STM32F4-Discovery TIM4 3-Phase Output PD12, PD13 and PD14

#include "stm32f4xx.h"

 

//******************************************************************************

 

void RCC_Configuration(void)

{

  /* enable peripheral clock for TIM4 */

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);

 

  /* GPIOD clock enable */

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);

}

 

//******************************************************************************

 

void GPIO_Configuration(void)

{

  GPIO_InitTypeDef GPIO_InitStructure;

 

  /* GPIOD Configuration:  TIM4 on PD12/PD13/PD14 LED */

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12 | GPIO_Pin_13 | GPIO_Pin_14;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;

  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;

  GPIO_Init(GPIOD, &GPIO_InitStructure);

 

  /* Connect TIM4 pin  */

  GPIO_PinAFConfig(GPIOD, GPIO_PinSource12, GPIO_AF_TIM4); // PD12 TIM4_CH1

  GPIO_PinAFConfig(GPIOD, GPIO_PinSource13, GPIO_AF_TIM4); // PD13 TIM4_CH2

  GPIO_PinAFConfig(GPIOD, GPIO_PinSource14, GPIO_AF_TIM4); // PD14 TIM4_CH3

}

 

//******************************************************************************

 

void TIM4_Configuration(void)

{

  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;

  TIM_OCInitTypeDef  TIM_OCInitStructure;

  int Prescaler, Period;

 

  Prescaler = ((SystemCoreClock / 2) / 20000); // 20 KHz timebase, assumes APB1 H/4 TIMCLK4 H/2

 

  Period = 20000 / 1; // 1 Hz - 1 second on, 1 second off duty

 

  // The toggle halves the frequency, a phase shift of 90 degrees (1/4) is 180 degrees (1/2)

 

  /* Time base configuration */

  TIM_TimeBaseStructure.TIM_Period = Period - 1;

  TIM_TimeBaseStructure.TIM_Prescaler = Prescaler - 1;

  TIM_TimeBaseStructure.TIM_ClockDivision = 0;

  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

  TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);

 

  /* Output Compare Toggle Mode configuration: Channel 1, 2 & 3 */

  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle;

  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;

  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

 

  TIM_OCInitStructure.TIM_Pulse = (Period / 6); // CH1 60 + 0 Degrees

  TIM_OC1Init(TIM4, &TIM_OCInitStructure);

 

  TIM_OCInitStructure.TIM_Pulse = (Period / 6) + (Period / 3); // CH2 60 + 120 Degrees

  TIM_OC2Init(TIM4, &TIM_OCInitStructure);

 

  TIM_OCInitStructure.TIM_Pulse = (Period / 6) + ((Period * 2) / 3); // CH3 60 + 240 Degrees

  TIM_OC3Init(TIM4, &TIM_OCInitStructure);

 

  /* TIM4 enable counter */

  TIM_Cmd(TIM4, ENABLE);

}

 

//******************************************************************************

 

int main(void)

{

  RCC_Configuration();

 

  GPIO_Configuration();

 

  TIM4_Configuration();

 

  while(1); /* Infinite loop */

}