STM32F407测两路高速(最高200K)脉冲频率

hangeV · 发表于 2021-7-13 17:20:49

使用的定时器3和定时器4的ETR引脚，定时器6开250ms中断，中断里读定时器3和4的计数值并清零，乘以4得到频率。
问题：不准，500HZ得到的有580、560等等，示波器开着波形很好是500HZ。

static void mTIM3_ETR_cfg(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE); //PORTD 时钟使能
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //TIM3 时钟使能
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2; //GPIOD2
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; //复用功能
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz; //速度 100MHz
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; //外部已有100K上拉
GPIO_Init(GPIOD, &GPIO_InitStructure); //初始化 PD2
GPIO_PinAFConfig(GPIOD, GPIO_PinSource2, GPIO_AF_TIM3); //PD2 复用为定时器3
TIM_TimeBaseStructure.TIM_Period = 0xFFFF; //自动重装载值
TIM_TimeBaseStructure.TIM_Prescaler = 0x00; //定时器分频
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; //时钟分频
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //向上计数模式
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
TIM_ETRClockMode2Config(TIM3, TIM_ExtTRGPSC_OFF, TIM_ExtTRGPolarity_Inverted, 0);
TIM_SetCounter(TIM3, 0);
TIM_Cmd(TIM3, ENABLE); //使能定时器
}
static void mTIM4_ETR_cfg(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE, ENABLE); //PORTE 时钟使能
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE); //TIM4 时钟使能
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0; //GPIOE0
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; //复用功能
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz; //速度 100MHz
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; //外部已有100K上拉
GPIO_Init(GPIOE, &GPIO_InitStructure); //初始化 PE0
GPIO_PinAFConfig(GPIOE, GPIO_PinSource0, GPIO_AF_TIM4); //PE0 复用为定时器4
TIM_TimeBaseStructure.TIM_Period = 0xFFFF; //自动重装载值
TIM_TimeBaseStructure.TIM_Prescaler = 0x00; //定时器分频
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; //时钟分频
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //向上计数模式
TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);
TIM_ETRClockMode2Config(TIM4, TIM_ExtTRGPSC_OFF, TIM_ExtTRGPolarity_Inverted, 0);
TIM_SetCounter(TIM4, 0);
TIM_Cmd(TIM4, ENABLE); //使能定时器
}
void mTIM6_Config(u16 TIM_period, u16 TIM_prescaler, u8 TIM_clockDivision)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM6, ENABLE);
TIM_TimeBaseInitStructure.TIM_Period = TIM_period; //自动重装载值
TIM_TimeBaseInitStructure.TIM_Prescaler = TIM_prescaler; //定时器分频
TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_clockDivision;
TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up; //向上计数模式
TIM_TimeBaseInit(TIM6, &TIM_TimeBaseInitStructure);
TIM_ClearITPendingBit(TIM6, TIM_IT_Update);
TIM_Cmd(TIM6, ENABLE); //使能TIMx外设
TIM_ITConfig(TIM6, TIM_IT_Update, ENABLE); //使能指定的TIM中断
}
static u32 pulse1_250ms_Cnt = 0, pulse2_250ms_Cnt = 0;
void TIM6_DAC_IRQHandler(void) //定时器6中断函数，不能重命名
{
if(TIM_GetITStatus(TIM6, TIM_IT_Update) != RESET)
{
TIM_ClearITPendingBit(TIM6, TIM_IT_Update); //清中断标志
pulse1_250ms_Cnt = TIM3->CNT;
pulse2_250ms_Cnt = TIM4->CNT;
TIM3->CNT = 0;
TIM4->CNT = 0;
}
}
void mDIN_pulseMeasInit(void)
{
mTIM3_ETR_cfg();
mTIM4_ETR_cfg();
mTIM6_Config(2500 - 1, 8400 - 1, 0); //250ms中断一次(1000/250*65535>200000)
}
void mDIN_pulseGetFre(u32 fre[2])
{
fre[0] = pulse1_250ms_Cnt * 4; //转为hz
fre[1] = pulse2_250ms_Cnt * 4;
}