oid TIM3_Init(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
/* PWM信号电平跳变值 */
// u16 CCR1= 36000;
// u16 CCR2= 36000;
/*PCLK1经过2倍频后作为TIM3的时钟源等于72MHz*/
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
/* Time base configuration */
TIM_TimeBaseStructure.TIM_Period =1599; //计数周期1600
TIM_TimeBaseStructure.TIM_Prescaler = 1; //设置预分频：预分频=2，即为72/3=24MHz
TIM_TimeBaseStructure.TIM_ClockDivision = 0; //设置时钟分频系数：不分频
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //向上计数溢出模式
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
/* PWM1 Mode configuration: Channel1 */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //配置为PWM模式1
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse =600; //设置跳变值，当计数器计数到这个值时，电平发生跳变
TIM_OCInitStructure.TIM_OCPolarity =TIM_OCPolarity_Low; //当定时器计数值小于CCR1时为高电平
TIM_OC1Init(TIM3, &TIM_OCInitStructure); //使能通道1
TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);
/* PWM1 Mode configuration: Channel2 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = 300; //设置通道2的电平跳变值，输出另外一个占空比的PWM
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //当定时器计数值小于CCR2时为低电平
TIM_OC2Init(TIM3, &TIM_OCInitStructure); //使能通道2
TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);
TIM_ARRPreloadConfig(TIM3, ENABLE); //使能TIM3重载寄存器ARR
/* TIM3 enable counter */
TIM_Cmd(TIM3, ENABLE);
Delay_8ms();
TIM_Cmd(TIM3, DISABLE);
}