GD32F3x0_Firmware_Library/Examples/TIMER/TIMER2_inputcapture/main.c

/*!
    \file  main.c
    \brief TIMER2 input capture demo
*/

/*
    Copyright (C) 2017 GigaDevice

    2017-06-06, V1.0.0, firmware for GD32F3x0
*/

#include "gd32f3x0.h"
#include <stdio.h>
#include "gd32f3x0_eval.h"

void gpio_configuration(void);
void timer_configuration(void);
void nvic_configuration(void);
int fputc(int ch, FILE *f);

/* retarget the C library printf function to the USART */
int fputc(int ch, FILE *f)
{
    usart_data_transmit(EVAL_COM1, (uint8_t) ch);
    while (RESET == usart_flag_get(EVAL_COM1,USART_FLAG_TC));
    return ch;
}

/*!
    \brief      configure the GPIO ports
    \param[in]  none
    \param[out] none
    \retval     none
  */
void gpio_configuration(void)
{
    rcu_periph_clock_enable(RCU_GPIOB);

    /*configure PB4 (TIMER2 CH0) as alternate function*/
    gpio_mode_set(GPIOB, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO_PIN_4);
    gpio_output_options_set(GPIOB, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ,GPIO_PIN_4);

    gpio_af_set(GPIOB, GPIO_AF_1, GPIO_PIN_4);
}

/*!
    \brief      configure the nested vectored interrupt controller
    \param[in]  none
    \param[out] none
    \retval     none
  */
void nvic_configuration(void)
{
    nvic_priority_group_set(NVIC_PRIGROUP_PRE1_SUB3);
    nvic_irq_enable(TIMER2_IRQn, 1, 1);
}

/*!
    \brief      configure the TIMER peripheral
    \param[in]  none
    \param[out] none
    \retval     none
  */
void timer_configuration(void)
{
    /* TIMER2 configuration: input capture mode -------------------
    the external signal is connected to TIMER2 CH0 pin (PB4)
    the rising edge is used as active edge
    the TIMER2 CH0CV is used to compute the frequency value
    ------------------------------------------------------------ */
    timer_ic_parameter_struct timer_icinitpara;
    timer_parameter_struct timer_initpara;

    rcu_periph_clock_enable(RCU_TIMER2);

    timer_deinit(TIMER2);

    /* TIMER2 configuration */
#ifdef GD32F330
    timer_initpara.prescaler         = 41999;
#endif /* GD32F330 */
#ifdef GD32F350
    timer_initpara.prescaler         = 53999;
#endif /* GD32F350 */
    timer_initpara.alignedmode       = TIMER_COUNTER_EDGE;
    timer_initpara.counterdirection  = TIMER_COUNTER_UP;
    timer_initpara.period            = 65535;
    timer_initpara.clockdivision     = TIMER_CKDIV_DIV1;
    timer_initpara.repetitioncounter = 0;
    timer_init(TIMER2,&timer_initpara);

    /* TIMER2  configuration */
    /* TIMER2 CH0 input capture configuration */
    timer_icinitpara.icpolarity  = TIMER_IC_POLARITY_RISING;
    timer_icinitpara.icselection = TIMER_IC_SELECTION_DIRECTTI;
    timer_icinitpara.icprescaler = TIMER_IC_PSC_DIV1;
    timer_icinitpara.icfilter    = 0x0;
    timer_input_capture_config(TIMER2,TIMER_CH_0,&timer_icinitpara);

    /* auto-reload preload enable */
    timer_auto_reload_shadow_enable(TIMER2);
    /* clear channel 0 interrupt bit */
    timer_interrupt_flag_clear(TIMER2,TIMER_INT_CH0);
    /* channel 0 interrupt enable */
    timer_interrupt_enable(TIMER2,TIMER_INT_CH0);

    /* TIMER2 counter enable */
    timer_enable(TIMER2);
}

/*!
    \brief      main function
    \param[in]  none
    \param[out] none
    \retval     none
*/
int main(void)
{
    gpio_configuration(); 
    gd_eval_com_init(EVAL_COM1);
    nvic_configuration();
    timer_configuration();

    while (1);
}