STM32测相位差（根据时间差）
两路方波输入到stm32的两路定时器通道，通过检测高电平到来的时间差从而算出相位差，
公式 相位差=360*频率*（时间差）
如果要测正弦波，可以通过电压比较电路转为方波
定时器初始化及定时器中断代码：
void TIM5_Cap_Init(uint16_t arr,uint16_t psc)
{RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);GPIO_InitTypeDef GPIO_InitStructure;GPIO_InitStructure.GPIO_Mode=GPIO_Mode_IPD;GPIO_InitStructure.GPIO_Pin=GPIO_Pin_3|GPIO_Pin_2;GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;GPIO_Init(GPIOA,&GPIO_InitStructure);RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM5,ENABLE);TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;TIM_TimeBaseStructInit(&TIM_TimeBaseInitStructure);TIM_TimeBaseInitStructure.TIM_ClockDivision=TIM_CKD_DIV1;TIM_TimeBaseInitStructure.TIM_CounterMode=TIM_CounterMode_Up;TIM_TimeBaseInitStructure.TIM_Period=arr;TIM_TimeBaseInitStructure.TIM_Prescaler=psc;TIM_TimeBaseInit(TIM5,&TIM_TimeBaseInitStructure);TIM_ICInitTypeDef TIM_ICInitStructure;TIM_ICInitStructure.TIM_Channel=TIM_Channel_4;TIM_ICInitStructure.TIM_ICFilter=0x00;TIM_ICInitStructure.TIM_ICPolarity=TIM_ICPolarity_Rising;TIM_ICInitStructure.TIM_ICPrescaler=TIM_ICPSC_DIV1;TIM_ICInitStructure.TIM_ICSelection=TIM_ICSelection_DirectTI;TIM_ICInit(TIM5,&TIM_ICInitStructure);TIM_ICInitStructure.TIM_Channel=TIM_Channel_3;TIM_ICInitStructure.TIM_ICFilter=0x00;TIM_ICInitStructure.TIM_ICPolarity=TIM_ICPolarity_Rising;TIM_ICInitStructure.TIM_ICPrescaler=TIM_ICPSC_DIV1;TIM_ICInitStructure.TIM_ICSelection=TIM_ICSelection_DirectTI;TIM_ICInit(TIM5,&TIM_ICInitStructure);NVIC_InitTypeDef NVIC_InitStructure;NVIC_InitStructure.NVIC_IRQChannel=TIM5_IRQn;NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=2;NVIC_InitStructure.NVIC_IRQChannelSubPriority=1;NVIC_Init(&NVIC_InitStructure);TIM_ITConfig(TIM5,TIM_IT_Update|TIM_IT_CC4|TIM_IT_CC3,ENABLE);TIM_Cmd(TIM5,ENABLE);
}u8 TIM5CH4_Cap_State; //第一路信号捕获标志
u16 TIM5CH4_Cap_Value; //第一路信号捕获值
u8 TIM5CH3_Cap_State; //第二路信号捕获标志
u16 TIM5CH3_Cap_Value; //第二路信号捕获值void TIM5_IRQHandler()
{if((TIM5CH4_Cap_State&0x80)==0) //第一路信号未捕获到下降沿{if(TIM_GetITStatus(TIM5,TIM_IT_Update)==SET){if(TIM5CH4_Cap_State&0x40) //第一路信号已捕获到上升沿{if((TIM5CH4_Cap_State&0x3f)==0x3f) //第一路信号上升沿到下降沿时间过长，捕获失败{TIM5CH4_Cap_State|=0x80; TIM5CH4_Cap_Value=0xffff;}else TIM5CH4_Cap_State++;}}if(TIM_GetITStatus(TIM5,TIM_IT_CC4)==SET) //捕获中断{if(TIM5CH4_Cap_State&0x40) //第一路信号已经捕获到上升沿，则此次为下降沿被捕获{TIM5CH4_Cap_State|=0x80; //标志一次检测完成TIM5CH4_Cap_Value=TIM_GetCapture4(TIM5); //取出定时器的值TIM_OC4PolarityConfig(TIM5,TIM_ICPolarity_Rising); //设置为上升沿捕获}else //第一路未捕获到上升沿，则此次为上升沿被捕获{TIM5CH4_Cap_State=0;TIM5CH4_Cap_Value=0;TIM_SetCounter(TIM5,0);TIM5CH4_Cap_State|=0X40; //标记捕获到上升沿TIM_OC4PolarityConfig(TIM5,TIM_ICPolarity_Falling); //设置为下降沿捕获}}}if((TIM5CH3_Cap_State&0x80)==0) {if(TIM_GetITStatus(TIM5,TIM_IT_Update)==SET){if(TIM5CH3_Cap_State&0x40) {if((TIM5CH3_Cap_State&0x3f)==0x3f) {TIM5CH3_Cap_State|=0x80; TIM5CH3_Cap_Value=0xffff;}else TIM5CH3_Cap_State++;}}if(TIM_GetITStatus(TIM5,TIM_IT_CC3)==SET) {if(TIM5CH3_Cap_State&0x40) {TIM5CH3_Cap_State|=0x80; TIM5CH3_Cap_Value=TIM_GetCapture3(TIM5); TIM_OC3PolarityConfig(TIM5,TIM_ICPolarity_Rising); }else {TIM5CH3_Cap_State=0;TIM5CH3_Cap_Value=0;TIM_SetCounter(TIM5,0);TIM5CH3_Cap_State|=0X40; TIM_OC3PolarityConfig(TIM5,TIM_ICPolarity_Falling); }}}TIM_ClearITPendingBit(TIM5,TIM_IT_Update|TIM_IT_CC4|TIM_IT_CC3);
}
在主程序中求其中一路信号的频率，再使用开头给出的公式可求得相位差
下面给出关于求相位差部分的主程序代码：
if((TIM5CH4_Cap_State&0x80) && (TIM5CH3_Cap_State&0x80)){timer4_temp=TIM5CH4_Cap_State&0x3f;timer4_temp*=65536;timer4_temp+=TIM5CH4_Cap_Value;timer3_temp=TIM5CH3_Cap_State&0x3f;timer3_temp*=65536;timer3_temp+=TIM5CH3_Cap_Value;if(timer4_temp > timer3_temp)time_diff = timer4_temp - timer3_temp;elsetime_diff = timer3_temp - timer4_temp;phase_diff = 360*F*time_diff/1000000;LCD_ShowNum(410,5+24*1,phase_diff,4,24);LCD_ShowString(410+4*12,5+24*1,12,24,24,".");LCD_ShowNum(410+5*12,5+24*1,(u16)(phase_diff*10)%10,1,24);TIM5CH4_Cap_State = 0;TIM5CH3_Cap_State = 0;}
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