STM 32超音波測距モジュールHCSR-04ドライバ
超音波測距原理見:超音波測距原理超音波測距モジュール:HC-SR 04タイマー及び外部割り込み方式を採用
/*******************************************************************************
Driver for HC-SR04
:STM32F103ZET6
:TRIG--PC0 ECHO--PC1
*******************************************************************************/
#include "sonar_hcsr04.h"
#include "systime.h"
#define SONAR_PORT GPIOC
#define TRIG_PIN GPIO_Pin_0
#define ECHO_PIN GPIO_Pin_1
static volatile uint32_t measurement;
void hcsr04Init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
EXTI_InitTypeDef EXTI_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC , ENABLE);
GPIO_InitStructure.GPIO_Pin = TRIG_PIN;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_Init(SONAR_PORT, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = ECHO_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(SONAR_PORT, &GPIO_InitStructure);
GPIO_ResetBits(SONAR_PORT, ECHO_PIN);
GPIO_EXTILineConfig(GPIO_PortSourceGPIOC, GPIO_PinSource1); //
EXTI_ClearITPendingBit(EXTI_Line1);
EXTI_InitStructure.EXTI_Line = EXTI_Line1;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising_Falling;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure);
/* Enable TIM5 clock */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM5, ENABLE);
/* TIME5 base configuration */
TIM_TimeBaseInitStructure.TIM_Period = 0xFFFF; // 65536
TIM_TimeBaseInitStructure.TIM_Prescaler = 72-1; // ,F=72MHz/72=1MHz,T=1us
TIM_TimeBaseInitStructure.TIM_ClockDivision = 0; // ,
TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up; //
TIM_TimeBaseInit(TIM5, &TIM_TimeBaseInitStructure); // TIME5
TIM_Cmd(TIM5, DISABLE);
}
/**
*
*/
void hcsr04StartRanging(void)
{
GPIO_SetBits(SONAR_PORT, TRIG_PIN);
delay_us(20); // The width of trig signal must be greater than 10us
GPIO_ResetBits(SONAR_PORT, TRIG_PIN);
}
/**
*
* @return distance units:cm
*/
float hcsr04GetDistance(void)
{
// distance = measurement/2/1000000*340*100 = measurement/59 (cm) measurement-units:us
float distance = measurement / 58.8; // measurement-units:us
return distance;
}
static void ECHO_EXTI_IRQHandler(void)
{
if (EXTI_GetITStatus(EXTI_Line1) != RESET) {
if (GPIO_ReadInputDataBit(SONAR_PORT, ECHO_PIN) != 0) { //
TIM_Cmd(TIM5, ENABLE);
} else {
TIM_Cmd(TIM5, DISABLE);
measurement = TIM_GetCounter(TIM5);
TIM_SetCounter(TIM5, 0);
}
}
EXTI_ClearITPendingBit(EXTI_Line1);
}
void EXTI1_IRQHandler(void)
{
ECHO_EXTI_IRQHandler();
}