一、初始化GPIO

使用PB1,查芯片手册对应TIM3_CH4

GPIO_InitTypeDef GPIO_InitStructure;        RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);        RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE);                GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;        GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;        GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;                GPIO_Init(GPIOB, &GPIO_InitStructure);

 

 

二、初始化TIM和PWM

　　 TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;    TIM_OCInitTypeDef TIM_OCInitStructure;    /* 周期1000 */    TIM_TimeBaseStructure.TIM_Period = 999;    /* 定时器时间间隔1微秒 */    TIM_TimeBaseStructure.TIM_Prescaler = 0;    TIM_TimeBaseStructure.TIM_ClockDivision = 0;    /* 向上计数 */    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;    /* 配置 */    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);        /* 选择PWM1模式 */    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;    /* 允许输出模式 */    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;        /* 匹配值 */    TIM_OCInitStructure.TIM_Pulse = 1000;        /* 设置小于匹配值时为高电平 */    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;    /* 使能通道1 */    TIM_OC4Init(TIM3, &TIM_OCInitStructure);            TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Enable);    TIM_ARRPreloadConfig(TIM3, ENABLE);    TIM_Cmd(TIM3, ENABLE);

 

 

三、main函数部分

通过修改CCRx寄存器，改变占空比。从而调整电流大小

while(1)    {            if(CCR3_Val >=0 && CCR3_Val <= 1000)            {                CCR3_Val -= 50;                Delay(1);            }            else            {                CCR3_Val = 1000;                Delay(1);            }            TIM3->CCR4 = CCR3_Val;            Delay(1);    }