我想把stm32 f407 pwm的例子，改成PA8端口输出pwm。编译没错误，但是没波形。哪位大神帮我看看

麦迪 · 发表于 2015-4-16 16:16:34

[mw_shl_code=c,true]int main(void) { NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);//设置系统中断优先级分组2 delay_init(168); //初始化延时函数 uart_init(115200);//初始化串口波特率为115200 TIM1_PWM_Init(500-1,84-1); //84M/84=1Mhz的计数频率,重装载值500，所以PWM频率为 1M/500=2Khz. while(1) //实现比较值从0-300递增，到300后从300-0递减，循环 { delay_ms(10); TIM_SetCompare1(TIM1,250); //修改比较值，修改占空比 } }[/mw_shl_code]

[mw_shl_code=c,true]void TIM1_PWM_Init(u32 arr,u32 psc) { //此部分需手动修改IO口设置 GPIO_InitTypeDef GPIO_InitStructure; TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; TIM_OCInitTypeDef TIM_OCInitStructure; //RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM14,ENABLE); //TIM14时钟使能 RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1,ENABLE); // RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOF, ENABLE); //使能PORTF时钟 RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE); //GPIO_PinAFConfig(GPIOF,GPIO_PinSource9,GPIO_AF_TIM14); //GPIOF9复用为定时器14 GPIO_PinAFConfig(GPIOA,GPIO_PinSource8,GPIO_AF_TIM1 ); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8; //GPIOF9 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; //复用功能 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz; //速度100MHz GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //推挽复用输出 GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; //上拉 GPIO_Init(GPIOA,&GPIO_InitStructure); //初始化PF9 TIM_TimeBaseStructure.TIM_Prescaler=psc; //定时器分频 TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; //向上计数模式 TIM_TimeBaseStructure.TIM_Period=arr; //自动重装载值 TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1; TIM_TimeBaseInit(TIM1,&TIM_TimeBaseStructure);//初始化定时器14 //初始化TIM14 Channel1 PWM模式 TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //选择定时器模式:TIM脉冲宽度调制模式2 TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比较输出使能 TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; //输出极性:TIM输出比较极性低 TIM_OC1Init(TIM1, &TIM_OCInitStructure); //根据T指定的参数初始化外设TIM1 4OC1 TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Enable); //使能TIM14在CCR1上的预装载寄存器[/mw_shl_code] [mw_shl_code=c,true][/mw_shl_code] [mw_shl_code=c,true] TIM_CtrlPWMOutputs(TIM1,ENABLE); //MOV置一 TIM_ARRPreloadConfig(TIM1,ENABLE);//ARPE使能 TIM_Cmd(TIM1, ENABLE); //使能TIM14 } [/mw_shl_code]