frequency capture

[c10390377]

Posted on June 06, 2013 at 00:56

im trying to capture frequency from 0 to 100khz optical encoder . and here is my code doesn't seem to work. any help please im new to micro controller.

#include ''stm32f10x.h''#include ''stm32f10x_tim.h''#include ''stm32f10x_rcc.h''#include ''stm32f10x_gpio.h''#include ''misc.h''unsigned int IC2Value, DutyCycle ,Frequency ;    void RCC_Configuration(void)    {  RCC_APB1PeriphClockCmd (RCC_APB1Periph_TIM3, ENABLE); // clock configuration //RCC_APB2PeriphClockCmd (RCC_APB2Periph_GPIOA, ENABLE);    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC | RCC_APB2Periph_AFIO, ENABLE);    }    void GPIO_Configuration(void)    { // GPIO configuration GPIO_InitTypeDef   GPIO_InitStructure; GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOC, &GPIO_InitStructure); GPIO_PinRemapConfig( GPIO_FullRemap_TIM3, ENABLE );        // Map TIM3 to GPIOC    }    void NVIC_Configuration(void)    { // NVIC configuration NVIC_InitTypeDef NVIC_InitStructure; NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init (& NVIC_InitStructure);    }    void TIM3_Configuration(void)    { // TIMER configuration //TTIM_ICInitStructure (& TIM_ICInitStructure); TIM_ICInitTypeDef  TIM_ICInitStructure; TIM_ICInitStructure.TIM_Channel = TIM_Channel_2; // channel selection TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; // rising edge of the trigger TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; // correspondence between the pin and register TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; // input prescaler. Control in the number of input cycle time capture, if //TIM_ICInit(TIM3 , &TIM_ICInitStructure); /* Input signal frequency has not changed, will not change the measured period. Such as divided by 4, * each of the four input period before doing a capture, *so that the input signal does not change frequently, *Can reduce the frequency and software are constantly interrupted. */ TIM_ICInitStructure.TIM_ICFilter = 0x0; // filter settings, go through several cycles transition finds the stable waveform 0x0 to 0xF TIM_PWMIConfig (TIM3, & TIM_ICInitStructure); // the parameter configuration TIM peripheral information TIM_SelectInputTrigger (TIM3, TIM_TS_TI2FP2); // select IC2 always trigger source TIM_SelectSlaveMode (TIM3, TIM_SlaveMode_Reset) ;// TIM mode: update event triggers the rising edge of the signal to re-initialize the counter and trigger register TIM_SelectMasterSlaveMode (TIM3, TIM_MasterSlaveMode_Enable); // start the timer passive trigger TIM_Cmd (TIM3, ENABLE); // start TIM3 TIM_ITConfig (TIM3, TIM_IT_CC2, ENABLE); // Open interrupt    }int main(void){  RCC_Configuration();  GPIO_Configuration();  TIM3_Configuration();  NVIC_Configuration(); void TIM3_IRQHandler (void) { IC2Value = TIM_GetCapture2 (TIM3); // read IC2 capture register, the count value is the PWM cycle if (IC2Value != 0) { DutyCycle = (TIM_GetCapture1 (TIM3) * 100) / IC2Value; // read IC1 to capture the value of the register, and calculate the duty cycle Frequency = 24000000 / IC2Value; // calculate the PWM frequency. } else { DutyCycle = 0; Frequency = 0; } TIM_ClearITPendingBit (TIM3, TIM_IT_CC2); // clear interrupt pending bit TIM } while(1) {}}