STM32一个Timer输出4路不同频率、可调占空比的PWM

源码下载地址：http://download.csdn.net/detail/dazhou158/5253187

main.c

 /*********************************************
     标题：操作USART的练习
     软件平台：MDK-ARM Standard Version4.70
     硬件平台：stm32f4-discovery
     主频：168M
     Periph_Driver_version: V1.0.0

     描述：用一个定时器(TIM3)，实现四路不同频率、占空比可调的PWM
           代码参考自STM32F4-Discovery_FW_V1.1.0\Project\Peripheral_Examples\TIM_TimeBase

     author：大舟
     data：2013-04-13
 **********************************************/

 #include "stm32f4_discovery.h"



 TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
 TIM_OCInitTypeDef  TIM_OCInitStructure;
 __IO uint16_t CCR1_Val = 5000;//54618
 __IO uint16_t CCR2_Val = 27309;
 __IO uint16_t CCR3_Val = 13654;
 __IO uint16_t CCR4_Val = 6826;
 uint16_t PrescalerValue = 0;

 void TIM_Config(void);


 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_stm32f4xx.s) before to branch to application main.
        To reconfigure the default setting of SystemInit() function, refer to
        system_stm32f4xx.c file
      */

   /* TIM Configuration */
   TIM_Config();

   /** -----------------------------------------------------------------------
     TIM3 Configuration: Output Compare Timing Mode:

     In this example TIM3 input clock (TIM3CLK) is set to 2 * APB1 clock (PCLK1),
     since APB1 prescaler is different from 1.
       TIM3CLK = 2 * PCLK1
       PCLK1 = HCLK / 4
       => TIM3CLK = HCLK / 2 = SystemCoreClock /2

     To get TIM3 counter clock at 500 KHz, the prescaler is computed as follows:
        Prescaler = (TIM3CLK / TIM3 counter clock) - 1
        Prescaler = ((SystemCoreClock /2) /50 MHz) - 1

     CC1 update rate = TIM3 counter clock / CCR1_Val = 9.154 Hz  @note 上面已经将CCR1_Val改为了5000，具体频率，见中断的注释
     ==> Toggling frequency = 4.57 Hz

     C2 update rate = TIM3 counter clock / CCR2_Val = 18.31 Hz
     ==> Toggling frequency = 9.15 Hz

     CC3 update rate = TIM3 counter clock / CCR3_Val = 36.62 Hz
     ==> Toggling frequency = 18.31 Hz

     CC4 update rate = TIM3 counter clock / CCR4_Val = 73.25 Hz
     ==> Toggling frequency = 36.62 Hz

     Note:
      SystemCoreClock variable holds HCLK frequency and is defined in system_stm32f4xx.c file.
      Each time the core clock (HCLK) changes, user had to call SystemCoreClockUpdate()
      function to update SystemCoreClock variable value. Otherwise, any configuration
      based on this variable will be incorrect.
   ----------------------------------------------------------------------- */

   /* Compute the prescaler value */
   PrescalerValue = (uint16_t) ((SystemCoreClock / 2) / 500000) - 1;//=168

   /* Time base configuration */
   TIM_TimeBaseStructure.TIM_Period = 65535;//65535
   TIM_TimeBaseStructure.TIM_Prescaler = 0;
   TIM_TimeBaseStructure.TIM_ClockDivision = 0;
   TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

   TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

   /* Prescaler configuration */
   TIM_PrescalerConfig(TIM3, PrescalerValue, TIM_PSCReloadMode_Immediate);//对84M进行168分频，即为500KHz

   /* Output Compare Timing Mode configuration: Channel1 */
   TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Timing;
   TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
   TIM_OCInitStructure.TIM_Pulse = CCR1_Val;
   TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
   TIM_OC1Init(TIM3, &TIM_OCInitStructure);
   TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Disable);

   /* Output Compare Timing Mode configuration: Channel2 */
   TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
   TIM_OCInitStructure.TIM_Pulse = CCR2_Val;
   TIM_OC2Init(TIM3, &TIM_OCInitStructure);
   TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Disable);

   /* Output Compare Timing Mode configuration: Channel3 */
   TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
   TIM_OCInitStructure.TIM_Pulse = CCR3_Val;
   TIM_OC3Init(TIM3, &TIM_OCInitStructure);
   TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Disable);

   /* Output Compare Timing Mode configuration: Channel4 */
   TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
   TIM_OCInitStructure.TIM_Pulse = CCR4_Val;
   TIM_OC4Init(TIM3, &TIM_OCInitStructure);
   TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Disable);

   /* TIM Interrupts enable */
   TIM_ITConfig(TIM3, TIM_IT_CC1 | TIM_IT_CC2 | TIM_IT_CC3 | TIM_IT_CC4, ENABLE);

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

   while (1);
 }



 /**
   * @brief  Configure the TIM IRQ Handler.
   * @param  None
   * @retval None
   */
 void TIM_Config(void)
 {
   NVIC_InitTypeDef NVIC_InitStructure;

   /* TIM3 clock enable */
   RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

   /* Enable the TIM3 gloabal Interrupt */
   NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
   NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
   NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
   NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
   NVIC_Init(&NVIC_InitStructure);

   /* Initialize Leds mounted on STM32F4-Discovery board */
   STM_EVAL_LEDInit(LED4);
   STM_EVAL_LEDInit(LED3);
   STM_EVAL_LEDInit(LED5);
   STM_EVAL_LEDInit(LED6);

   /* Turn on LED4, LED3, LED5 and LED6 */
   STM_EVAL_LEDOn(LED4);
   STM_EVAL_LEDOn(LED3);
   STM_EVAL_LEDOn(LED5);
   STM_EVAL_LEDOn(LED6);
 }






 #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) */

   while (1)
   {}
 }
 #endif

 /******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE****/

stm32f4xx_it.c

 #include "stm32f4xx_it.h"
 #include "stm32f4_discovery.h"

 uint16_t capture = 0;
 extern __IO uint16_t CCR1_Val;
 extern __IO uint16_t CCR2_Val;
 extern __IO uint16_t CCR3_Val;
 extern __IO uint16_t CCR4_Val;


 /**
 实际上当CCR1_Val每次都变化时，就可以用来改变占空比
 */
 void TIM3_IRQHandler(void)
 {
     /*7500为一个循环，周期为7500/500000=0.015，频率为66.67Hz*/
     if (TIM_GetITStatus(TIM3, TIM_IT_CC1) != RESET)
     {
         TIM_ClearITPendingBit(TIM3, TIM_IT_CC1);

         if(CCR1_Val==5000)
         {
             STM_EVAL_LEDOn(LED4);   //PD12=0。ARR增加5000后，到达这条语句。
             CCR1_Val=2500;          //所以低电平的百分比为5000/7500=2/3。即占空比为1/3
         }
         else
         {
             STM_EVAL_LEDOff(LED4);  //PD12=1
             CCR1_Val=5000;
         }
         capture = TIM_GetCapture1(TIM3);
         TIM_SetCompare1(TIM3, capture + CCR1_Val);//在原来的CCR1（即capture）基础上加5000，则再过5000，又会触发中断
         //另外，有个问题，进入中断时，当ARR计数器快加到65535，而又不足5000时，不是会有数据多余，而产生波形的移动吗？
         //回答：不用担心。例如进入中断是，ARR=65000，65000+5000=70000>65535，那么高位会舍去，即为70000-65536=4464
         //等于是来了个循环，两次中断间ARR的增量还是5000。所以为了波形的稳定，初始化时，必须要有TIM_Period = 65535
     }
     else if (TIM_GetITStatus(TIM3, TIM_IT_CC2) != RESET)
     {
         TIM_ClearITPendingBit(TIM3, TIM_IT_CC2);

         /* LED3 toggling with frequency = 9.15 Hz */
         STM_EVAL_LEDToggle(LED3);//PD13取反
         capture = TIM_GetCapture2(TIM3);
         TIM_SetCompare2(TIM3, capture + CCR2_Val);
     }
     else if (TIM_GetITStatus(TIM3, TIM_IT_CC3) != RESET)
     {
         TIM_ClearITPendingBit(TIM3, TIM_IT_CC3);

         /* LED5 toggling with frequency = 18.31 Hz */
         STM_EVAL_LEDToggle(LED5);//PD14取反
         capture = TIM_GetCapture3(TIM3);
         TIM_SetCompare3(TIM3, capture + CCR3_Val);
     }
     else
     {
         TIM_ClearITPendingBit(TIM3, TIM_IT_CC4);

         /* LED6 toggling with frequency = 36.62 Hz */
         STM_EVAL_LEDToggle(LED6);//PD15取反
         capture = TIM_GetCapture4(TIM3);
         TIM_SetCompare4(TIM3, capture + CCR4_Val);
     }
 }


 /******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE****/

ReadMe.txt

/**
  @page TIM_TimeBase TIM_TimeBase
  
  @verbatim
  ******************************************************************************
  * @file    TIM_TimeBase/readme.txt
  * @author  MCD Application Team
  * @version V1.0.0
  * @date    19-September-2011
  * @brief   Description of the TIM Time Base example.
  ******************************************************************************
  * THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
  * WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE
  * TIME. AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY
  * DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING
  * FROM THE CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE
  * CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
  ******************************************************************************
   @endverbatim


@par Example Description 


This example shows how to configure the TIM peripheral in Output Compare Timing 
mode with the corresponding Interrupt requests for each channel in order to generate
4 different time bases.


The TIM3CLK frequency is set to SystemCoreClock / 2 (Hz), to get TIM3 counter 
clock at 500 KHz so the Prescaler is computed as following:
   - Prescaler = (TIM3CLK / TIM3 counter clock) - 1


SystemCoreClock is set to 168 MHz for STM32F4xx Devices Revision A.


The TIM3 CC1 register value is equal to 54618, 
CC1 update rate = TIM3 counter clock / CCR1_Val = 9.154 Hz,
so the TIM3 Channel 1 generates an interrupt each 109.2ms


The TIM3 CC2 register is equal to 27309, 
CC2 update rate = TIM3 counter clock / CCR2_Val = 18.31 Hz
so the TIM3 Channel 2 generates an interrupt each 54.6ms


The TIM3 CC3 register is equal to 13654, 
CC3 update rate = TIM3 counter clock / CCR3_Val = 36.62 Hz
so the TIM3 Channel 3 generates an interrupt each 27.3ms


The TIM3 CC4 register is equal to 6826, 
CC4 update rate = TIM3 counter clock / CCR4_Val =  73.25 Hz
so the TIM3 Channel 4 generates an interrupt each 13.65ms.


When the counter value reaches the Output compare registers values, the Output 
Compare interrupts are generated and, in the handler routine, 4 pins(PD.12, PD.13,
PD.14 and PD.15) are toggled with the following frequencies: 


//引脚输出的频率
- PD.12:  4.57 Hz (CC1)
- PD.13:  9.15 Hz (CC2)
- PD.14: 18.31 Hz (CC3) 
- PD.15: 36.62 Hz (CC4)


@par Directory contents 


  - TIM_TimeBase/stm32f4xx_conf.h     Library Configuration file
  - TIM_TimeBase/stm32f4xx_it.c       Interrupt handlers
  - TIM_TimeBase/stm32f4xx_it.h       Interrupt handlers header file
  - TIM_TimeBase/main.c               Main program 
  - TIM_TimeBase/system_stm32f4xx.c   STM32F4xx system clock configuration file
  
 


@par Hardware and Software environment 


  - This example runs on STM32F4xx Devices Revision A.
  
  - This example has been tested with STM32F4-Discovery (MB997) RevA and can be
    easily tailored to any other development board.
    


  - STM32F4-Discovery  
    - Use LED4, LED3, LED5 and LED6 connected respectively to PD.12, PD.13,D.14 
    and PD.15 pins and connect them on an oscilloscope to show the different 
    Time Base signals.  


@par How to use it ? 


In order to make the program work, you must do the following :


 + EWARM
    - Open the TIM_TimeBase.eww workspace 
    - Rebuild all files: Project->Rebuild all
    - Load project image: Project->Debug
    - Run program: Debug->Go(F5)


 + MDK-ARM
    - Open the TIM_TimeBase.uvproj project
    - Rebuild all files: Project->Rebuild all target files
    - Load project image: Debug->Start/Stop Debug Session
    - Run program: Debug->Run (F5)    


 + TASKING
    - Open TASKING toolchain.
    - Click on File->Import, select General->'Existing Projects into Workspace' 
      and then click "Next". 
    - Browse to  TASKING workspace directory and select the project "TIM_TimeBase"   
    - Rebuild all project files: Select the project in the "Project explorer" 
      window then click on Project->build project menu.
    - Run program: Select the project in the "Project explorer" window then click 
      Run->Debug (F11)


 + TrueSTUDIO
    - Open the TrueSTUDIO toolchain.
    - Click on File->Switch Workspace->Other and browse to TrueSTUDIO workspace 
      directory.
    - Click on File->Import, select General->'Existing Projects into Workspace' 
      and then click "Next". 
    - Browse to the TrueSTUDIO workspace directory and select the project "TIM_TimeBase" 
    - Rebuild all project files: Select the project in the "Project explorer" 
      window then click on Project->build project menu.
    - Run program: Select the project in the "Project explorer" window then click 
      Run->Debug (F11)
   
 *

© COPYRIGHT 2011 STMicroelectronics

 */