USART3和TIM初始化的问题

王轩 · 发表于 2016-11-14 12:30:35

TIM8的初始化：

[mw_shl_code=c,true]void PWM_TIM8_Init(u16 arr,u16 psc)
{
GPIO_InitTypeDef GPIO_Init_TypeDef;
TIM_TimeBaseInitTypeDef TIM_TimeBaseInit_TypeDef;
TIM_OCInitTypeDef TIM_OCInit_TypeDef;
NVIC_InitTypeDef NVIC_Init_TypeDef;

RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM8 |
   RCC_APB2Periph_GPIOC, ENABLE);

TIM_DeInit(TIM8);

GPIO_Init_TypeDef.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init_TypeDef.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9;
GPIO_Init_TypeDef.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOC,&GPIO_Init_TypeDef);

TIM_TimeBaseInit_TypeDef.TIM_Period = arr;//设置在下一个更新事件装入活动的自动重装载寄存器周期的值
TIM_TimeBaseInit_TypeDef.TIM_Prescaler = (psc-1);//设置用来作为TIMx时钟频率除数的预分频值
TIM_TimeBaseInit_TypeDef.TIM_ClockDivision = TIM_CKD_DIV1;//设置时钟分割：TDTS = Tck_tim
TIM_TimeBaseInit_TypeDef.TIM_CounterMode = TIM_CounterMode_Up;//TIM向上计数模式
TIM_TimeBaseInit(TIM8,&TIM_TimeBaseInit_TypeDef);

TIM_OCInit_TypeDef.TIM_OCMode = TIM_OCMode_PWM2;//选择定时器模式 TIM脉冲宽度调制模式2
TIM_OCInit_TypeDef.TIM_OCPolarity = TIM_OutputState_Enable;//比较脉冲输出使能
TIM_OCInit_TypeDef.TIM_Pulse = 0;//设置待装入捕获比较寄存器的脉冲值
TIM_OCInit_TypeDef.TIM_OutputState = TIM_OCPolarity_High;//输出极性  TIM输出比较极性高
TIM_OC1Init(TIM8,&TIM_OCInit_TypeDef);//根据TIM_OCInitStruct中指定的参数初始化外设TIMx
TIM_OC2Init(TIM8,&TIM_OCInit_TypeDef);
TIM_OC3Init(TIM8,&TIM_OCInit_TypeDef);
TIM_OC4Init(TIM8,&TIM_OCInit_TypeDef);

TIM_CtrlPWMOutputs(TIM8,ENABLE); //MOE 主输出使能

TIM_OC1PreloadConfig(TIM8,TIM_OCPreload_Enable);//CH1预装载使能
TIM_OC2PreloadConfig(TIM8,TIM_OCPreload_Enable);//CH2预装载使能
TIM_OC3PreloadConfig(TIM8,TIM_OCPreload_Enable);//CH3预装载使能
TIM_OC4PreloadConfig(TIM8,TIM_OCPreload_Enable);//CH4预装载使能

NVIC_Init_TypeDef.NVIC_IRQChannel = TIM8_UP_IRQn;
NVIC_Init_TypeDef.NVIC_IRQChannelPreemptionPriority = 0;  //先占优先级0级
NVIC_Init_TypeDef.NVIC_IRQChannelSubPriority = 1;  //从优先级0级
NVIC_Init_TypeDef.NVIC_IRQChannelCmd = ENABLE; //IRQ通道被使能
NVIC_Init(&NVIC_Init_TypeDef);

TIM_ARRPreloadConfig(TIM8,ENABLE);//使能TIMx在ARR上的预装载寄存器
TIM_Cmd(TIM8, ENABLE);  //使能TIM8
}[/mw_shl_code]

USART3的初始化：
[mw_shl_code=c,true]void USART3_Init(u32 Baud)
{
GPIO_InitTypeDef GPIO_Init_TypeDef;
USART_InitTypeDef USART_Init_TypeDef;
NVIC_InitTypeDef NVIC_Init_TypeDef; //结构体重定义

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3,ENABLE);

//  USART3_TX GPIOB.10
GPIO_Init_TypeDef.GPIO_Mode = GPIO_Mode_AF_PP;//复用推挽输出
GPIO_Init_TypeDef.GPIO_Pin = GPIO_Pin_10;
GPIO_Init_TypeDef.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB,&GPIO_Init_TypeDef);

//  USART3_RX GPIOB.11
GPIO_Init_TypeDef.GPIO_Mode = GPIO_Mode_IN_FLOATING;//浮空输入
GPIO_Init_TypeDef.GPIO_Pin = GPIO_Pin_11;
GPIO_Init(GPIOB,&GPIO_Init_TypeDef);

// USART3 NVIC
NVIC_Init_TypeDef.NVIC_IRQChannel = USART3_IRQn;
NVIC_Init_TypeDef.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init_TypeDef.NVIC_IRQChannelPreemptionPriority = 3;//抢占优先级
NVIC_Init_TypeDef.NVIC_IRQChannelSubPriority = 2;//子优先级
NVIC_Init(&NVIC_Init_TypeDef);

// USART3 初始化设置
USART_Init_TypeDef.USART_BaudRate = Baud;//设置波特率
USART_Init_TypeDef.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//无硬件数据流控制
USART_Init_TypeDef.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
USART_Init_TypeDef.USART_Parity = USART_Parity_No;//无奇偶校验位
USART_Init_TypeDef.USART_StopBits = USART_StopBits_1;//一个停止位
USART_Init_TypeDef.USART_WordLength = USART_WordLength_8b;//字长为8位数据格式
USART_Init(USART3,&USART_Init_TypeDef);
USART_ITConfig(USART3,USART_IT_RXNE,ENABLE);
USART_Cmd(USART3,ENABLE);
}[/mw_shl_code]

现在遇到的问题就是：先初始化USART3 后初始化TIM8 TIM8产生PWM就会出问题，问题是只有CH4有波形 CH1-3无波形，
反过来，先初始化TIM8，再初始化USART3.TIM8就正常，不过偶尔会跑死。
他们两个有什么千丝万缕的关系