STM32F4 Servo PWM

#include "stm32f4xx_conf.h"

#define MOTORPWMTIMER      TIM4

#define MOTORPWMTIMCLOCK    RCC_APB1Periph_TIM4

#define MOTORPWMPORTCLOCK    RCC_AHB1Periph_GPIOD

#define MOTORPWMAF         GPIO_AF_TIM4

#define MOTORPWMPORT      GPIOD

#define MOTORPWMBIT        GPIO_Pin_12

#define MOTORPWMTIMBIT      GPIO_PinSource12

// Private typedefs ----------------------------------------------------------

GPIO_InitTypeDef     GPIO_InitStructureLED;

GPIO_InitTypeDef     GPIO_InitStructureTimer;

TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;

TIM_OCInitTypeDef    TIM_OCInitStructure;

// Private variables ---------------------------------------------------------

uint32_t TimerCounterClock = 0;

uint32_t TimerOutputClock = 0;

uint16_t PrescalerValue = 0;

uint32_t PulseDurationInMicroSeconds = 0;

int i;

// the prototypes ------------------------------------------------------------

int main(void);

// Timer init for PWM

void TimerInit(void);

void Delay(__IO uint32_t nCount);

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

  */

  // /dev/tty.usbserial-A900J1T0

  // call my new USART init

  usartInit();

  // call timer init for PWM

  TimerInit();

  // Timer base configuration

  //   Don't know why, but this code has to be here (not in a seperate method)

  TIM_TimeBaseStructure.TIM_Period = (uint16_t) (TimerCounterClock / TimerOutputClock);

  TIM_TimeBaseStructure.TIM_Prescaler = (uint16_t) ((SystemCoreClock /2) / TimerCounterClock) - 1;

  TIM_TimeBaseStructure.TIM_ClockDivision = 0;

  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

  // basic timer init

  TIM_TimeBaseInit(MOTORPWMTIMER, &TIM_TimeBaseStructure);

  // configure PWM mode and duration

  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;

  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;

  TIM_OCInitStructure.TIM_Pulse = PulseDurationInMicroSeconds; // set the duty cycle / pulse here!

  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

  TIM_OC1Init(MOTORPWMTIMER, &TIM_OCInitStructure);

  TIM_OC1PreloadConfig(MOTORPWMTIMER, TIM_OCPreload_Enable);

  // preload timer config

  TIM_ARRPreloadConfig(MOTORPWMTIMER, ENABLE);

  // enable timer / counter

  TIM_Cmd(MOTORPWMTIMER, ENABLE);

  //

  //  motor pwm test ! ! !

  //

  while(1)

  {

    for (i=1; i<70; i++)

    {

      Delay(0x03FFFF);

      TIM_Cmd(MOTORPWMTIMER, DISABLE);

      PulseDurationInMicroSeconds = i;

      TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;

      TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;

      TIM_OCInitStructure.TIM_Pulse = PulseDurationInMicroSeconds; // set the duty cycle / pulse here!

      TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

      TIM_OC1Init(MOTORPWMTIMER, &TIM_OCInitStructure);

      TIM_OC1PreloadConfig(MOTORPWMTIMER, TIM_OCPreload_Enable);

      TIM_ARRPreloadConfig(MOTORPWMTIMER, ENABLE);

      TIM_Cmd(MOTORPWMTIMER, ENABLE);

    }

    for (i=70; i>2; i--)

    {

      Delay(0x03FFFF);

      TIM_Cmd(MOTORPWMTIMER, DISABLE);

      PulseDurationInMicroSeconds = i;

      TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;

      TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;

      TIM_OCInitStructure.TIM_Pulse = PulseDurationInMicroSeconds; // set the duty cycle / pulse here!

      TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

      TIM_OC1Init(MOTORPWMTIMER, &TIM_OCInitStructure);

      TIM_OC1PreloadConfig(MOTORPWMTIMER, TIM_OCPreload_Enable);

      TIM_ARRPreloadConfig(MOTORPWMTIMER, ENABLE);

      TIM_Cmd(MOTORPWMTIMER, ENABLE);

    }

  }

}

/**

  * @brief  Configure the timer for PWM.

  * @param  None

  * @retval None

  */

void TimerInit(void)

{

  // set timer frequencies

  TimerCounterClock = 1000000; //  1 MHz

  TimerOutputClock = 10000;    // 10 kHz = 100 µs period

  // set pulse duration in mili seconds (HIGH time)

  // can be up to from 0 to 99 (due to a TimerOutputClock of 10 kHz)

  PulseDurationInMicroSeconds = 50;

  // Timer clock enable

  RCC_APB1PeriphClockCmd(MOTORPWMTIMCLOCK, ENABLE);

  // Port clock enable

  RCC_AHB1PeriphClockCmd(MOTORPWMPORTCLOCK, ENABLE);

  // Set PWM Port, Pin and method

  GPIO_InitStructureTimer.GPIO_Pin = MOTORPWMBIT;

  GPIO_InitStructureTimer.GPIO_Mode = GPIO_Mode_AF;

  GPIO_InitStructureTimer.GPIO_Speed = GPIO_Speed_100MHz;

  GPIO_InitStructureTimer.GPIO_OType = GPIO_OType_PP;

  GPIO_InitStructureTimer.GPIO_PuPd = GPIO_PuPd_UP ;

  GPIO_Init(MOTORPWMPORT, &GPIO_InitStructureTimer); 

  // Connect TIM pin to AF

  GPIO_PinAFConfig(MOTORPWMPORT, MOTORPWMTIMBIT, MOTORPWMAF);

}

/**

  * @brief  Delay Function.

  * @param  nCount:specifies the Delay time length.

  * @retval None

  */

void Delay(__IO uint32_t nCount)

{

  while(nCount--)

  {

  }

}

      TIM_OC1Init(MOTORPWMTIMER, &TIM_OCInitStructure);

      TIM_OC1PreloadConfig(MOTORPWMTIMER, TIM_OCPreload_Enable);

      TIM_OC2Init(MOTORPWMTIMER, &TIM_OCInitStructure);

      TIM_OC2PreloadConfig(MOTORPWMTIMER, TIM_OCPreload_Enable);