利用GD32F470的定时器实现频率和占空比测试

1）main函数代码如下：

#include "gd32f4xx.h"
#include <stdio.h>
#include "gd32f470i_eval.h"
#include "systick.h"

void TIM_PwmInit(void)
{
    rcu_periph_clock_enable(RCU_GPIOA);

    /* PWM输出管脚为复用推挽模式 */
    gpio_mode_set(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE,GPIO_PIN_1);
    gpio_output_options_set(GPIOA, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ,GPIO_PIN_1);
    gpio_af_set(GPIOA, GPIO_AF_1, GPIO_PIN_1);

    /* PWM输入管脚为浮空输入模式 */
    gpio_mode_set(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE,GPIO_PIN_6);
    gpio_output_options_set(GPIOA, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ,GPIO_PIN_6);
    gpio_af_set(GPIOA, GPIO_AF_1, GPIO_PIN_6);

    /* TIMER1初始化 */
    timer_oc_parameter_struct timer_ocintpara = {0};
    timer_parameter_struct timer_initpara = {0};

    rcu_periph_clock_enable(RCU_TIMER1);

    timer_deinit(TIMER1);

    timer_initpara.prescaler         = (108 - 1);  // 预分频：108MHz / 108 = 1MHz
    timer_initpara.alignedmode       = TIMER_COUNTER_EDGE;  // 边沿对齐计数
    timer_initpara.counterdirection  = TIMER_COUNTER_UP;  // 向上计数
    timer_initpara.period            = (1000 - 1);  // 周期：1MHz / 1000 = 1000Hz  注: 下面设置的占空比必须小于等于period,否则错误;
    timer_init(TIMER1, &timer_initpara);

    /* 配置所有通道为PWM模式0 */
    timer_ocintpara.ocpolarity   = TIMER_OC_POLARITY_HIGH;  // 通道输出极性高，即高电平有效
    timer_ocintpara.outputstate  = TIMER_CCX_ENABLE;  // 使能输出通道
    timer_ocintpara.ocidlestate  = TIMER_OC_IDLE_STATE_LOW;  // 输出通道空闲低电平

    timer_channel_output_config(TIMER1,TIMER_CH_1, &timer_ocintpara);

    /* 配置通道1为25%占空比 */
    timer_channel_output_pulse_value_config(TIMER1, TIMER_CH_1, (250 - 1));  // 250 / 1000 = 25%
    timer_channel_output_mode_config(TIMER1,TIMER_CH_1, TIMER_OC_MODE_PWM0);  // 配置为PWM模式0
    timer_channel_output_shadow_config(TIMER1,TIMER_CH_1, TIMER_OC_SHADOW_DISABLE);  // 关闭输出影子

    timer_auto_reload_shadow_enable(TIMER1);  // 使能重装载影子
    timer_enable(TIMER1);  // 使能定时器1

    /* 初始化TIMER2 */
    timer_ic_parameter_struct timer_icinitpara = {0};
    
    rcu_periph_clock_enable(RCU_TIMER2);

    timer_deinit(TIMER2);

    timer_initpara.prescaler         = (108 - 1);  // 预分频：108MHz / 108 = 1MHz
    timer_initpara.alignedmode       = TIMER_COUNTER_EDGE;  // 边沿对齐计数
    timer_initpara.counterdirection  = TIMER_COUNTER_UP;  // 向上计数模式
    timer_initpara.period            = (65536 - 1);  // 周期最好设置为最高，以免计数器溢出
    timer_initpara.clockdivision     = TIMER_CKDIV_DIV1;  // 输入时钟1分频
    timer_init(TIMER2,&timer_initpara);

    timer_icinitpara.icpolarity  = TIMER_IC_POLARITY_RISING;  // 输入极性为上升沿，即上升沿有效
    timer_icinitpara.icselection = TIMER_IC_SELECTION_DIRECTTI;  // 输入捕获通道连接至CIx
    timer_icinitpara.icprescaler = TIMER_IC_PSC_DIV1;  // 时钟1分频
    timer_icinitpara.icfilter    = 0x0;
    timer_input_pwm_capture_config(TIMER2, TIMER_CH_0, &timer_icinitpara);

    timer_input_trigger_source_select(TIMER2, TIMER_SMCFG_TRGSEL_CI0FE0);  // 输入触发源为通道0
    timer_slave_mode_select(TIMER2, TIMER_SLAVE_MODE_RESTART);  // 从模式选择为复位模式
    timer_master_slave_mode_config(TIMER2, TIMER_MASTER_SLAVE_MODE_ENABLE);  // 使能从模式

    timer_auto_reload_shadow_enable(TIMER2);  // 使能重装载影子
    
    nvic_priority_group_set(NVIC_PRIGROUP_PRE4_SUB0);  // 抢占优先级4位，响应优先级0位
    nvic_irq_enable(TIMER2_IRQn, 1, 0);  // 使能中断服务，抢占优先级为1
    
    timer_interrupt_flag_clear(TIMER2, TIMER_INT_CH0);  // 清除通道0中断标志位
    timer_interrupt_enable(TIMER2, TIMER_INT_CH0);  // 使能通道0中断

    timer_enable(TIMER2);  // 使能定时器2
}

int fputc(int ch, FILE *f)
{
    usart_data_transmit(EVAL_COM0, (uint8_t)ch);
    while (RESET == usart_flag_get(EVAL_COM0, USART_FLAG_TBE));
    return ch;
}

extern __IO uint16_t dutycycle;
extern __IO uint16_t frequency;
int main(void)
{
    systick_config();
    TIM_PwmInit();
    gd_eval_com_init(EVAL_COM0);

    while(1)
    {
        printf("dutycycle: %d%%, frequency: %dHz\n", dutycycle, frequency);
        delay_1ms(1000);
    }
}

2）中断函数如下所示(gd32f4xx_it.c)：

uint32_t ic1value = 0, ic2value = 0;
__IO uint16_t dutycycle = 0;
__IO uint16_t frequency = 0;

void TIMER2_IRQHandler(void)
{
    if(SET == timer_interrupt_flag_get(TIMER2, TIMER_INT_CH0))
    {
        timer_interrupt_flag_clear(TIMER2, TIMER_INT_CH0);  // 清除中断标志位
        
        ic1value = timer_channel_capture_value_register_read(TIMER2, TIMER_CH_0) + 1;

        if(0 != ic1value)
        {
            
            ic2value = timer_channel_capture_value_register_read(TIMER2, TIMER_CH_1) + 1;

            dutycycle = (ic2value * 100) / ic1value;  // 计算占空比
            frequency = (float)1000000 / ic1value;  // 计算频率
        }
        else
        {
            dutycycle = 0;
            frequency = 0;
        }
    }
}

3）测试方法：PA6与PA1用镊子短接，用示波器连接信号，串口打开，如下图所示：

从上图可知道，频率是927赫兹，（目标代码应该是1000HZ），有一定误差，

上图示波器测试的占空比是25%；
4）打开串口，查看GD32F470测试的结果，如下图所示：

原文地址：https://blog.csdn.net/qq_30143193/article/details/139865385

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