Timer 2 CC ISR is triggered twice!?

[kounst]

Posted on September 28, 2009 at 19:42

Timer 2 CC ISR is triggered twice!?

[kounst]

Posted on May 17, 2011 at 13:22

yes I did.

The ISR is only called twice after each edge- so I think the problem can't be related to the interrupt flag.

[guyvo67]

Posted on May 17, 2011 at 13:22

kounst,

Did you reset you CC flag in the interrupt routine like:

TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);

?

[kounst]

Posted on May 17, 2011 at 13:22

Hello,

I'm trying to measure the PWM signal of a rc receiver.

The falling edge of the signal triggers the tim 2 cc isr.

My problem is that for some reason the ISR is triggered again only 2usec later. There are no rising nor falling edges for at least 1msec.

Thanks for any help!

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

* Function Name : main

* Description : Main program

* Input : None

* Output : None

* Return : None

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

int main(void)

{

#ifdef DEBUG

debug();

#endif

/* System clocks configuration -----------*/

RCC_Configuration();

/* NVIC configuration ---*/

NVIC_Configuration();

/* GPIO configuration */

GPIO_Configuration();

/* TIM2 Configuration */

TIM2_Configuration();

while (1)

{

}

}

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

* Function Name : GPIO_Configuration

* Description : Configure the used I/O ports pin

* Input : None

* Output : None

* Return : None

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

void GPIO_Configuration()

{

GPIO_InitTypeDef GPIO_InitStructure;

/* Configure capture compare input for pwm measurement */

/* TIM2 channel 2 pin (PA.01) configuration */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_Init(GPIOA, &GPIO_InitStructure);

/* Toggle Pin */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;

GPIO_Init(GPIOA, &GPIO_InitStructure);

}

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

* Function Name : TIM2_Confgureation()

* Description :

* Input : None

* Output : None

* Return : None

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

void TIM2_Configuration(void)

{

TIM_ICInitTypeDef TIM_ICInitStructure;

//TIM_ICInitStructure.TIM_ICMode = TIM_ICMode_ICAP;

TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;

TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Falling;

TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;

TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;

TIM_ICInitStructure.TIM_ICFilter = 0x0;

TIM_ICInit(TIM2, &TIM_ICInitStructure);

TIM_SelectInputTrigger(TIM2, TIM_TS_TI2FP2);

TIM_InternalClockConfig(TIM2);

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

TIM_TimeBaseStructure.TIM_Period = 0xFFFF;

TIM_TimeBaseStructure.TIM_Prescaler = 72;

TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;

TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

TIM_TimeBaseInit(TIM2, & TIM_TimeBaseStructure);

/* TIM enable counter */

TIM_Cmd(TIM2, ENABLE);

/* Enable the CC2 Interrupt Request */

TIM_ITConfig(TIM2, TIM_IT_CC2, ENABLE);

}

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

* Function Name : RCC_Configuration

* Description : Configures the different system clocks.

* Input : None

* Output : None

* Return : None

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

void RCC_Configuration(void)

{

/* RCC system reset(for debug purpose) */

RCC_DeInit();

/* Enable HSE */

RCC_HSEConfig(RCC_HSE_ON);

/* Wait till HSE is ready */

HSEStartUpStatus = RCC_WaitForHSEStartUp();

if(HSEStartUpStatus == SUCCESS)

{

/* Enable Prefetch Buffer */

FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);

/* Flash 2 wait state */

FLASH_SetLatency(FLASH_Latency_2);

/* HCLK = SYSCLK */

RCC_HCLKConfig(RCC_SYSCLK_Div1);

/* PCLK2 = HCLK */

RCC_PCLK2Config(RCC_HCLK_Div1);

/* PCLK1 = HCLK/2 */

RCC_PCLK1Config(RCC_HCLK_Div2);

/* PLLCLK = 8MHz * 9 = 72 MHz */

RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9);

/* Enable PLL */

RCC_PLLCmd(ENABLE);

/* Wait till PLL is ready */

while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)

{

}

/* Select PLL as system clock source */

RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);

/* Wait till PLL is used as system clock source */

while(RCC_GetSYSCLKSource() != 0x08)

{

}

}

/* Enable peripheral clocks ----------------*/

/* GPIOB Periph clock enable */

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

/* TIM2 clock enable */

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

}

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

* Function Name : NVIC_Configuration

* Description : Configures Vector Table base location.

* Input : None

* Output : None

* Return : None

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

void NVIC_Configuration(void)

{

NVIC_InitTypeDef NVIC_InitStructure;

#ifdef VECT_TAB_RAM

/* Set the Vector Table base location at 0x20000000 */

NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);

#else /* VECT_TAB_FLASH */

/* Set the Vector Table base location at 0x08000000 */

NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);

#endif

/* Enable the TIM2 global Interrupt */

NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQChannel;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure);

}

[ This message was edited by: kounst on 01-09-2009 21:19 ]

[kounst]

Posted on May 17, 2011 at 13:22

Hi,

yes I solved it!

I figured out that if I turn off my laptop everything works fine.

So I added a Schmitt Trigger. Problem solved!

Regards,

[smithdexter]

Posted on May 17, 2011 at 13:22

Kounst,

Did you find a reason for this as I am seeing this now?