接下来就是解调。笔者用了两次解调才把基带信号完整复现出来。先来看看初步解调代码,用的是TIM1的输入捕获模块,TIM1属于高级定时器,和通用定时器的代码还是有些地方不一样的,比如输入捕获中断函数名为TIM1_CC_IRQHandler()。
void TIM1_Cap_Init(u16 arr,u16 psc)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_ICInitTypeDef TIM1_ICInitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;
GPIO_Init(GPIOA, &GPIO_InitStructure);
GPIO_ResetBits(GPIOA,GPIO_Pin_8);
TIM_TimeBaseStructure.TIM_Period = arr;
TIM_TimeBaseStructure.TIM_Prescaler =psc;
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);
TIM1_ICInitStructure.TIM_Channel = TIM_Channel_1; //CC1S=01
TIM1_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
TIM1_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
TIM1_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
TIM1_ICInitStructure.TIM_ICFilter = 0x00;
TIM_ICInit(TIM1, &TIM1_ICInitStructure);
NVIC_InitStructure.NVIC_IRQChannel = TIM1_CC_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
TIM_ITConfig(TIM1,TIM_IT_CC1,ENABLE);
TIM_Cmd(TIM1,ENABLE );
}
评论
查看更多