帮我写一个GD32定时器3四通道PWM程序

当然，我可以为您提供一个GD32定时器3四通道PWM程序的示例。以下是一个基本的程序框架：

#include "gd32f10x.h"

#define TIMER_PRESCALER     71
#define TIMER_PERIOD        999

void timer3_pwm_init(void)
{
    /* 使能定时器3时钟 */
    rcu_periph_clock_enable(RCU_TIMER3);
    
    /* 配置定时器3为PWM模式1 */
    timer_oc_parameter_struct timer_ocinitpara;
    timer_parameter_struct timer_initpara;
    
    timer_deinit(TIMER3);
    
    timer_initpara.prescaler         = TIMER_PRESCALER;
    timer_initpara.alignedmode       = TIMER_COUNTER_EDGE;
    timer_initpara.counterdirection  = TIMER_COUNTER_UP;
    timer_initpara.period            = TIMER_PERIOD;
    timer_initpara.clockdivision     = TIMER_CKDIV_DIV1;
    timer_initpara.repetitioncounter = 0;
    timer_init(TIMER3, &timer_initpara);
    
    /* 配置通道1、2、3和4为PWM输出模式 */
    timer_ocinitpara.outputstate  = TIMER_CCX_ENABLE;
    timer_ocinitpara.outputnstate = TIMER_CCXN_DISABLE;
    timer_ocinitpara.ocpolarity   = TIMER_OC_POLARITY_HIGH;
    timer_ocinitpara.ocnpolarity  = TIMER_OCN_POLARITY_HIGH;
    timer_ocinitpara.ocidlestate  = TIMER_OC_IDLE_STATE_LOW;
    timer_ocinitpara.ocnidlestate = TIMER_OCN_IDLE_STATE_LOW;
    
    timer_channel_output_config(TIMER3, TIMER_CH_1, &timer_ocinitpara);
    timer_channel_output_config(TIMER3, TIMER_CH_2, &timer_ocinitpara);
    timer_channel_output_config(TIMER3, TIMER_CH_3, &timer_ocinitpara);
    timer_channel_output_config(TIMER3, TIMER_CH_4, &timer_ocinitpara);
    
    /* 配置通道1、2、3和4的PWM占空比 */
    timer_channel_output_pulse_value_config(TIMER3, TIMER_CH_1, 0);
    timer_channel_output_mode_config(TIMER3, TIMER_CH_1, TIMER_OC_MODE_PWM1);
    timer_channel_output_shadow_config(TIMER3, TIMER_CH_1, TIMER_OC_SHADOW_DISABLE);
    
    timer_channel_output_pulse_value_config(TIMER3, TIMER_CH_2, 0);
    timer_channel_output_mode_config(TIMER3, TIMER_CH_2, TIMER_OC_MODE_PWM1);
    timer_channel_output_shadow_config(TIMER3, TIMER_CH_2, TIMER_OC_SHADOW_DISABLE);
    
    timer_channel_output_pulse_value_config(TIMER3, TIMER_CH_3, 0);
    timer_channel_output_mode_config(TIMER3, TIMER_CH_3, TIMER_OC_MODE_PWM1);
    timer_channel_output_shadow_config(TIMER3, TIMER_CH_3, TIMER_OC_SHADOW_DISABLE);
    
    timer_channel_output_pulse_value_config(TIMER3, TIMER_CH_4, 0);
    timer_channel_output_mode_config(TIMER3, TIMER_CH_4, TIMER_OC_MODE_PWM1);
    timer_channel_output_shadow_config(TIMER3, TIMER_CH_4, TIMER_OC_SHADOW_DISABLE);
    
    /* 使能定时器3 */
    timer_enable(TIMER3);
}

int main(void)
{
    /* 初始化定时器3的PWM功能 */
    timer3_pwm_init();
    
    while (1) {
        // 在这里可以进行其他操作
    }
}

请注意，上述代码仅提供了一个基本的程序框架，您可能需要根据自己的需求进行修改和补充。希望对您有所帮助！如有任何问题，请随时提问。