写一个STM32使用TIM3通道1的HC-SR04测距函数

好的，以下是使用STM32使用TIM3通道1的HC-SR04测距函数的代码：

#include "stm32f10x.h"

#define TRIG_PIN GPIO_Pin_0
#define TRIG_PORT GPIOA
#define ECHO_PIN GPIO_Pin_6
#define ECHO_PORT GPIOB

void delay_us(uint32_t us)
{
    uint32_t ticks;
    ticks = us * (SystemCoreClock / 1000000);
    while(ticks--);
}

float hc_sr04_measure_distance(void)
{
    GPIO_ResetBits(TRIG_PORT, TRIG_PIN);
    delay_us(2);
    GPIO_SetBits(TRIG_PORT, TRIG_PIN);
    delay_us(10);
    GPIO_ResetBits(TRIG_PORT, TRIG_PIN);

    while(!GPIO_ReadInputDataBit(ECHO_PORT, ECHO_PIN));
    uint32_t start = SysTick->VAL;
    while(GPIO_ReadInputDataBit(ECHO_PORT, ECHO_PIN));
    uint32_t end = SysTick->VAL;

    float distance = (start - end) * 0.034 / 2;
    return distance;
}

int main(void)
{
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB, ENABLE);

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

    GPIO_InitStructure.GPIO_Pin = ECHO_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(ECHO_PORT, &GPIO_InitStructure);

    while(1)
    {
        float distance = hc_sr04_measure_distance();
        // do something with distance
    }
}

希望这个函数对你有所帮助！