Posted on August 28, 2014 at 01:04Hi:
I am using the STM3221G-EVAL board and TIM example from STM32F2xx_StdPeriph_Lib. I modified the original example so I can use PG15 input.
There is a pushbutton connected to PG15 on the eval board.
When I press the pushbutton nothing happens. The system never goes through TIM1_CC_IRQHandler. what would be the problem?
Thanks.
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_stm32f2xx.s) before to branch to application main.
To reconfigure the default setting of SystemInit() function, refer to
system_stm32f2xx.c file
*/
/* TIM1 Configuration */
GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
TIM_ICInitTypeDef TIM_ICInitStructure;
/* TIM1 clock enable */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
/* GPIOG clock enable */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOG, ENABLE);
/* TIM1 channel 2 pin (PG.15) configuration */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_15;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOG, &GPIO_InitStructure);
/* Connect TIM pins to AF1 */
GPIO_PinAFConfig(GPIOG, GPIO_PinSource15, GPIO_AF_TIM1);
/* Enable the TIM1 global Interrupt */
NVIC_InitStructure.NVIC_IRQChannel = TIM1_CC_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
/* TIM1 configuration: Input Capture mode ---------------------
The external signal is connected to TIM1 CH2 pin (PG.15)
The Rising edge is used as active edge,
The TIM1 CCR2 is used to compute the frequency value
------------------------------------------------------------ */
TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;
TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV8;
TIM_ICInitStructure.TIM_ICFilter = 0x0;
TIM_ICInit(TIM1, &TIM_ICInitStructure);
/* TIM enable counter */
TIM_Cmd(TIM1, ENABLE);
/* Enable the CC2 Interrupt Request */
TIM_ITConfig(TIM1, TIM_IT_CC2, ENABLE);
while (1);
}
void TIM1_CC_IRQHandler(void)
{
if(TIM_GetITStatus(TIM1, TIM_IT_CC2) == SET)
{
/* Clear TIM1 Capture compare interrupt pending bit */
TIM_ClearITPendingBit(TIM1, TIM_IT_CC2);
if(CaptureNumber == 0)
{
/* Get the Input Capture value */
IC3ReadValue1 = TIM_GetCapture2(TIM1);
CaptureNumber = 1;
}
else if(CaptureNumber == 1)
{
/* Get the Input Capture value */
IC3ReadValue2 = TIM_GetCapture2(TIM1);
/* Capture computation */
if (IC3ReadValue2 > IC3ReadValue1)
{
Capture = (IC3ReadValue2 - IC3ReadValue1);
}
else if (IC3ReadValue2 < IC3ReadValue1)
{
Capture = ((0xFFFF - IC3ReadValue1) + IC3ReadValue2);
}
else
{
Capture = 0;
}
/* Frequency computation */
TIM1Freq = (uint32_t) SystemCoreClock / Capture;
CaptureNumber = 0;
}
}
}
#input-capture #stm3221-eval
