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
GPIO_InitTypeDef GPIO_InitStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);

// RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB|RCC_APB2Periph_AFIO, ENABLE);

GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_14 ;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);

  TIM_TimeBaseStructure.TIM_Period = arr;                   // ´Ó×°±È½Ï×î´ó 18k  = 72000/ 6000= 12k
  TIM_TimeBaseStructure.TIM_Prescaler = psc;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;    //  Ä£Ê½  Ôö
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;                //  ·ÖÆµ
// TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
  TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);

  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
TIM_OCInitStructure.TIM_Pulse = arr  ;
TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High;

TIM_OC2Init(TIM1, &TIM_OCInitStructure);
TIM_OC2PreloadConfig(TIM1, TIM_OCPreload_Enable);

//TIM_ARRPreloadConfig(TIM1, ENABLE);

TIM_Cmd(TIM1, ENABLE);//¼ÆÊý¿ªÊ¼
TIM_CtrlPWMOutputs(TIM1, ENABLE);

// TIM_ClearFlag(TIM1, TIM_FLAG_Update);
// TIM_ClearITPendingBit(TIM1, TIM_IT_Update);  //ÇåÖÐ¶Ï±êÖ¾Î»
//  TIM_ITConfig(TIM1,TIM_IT_Update ,ENABLE); //´ò¿ªÖÐ¶Ï


//ÅäÖÃTIM1µÄ¸üÐÂÖÐ¶ÏÊ¹ÄÜ
NVIC_InitStructure.NVIC_IRQChannel = TIM1_UP_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;//Ö¸¶¨ÇÀÕ¼ÓÅÏÈ¼¶1
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;//Ö¸¶¨ÏìÓ¦ÓÅÏÈ¼¶0
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}