帮我找找这两之间有啥干涉。。。只要先初始化了串口，定时器初始化频率就设定不了，也就是主定时器溢出时间不收控制了

Y-Hanxiao · 发表于 2016-7-26 10:14:49

/*******************************
函数：PWM
说明：主定时器TIM4
   从定时器TIM1，产生PWM
参数：Frequency    频率
   Pulse_Width 脉宽
*******************************/
  void tim_pwm(u16 Frequency,u16 Pulse_Width)
{

   GPIO_InitTypeDef  GPIO_InitStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;
   TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
//    NVIC_InitTypeDef NVIC_InitStructure;

//时钟使能
   RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB, ENABLE); //引脚时钟使能
   RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);                      //TIM1时钟使能
   RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);                      //TIM4时钟使能

//主定时器初始化
TIM_TimeBaseStructure.TIM_Period = Frequency;                   //定时器加载值
TIM_TimeBaseStructure.TIM_Prescaler = 7199;                      //定时器分频值
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;          //设置时钟分割:TDTS = Tck_tim
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;       //TIM向上计数模式
TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);                   //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位

   //TIM_OC1PreloadConfig(TIM4, TIM_OCPreload_Enable);                //允许预装载
   TIM_SelectOutputTrigger(TIM4, TIM_TRGOSource_Update);             //选择主定时器的级联输出信号为TRGO。
   TIM_SelectMasterSlaveMode(TIM4, TIM_MasterSlaveMode_Enable);    //打开主定时器的主从模式

//从定时器引脚初始化
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_11;          //配置引脚PA8，PA11
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;                   //复用推挽输出
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;                //50MHZ速度
   GPIO_Init(GPIOA, &GPIO_InitStructure);

//从定时器初始化
TIM_TimeBaseStructure.TIM_Period = 10000;                         //定时器加载值    设置最大值为10ms
   TIM_TimeBaseStructure.TIM_Prescaler = 71;                         //定时器分频值    设置精度为1us.
TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);                   //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位

   TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;                //PWM2模式
   TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;    //比较输出使能
   TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;       //高电平有效
   TIM_OCInitStructure.TIM_Pulse = 10001-Pulse_Width;                //脉宽
   TIM_OC1Init(TIM1, &TIM_OCInitStructure);                         //从定时器的CH1输出

   TIM_OCInitStructure.TIM_Pulse = 10001-20;                         //脉宽
   TIM_OC4Init(TIM1, &TIM_OCInitStructure);                         //从定时器的CH1输出

TIM_SelectOnePulseMode(TIM1,TIM_OPMode_Single);                   //单脉冲模式

// TIM_OC1PreloadConfig(TIM1,TIM_OCPreload_Enable);                //允许预装载
// TIM_OC4PreloadConfig(TIM1,TIM_OCPreload_Enable);                //允许预装载

   TIM_SelectSlaveMode(TIM1,TIM_SlaveMode_Trigger);                //从定时器的从模式选择,触发模式
   TIM_SelectMasterSlaveMode(TIM1,TIM_MasterSlaveMode_Enable);       //打开主定时器的主从模式
   TIM_SelectInputTrigger(TIM1,TIM_TS_ITR3);                         //选择从定时器为外部时钟触发.

TIM_CtrlPWMOutputs(TIM1,ENABLE);                                     //MOE 主输出使能

//TIM_Cmd(TIM4, ENABLE);                                        //从定时器使能

}

//串口
void uart2_init(u32 bound)
{
//GPIO端口设置
GPIO_InitTypeDef GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);                            //使能USART1，GPIOA时钟
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);                         //使能USART1，GPIOA时钟
// USART_DeInit(USART2);                                                       //复位串口1

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;                                     //PA.2 USART1_TX
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;                                  //复用推挽输出
GPIO_Init(GPIOA, &GPIO_InitStructure);                                        //初始化PA9

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;                                     //PA.3 USART1_RX
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;                         //浮空输入
GPIO_Init(GPIOA, &GPIO_InitStructure);                                        //初始化PA10

//Usart2NVIC 配置
NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;                            // USART2_IRQn通道
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3 ;                      //抢占优先级3
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;                            //子优先级3
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;                            //IRQ通道使能
NVIC_Init(&NVIC_InitStructure);                                                 //根据指定的参数初始化VIC寄存器

//USART 初始化设置
USART_InitStructure.USART_BaudRate = bound;                                  //一般设置为9600;
USART_InitStructure.USART_WordLength = USART_WordLength_8b;                   //字长为8位数据格式
USART_InitStructure.USART_StopBits = USART_StopBits_1;                         //一个停止位
USART_InitStructure.USART_Parity = USART_Parity_No;                            //无奇偶校验位
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None; //无硬件数据流控制
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;                //收发模式
USART_Init(USART2, &USART_InitStructure);                                     //初始化串口
USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);                               //开启中断
USART_Cmd(USART2, ENABLE);                                                    //使能串口
}