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STM32f4 different timers

Question asked by stone.jorge on Oct 8, 2015
Latest reply on Oct 8, 2015 by stone.jorge
Hi,
I'm working with stm32f4-disco. I made a code that works well: the micro waits for an external interrupt, and when receives the interrupt it makes pulses of 40kHz with a duration of 1 ms. Now, I wanted to configure another timer so that it makes an output of 100Hz in a pin. In this case I try to configure TIM1 in PA8 but I tried also TIM14 in PA7. The problem is that the pin doesn't make output. Here's the code:

// Assumptions per system_stm32f4xx.c CPU @ 168 MHz, APB2 @ 84 MHz (/2), APB1 @ 42 MHz (/4)
 
int modulatingcount=0;
 
/**************************************************************************/
 
void RCC_Configuration(void)
{
  /* GPIO's clock enable */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
 
  /* Enable SYSCFG clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);
 
  /* TIM's clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM13, ENABLE);
 
 
}
 
/**************************************************************************/
 
void GPIO_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
 
  /* GPIOA Configuration: TIM13 CH1 (PA6) */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
 
  /*GPIOA Configuration: TIM1 CH1 (PA8)*/
   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
   GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
   GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
   GPIO_Init(GPIOA, &GPIO_InitStructure);
 
   /* Connect TIM1 pins to AF */
   GPIO_PinAFConfig(GPIOA, GPIO_PinSource8, GPIO_AF_TIM1);
 
  /* Connect TIM13 pins to AF */
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_TIM13);
 
 
  /* Configure PA0 pin as input floating (EXTI, arduino)*/
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
}
 
/**************************************************************************/
 
void NVIC_Configuration(void)
{
  NVIC_InitTypeDef NVIC_InitStructure;
 
  /* Enable the TIM13 global Interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = TIM8_UP_TIM13_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
 
}
 
/**************************************************************************/
 
uint32_t Period;
 
void TIM13_Configuration(void)
{
  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
  TIM_OCInitTypeDef  TIM_OCInitStructure;
 
  //Periode en ticks, (168Mhz/2)/40kHz
 
  Period = (SystemCoreClock / 2) / 40000; // 40 KHz, from APB1 clock *2, nominally 84 MHz
 
  /* Time base configuration */
  TIM_TimeBaseStructure.TIM_Prescaler = 0;
  TIM_TimeBaseStructure.TIM_Period = Period - 1;
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInit(TIM13, &TIM_TimeBaseStructure);
 
  /* PWM1 Mode configuration: Channel1 */
  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse =  Period / 2; // 50/50 duty
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
 
  TIM_OC1Init(TIM13, &TIM_OCInitStructure);
  TIM_OC1PreloadConfig(TIM13, TIM_OCPreload_Enable);
 
  /* TIM Interrupts enable */
  TIM_ITConfig(TIM13, TIM_IT_Update, ENABLE);
 
}
 
/**************************************************************************/
#define TimerON 40
 
 
void TIM8_UP_TIM13_IRQHandler(void) // 40KHz
{
  if (TIM_GetITStatus(TIM13, TIM_IT_Update) != RESET) // Validate source
  {
    TIM_ClearITPendingBit(TIM13, TIM_IT_Update); // Clear source
 
    modulatingcount++;
 
    if (modulatingcount > TimerON){
        TIM_Cmd(TIM13, DISABLE);
        }
  }
}
 
void TIM1_Configuration(void)
{
  TIM_OCInitTypeDef  TIM_OCInitStructure;
  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
  uint16_t Period;
 
  Period = 1000000 / 100; // 100 Hz for 1MHz prescaled
 
  /* Time base configuration */
  TIM_TimeBaseStructure.TIM_Prescaler = (SystemCoreClock / 1000000)  - 1;
  TIM_TimeBaseStructure.TIM_Period = Period - 1;
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);
 
  /* Enable TIM1 Preload register on ARR */
  TIM_ARRPreloadConfig(TIM1, ENABLE);
 
  /* TIM PWM1 Mode configuration */
  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = Period / 2; // 50%
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
 
  /* Output Compare PWM1 Mode configuration: Channel1 PA.08 */
  TIM_OC1Init(TIM1, &TIM_OCInitStructure);
  TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Enable);
 
    /* TIM1 Main Output Enable */
    TIM_CtrlPWMOutputs(TIM1, ENABLE);
 
  /* TIM1 enable counter */
  TIM_Cmd(TIM1, ENABLE);
}
 
/**************************************************************************************/
 
static void EXTILine0_Config(void);
void GPIO_Initialize(void);
 
 
GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
 
 
static void EXTILine0_Config(void)
{
 
 EXTI_InitTypeDef EXTI_InitStructure;
// Connect EXTI Line0 to PA0 pin
 SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource0);
 
// Configure EXTI Line0
 EXTI_InitStructure.EXTI_Line = EXTI_Line0;
 EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
 EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;
 EXTI_InitStructure.EXTI_LineCmd = ENABLE;
 EXTI_Init(&EXTI_InitStructure);
 
// Enable and set EXTI Line0 Interrupt to the lowest priority
 NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;
 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x0F;
 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
 NVIC_Init(&NVIC_InitStructure);
}
 
void EXTI0_IRQHandler(void)
{
 if(EXTI_GetITStatus(EXTI_Line0) != RESET)
 {
     //Toggle LED
     STM_EVAL_LEDToggle(LED4);
     modulatingcount=0;
     TIM_Cmd(TIM13, ENABLE);
 
 
 // Clear the EXTI line 0 pending bit
 EXTI_ClearITPendingBit(EXTI_Line0);
 }
}
 
/**************************************************************************************/
 
int main(void)
{
  RCC_Configuration();
 
  NVIC_Configuration();
 
  GPIO_Configuration();
 
  TIM1_Configuration();
 
  TIM13_Configuration();
 
  EXTILine0_Config();
 
  STM_EVAL_LEDInit(LED4);
 
  STM_EVAL_LEDOn(LED4);
 
 
while(1){
    }
}


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