超声波流量计stm32代码

超声波流量计是一种常用的流量测量设备，它通过发送超声波信号并测量信号的回波时间来计算流体的流速和流量。下面是一个基于STM32的超声波流量计的代码示例：

#include "stm32f10x.h"
#include "stdio.h"

#define TRIG_PIN GPIO_Pin_0
#define ECHO_PIN GPIO_Pin_1

void delay_us(uint32_t us)
{
    us *= 8;
    while (us--)
    {
        __NOP();
    }
}

void TIM2_Init(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

    TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
    TIM_TimeBaseStructure.TIM_Prescaler = 72 - 1;
    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

    TIM_Cmd(TIM2, ENABLE);
}

void GPIO_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

    GPIO_InitStructure.GPIO_Pin = TRIG_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = ECHO_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
}

float GetFlowRate(void)
{
    uint32_t start_time, end_time;
    float distance, flow_rate;

    GPIO_SetBits(GPIOA, TRIG_PIN);
    delay_us(10);
    GPIO_ResetBits(GPIOA, TRIG_PIN);

    while (GPIO_ReadInputDataBit(GPIOA, ECHO_PIN) == 0)
    {
        start_time = TIM_GetCounter(TIM2);
    }

    while (GPIO_ReadInputDataBit(GPIOA, ECHO_PIN) == 1)
    {
        end_time = TIM_GetCounter(TIM2);
    }

    distance = (end_time - start_time) * 0.0343 / 2;
    flow_rate = distance * 1000 / 60;

    return flow_rate;
}

int main(void)
{
    float flow_rate;

    TIM2_Init();
    GPIO_Init();

    while (1)
    {
        flow_rate = GetFlowRate();
        printf("Flow rate: %.2f L/min\r\n", flow_rate);

        // 延时一段时间后再次测量
        delay_us(1000000);
    }
}

这段代码使用了STM32的定时器和GPIO模块来实现超声波流量计的测量。其中，TRIG_PIN和ECHO_PIN分别连接到STM32的GPIO引脚，用于触发超声波信号和接收回波信号。通过计算回波时间和距离的关系，可以得到流速和流量。