stm32超声波模块测距

ID:283304 · 发表于 2018-10-9 17:40

/******************** *******************************************************
* 文件名  : UltrasonicWave.c
* 描述：超声波测距模块，
初始化 Ultrasonic_Init()
         UltrasonicWave_StartMeasure 发送超声波启动
返回中断Echo中得到高电平时间，从而获取距离
exti ISR 中调ultrasonic_calculate（）；
注意本模块使用到timer2
*********************************************************************************/

struct UltrasonicDefine U_GPIO_Define;
volatile uint16_t ultrasonic_wave_measure_data;
/*************************************************************
  Function ：Ultrasonic_Config
  Description：超声波的引脚配置
  Input    : UltrasonicDefine类型源参数
  return    : none
*************************************************************/
void ultrasonic_configuratioin(struct UltrasonicDefine defines)
{
struct UltrasonicDefine def = defines;
GPIO_InitTypeDef GPIO_InitStructure;
EXTI_InitTypeDef EXTI_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;

U_GPIO_Define = defines;

  GPIO_InitStructure.GPIO_Pin = def.pin_of_trig;
  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_OUT;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_DOWN;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz;
  GPIO_Init(def.pin_of_trig_group, &GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin  = def.pin_of_echo;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_DOWN;
  GPIO_Init(def.pin_of_echo_group, &GPIO_InitStructure);

  SYSCFG_EXTILineConfig(def.gpio_portsource, def.gpio_pinsource);

EXTI_InitStructure.EXTI_Line = def.exit_line_no;
  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;
  EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  EXTI_Init(&EXTI_InitStructure);

NVIC_InitStructure.NVIC_IRQChannel                = def.irqn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority       = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd             = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}

/*************************************************************
  Function ：Timer2_Init
  Description：通用定时器中断初始化这里使用的是TIM2 系统时钟system_sclk是16MHZ
  Input    : arr：自动重装值。 psc：时钟预分频数
  return    : none
*************************************************************/
static void timer2_init(uint16_t arr,uint16_t psc)
{
  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

TIM_TimeBaseStructure.TIM_Period =  arr; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值    计数到5000为500ms
TIM_TimeBaseStructure.TIM_Prescaler =    (psc-1); //设置用来作为TIMx时钟频率除数的预分频值  10Khz的计数频率
TIM_TimeBaseStructure.TIM_ClockDivision =  TIM_CKD_DIV1; //设置时钟分割:TDTS = Tck_tim
TIM_TimeBaseStructure.TIM_CounterMode =  TIM_CounterMode_Up;  //TIM向上计数模式
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
}
/*************************************************************
  Function ：Ultrasonic_Init
  Description：初始化 Ultrasonic Module Pins以及记录高电平（返回信号）时间的timer 初始化
  Input    : none
  return    : none
*************************************************************/
void ultrasonic_init(void)
{
timer2_init(5000, 3200);    //500ms  for sysclk = 32MHz
}

/*************************************************************
  Function ：UltrasonicWave_StartMeasure
  Description：发送一个大于10us的高电平
|--------|
------|       |------  > 10us
  Input    : none
  return    : none
*************************************************************/
void ultrasonicWave_startMeasure(void)
{
  GPIO_SetBits(U_GPIO_Define.pin_of_trig_group,U_GPIO_Define.pin_of_trig);    //送>10US的高电平
  Delay_nus(15);                         //延时15US
  GPIO_ResetBits(U_GPIO_Define.pin_of_trig_group,U_GPIO_Define.pin_of_trig);
}
/*************************************************************
  Function ：Ultrasonic_GetData
  Description：统计返回echo的高电平时间，得到距离的精度是17mm
  Input    : none
  return    : 得到的距离，单位是mm
*************************************************************/
uint16_t ultrasonic_calculate(void)
{
uint16_t UltrasonicWave_Distance;

TIM_SetCounter( TIM2, 0 );
TIM_Cmd( TIM2, ENABLE );
while(GPIO_ReadInputDataBit( U_GPIO_Define.pin_of_echo_group,
U_GPIO_Define.pin_of_echo ) );
TIM_Cmd( TIM2, DISABLE );
UltrasonicWave_Distance = TIM_GetCounter(TIM2)*17;
return UltrasonicWave_Distance;
}

uint16_t ultrasonic_wave_get_result(void)
{
return ultrasonic_wave_measure_data;
}

void clear_last_measure_result(void)
{
ultrasonic_wave_measure_data = 0;
}

void ultrasonic_wave_test(void)
{
uint16_t distance_ultrasonic;

distance_ultrasonic = ultrasonic_wave_get_result();
{
printf("get ultrasonic wave distance : %d \n", distance_ultrasonic);
OLED_ShowString(10, 0, "Ultra"  );
OLED_ShowString(0 , 2, "Distance:(mm)" );
OLED_ShowNum (50, 4, distance_ultrasonic , 3, 16);
clear_last_measure_result();
}
ultrasonicWave_startMeasure();
}

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