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[STM32F0]

stm32f0 怎样提高固件库例子里面的pwminput捕获的频率、占空比精度

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jmworkspace|  楼主 | 2014-5-20 19:52 | 只看该作者 回帖奖励 |倒序浏览 |阅读模式
用stm32f0discovery固件库里面的input_pwm例子输出的波形与实际我的信号发生器产生的波形不大一样,这是什么问题?该怎么才能使两者一样?
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jmworkspace|  楼主 | 2014-5-20 19:57 | 只看该作者
/**
  ******************************************************************************
  ******************************************************************************
  * <h2><center>&copy; COPYRIGHT 2012 STMicroelectronics</center></h2>
  *
  * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
  * You may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *        http://www.st.com/software_license_agreement_liberty_v2
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "stm32f0xx.h"

/** @addtogroup STM32F0_Discovery_Peripheral_Examples
  * @{
  */

/** @addtogroup TIM_PWM_Input
  * @{
  */

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
TIM_ICInitTypeDef  TIM_ICInitStructure;
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;
GPIO_InitTypeDef GPIO_InitStructure;

extern __IO uint32_t Frequency;
extern __IO uint16_t DutyCycle;

/* Private function prototypes -----------------------------------------------*/
void TIM_Config(void);
void Output_TIM_Config(void);
/* Private functions ---------------------------------------------------------*/

/**
  * @brief  Main program.
  * @param  None
  * @retval None
  */
int main(void)
{
  /*!< At this stage the microcontroller clock setting is already configured,
       this is done through SystemInit() function which is called from startup
       file (startup_stm32f0xx.s) before to branch to application main.
       To reconfigure the default setting of SystemInit() function, refer to
       system_stm32f0xx.c file
     */

  /* TIM Configuration */
  TIM_Config();
  Output_TIM_Config();
  /* ---------------------------------------------------------------------------
    TIM2 configuration: PWM Input mode

    In this example TIM2 input clock (TIM2CLK) is set to APB1 clock (PCLK1)   
      TIM2CLK = PCLK1
      => TIM2CLK = HCLK = SystemCoreClock

    External Signal Frequency = TIM3 counter clock / TIM3_CCR2 in Hz.

    External Signal DutyCycle = (TIM3_CCR1*100)/(TIM3_CCR2) in %.

  --------------------------------------------------------------------------- */
  
  TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;
  TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
  TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
  TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
  TIM_ICInitStructure.TIM_ICFilter = 0x0;

  TIM_PWMIConfig(TIM3, &TIM_ICInitStructure);

  /* Select the TIM3 Input Trigger: TI2FP2 */
  TIM_SelectInputTrigger(TIM3, TIM_TS_TI2FP2);

  /* Select the slave Mode: Reset Mode */
  TIM_SelectSlaveMode(TIM3, TIM_SlaveMode_Reset);
  TIM_SelectMasterSlaveMode(TIM3,TIM_MasterSlaveMode_Enable);

  /* TIM enable counter */
  TIM_Cmd(TIM3, ENABLE);

  /* Enable the CC2 Interrupt Request */
  TIM_ITConfig(TIM3, TIM_IT_CC2, ENABLE);
       

  /* TIM1 Main Output Enable */
  TIM_CtrlPWMOutputs(TIM3, ENABLE);
       
  /* Infinite loop */
  while (1)
  {
        }
}

/**
  * @brief  Configure the TIM IRQ Handler.
  * @param  None
  * @retval None
  */
void TIM_Config(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;
  
  /* TIM3 clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
  
  /* GPIOA clock enable */
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
  
  /* TIM3 chennel2 configuration : PA.01 */
  GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_1;
  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_UP ;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
  
  /* Connect TIM pin to AF3 */
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource1, GPIO_AF_2);
  
  /* Enable the TIM3 global Interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}

void Output_TIM_Config(void)
{

  /* GPIOA Clocks enable */
  RCC_AHBPeriphClockCmd( RCC_AHBPeriph_GPIOA, ENABLE);
  
  /* GPIOA Configuration: Channel 1, 2, 3 and 4 as alternate function push-pull */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11 ;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP ;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
  
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource11, GPIO_AF_2);
       
        /* TIM1 clock enable */
        RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
       
        /* Time Base configuration */
  TIM_TimeBaseStructure.TIM_Prescaler = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseStructure.TIM_Period = Frequency;
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
       
        /* Channel 1, 2, 3 and 4 Configuration in PWM mode */
  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
  TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High;
  TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
  TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;
       
        TIM_OCInitStructure.TIM_Pulse = DutyCycle;
  TIM_OC1Init(TIM1, &TIM_OCInitStructure);
}
       
        #ifdef  USE_FULL_ASSERT

/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t* file, uint32_t line)
{
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */

  /* Infinite loop */
  while (1)
  {
  }
}
#endif

/**
  * @}
  */

/**
  * @}
  */

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

如上是我的主函数



void TIM3_IRQHandler(void)
{
  RCC_ClocksTypeDef RCC_Clocks;
  RCC_GetClocksFreq(&RCC_Clocks);

  /* Clear TIM2 Capture compare interrupt pending bit */
  TIM_ClearITPendingBit(TIM3, TIM_IT_CC3);

  /* Get the Input Capture value */
  IC3Value = TIM_GetCapture2(TIM3);

  if (IC3Value != 0)
  {
    /* Duty cycle computation */
    DutyCycle = (TIM_GetCapture1(TIM3) * 100) / IC3Value;
    /* Frequency computation
       TIM3 counter clock = (RCC_Clocks.HCLK_Frequency)/2 */

    Frequency = 72000000 / IC3Value;
               
  }
  else
  {
    DutyCycle = 0;
    Frequency = 0;
  }

如上这是我的中断函数

实际测出来的波形高电平感觉是原来信号发生器的低电平的比例,占空比一调到13%就没有波形了
这是怎么回事 还有频率调节只能在0~100hz 调大就没波形了。  

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板凳
jmworkspace|  楼主 | 2014-5-20 19:58 | 只看该作者
我就想得到的波形跟实际波形是一模一样的 其他参数该怎么设置或者哪里设置错误了呢?求大神指点~

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地板
icecut| | 2014-5-20 20:08 | 只看该作者
Frequency = 72000000 / IC3Value;
M默认频率是72吗?

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5
mmuuss586| | 2014-5-20 22:13 | 只看该作者
现在差多少呢???百分比

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6
553010746| | 2014-5-20 22:57 | 只看该作者
同问 占空比 比较小时 pwm就没了

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7
jmworkspace|  楼主 | 2014-5-21 08:40 | 只看该作者
mmuuss586 发表于 2014-5-20 22:13
现在差多少呢???百分比

当占空比调到13%以下,就没有波形了,当频率调大于10Hz就没有波形了

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