/定时器1的配置 输出两路PWM信号 PA8 PA11,计数时钟为400KHZ 计数溢出大小为40000 /

void Tim1Init(void)

{ 

 GPIO_InitTypeDef GPIO_InitStruct;

 TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;

 TIM_OCInitTypeDef TIM_OCInitStruct;

 u16 LeftMotor_CCR;  

 u16 RightMotor_CCR;

 RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1|RCC_APB2Periph_GPIOA|RCC_APB2Periph_AFIO, ENABLE);  

 GPIO_InitStruct.GPIO_Pin   = GPIO_Pin_8 | GPIO_Pin_11 ; // 定时器1 通道1和4 

 GPIO_InitStruct.GPIO_Mode  = GPIO_Mode_AF_PP;

 GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;

 GPIO_Init(GPIOA, &GPIO_InitStruct);

 LeftMotor_CCR = RightMotor_CCR = 2000;

 //在APB2设置为72MHZ的基础上，对定时器1进行配置 

 TIM_TimeBaseInitStruct.TIM_RepetitionCounter = 0;            // 重复计数器无效 */      

 TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up; // 向上计数 */

 TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;     // 时钟分频 */

 TIM_TimeBaseInitStruct.TIM_Prescaler = 180-1;                // 预分频系数为180-1，计数器时钟为72MHz/180 = 400KHz */              

 TIM_TimeBaseInitStruct.TIM_Period = 40000-1;               

 TIM_TimeBaseInit(TIM1, &TIM_TimeBaseInitStruct);

 TIM_OCInitStruct.TIM_OutputNState = TIM_OutputNState_Disable;

 TIM_OCInitStruct.TIM_OCMode = TIM_OCMode_PWM2;

 TIM_OCInitStruct.TIM_OutputState  = TIM_OutputState_Enable;

 TIM_OCInitStruct.TIM_OCPolarity   = TIM_OCPolarity_Low;

 TIM_OCInitStruct.TIM_Pulse = LeftMotor_CCR;  

 TIM_OC1Init(TIM1, &TIM_OCInitStruct);

 TIM_OCInitStruct.TIM_Pulse = RightMotor_CCR;

 TIM_OC4Init(TIM1, &TIM_OCInitStruct);

 TIM_Cmd(TIM1, ENABLE);

 TIM_CtrlPWMOutputs(TIM1, ENABLE);

}