Hi Team,
volatile uint32_t time = 0;
volatile uint32_t Distance = 0;
void HC_SR04_Init(void)
{
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
//enable GPIO_B
GPIOPinTypeGPIOInput(GPIO_PORTB_BASE, GPIO_PIN_4);
GPIOPinTypeGPIOOutput(GPIO_PORTB_BASE, GPIO_PIN_5);
GPIOPinWrite(GPIO_PORTB_BASE ,GPIO_PIN_5 ,0);
}
void Timer0A_Handler(void) {
static uint32_t time_count=0;
//Read Timer Interrupt Status
uint32_t status=TimerIntStatus( TIMER0_BASE, true);
//Clear interrupt flag bit
TimerIntClear( TIMER0_BASE, status);
time ++;
}
uint32_t sonar_mm(void )
{
GPIOPinWrite(GPIO_PORTB_BASE, GPIO_PIN_5, GPIO_PIN_5);//Trig high
delay_us(18);
GPIOPinWrite(GPIO_PORTB_BASE, GPIO_PIN_5, 0);
while(GPIOPinRead(GPIO_PORTB_BASE ,GPIO_PIN_4) == 0); //Wait for low end
time=0;
while(GPIOPinRead(GPIO_PORTB_BASE ,GPIO_PIN_4) == 1)
{
;
}
Distance=(time*346)/2; //Calculate the distance, and sound velocity in 25°C air is 346 m/s.
return Distance ;
}
void Timer_Init(void) {
//enable TIMER0，16/32bit
SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER0);
//Configure the timer, split the timer, and configure Timer a after the timer to be periodic
TimerConfigure( TIMER0_BASE, TIMER_CFG_SPLIT_PAIR|TIMER_CFG_A_PERIODIC_UP);
TimerLoadSet( TIMER0_BASE, TIMER_A,
SysCtlClockGet()/100000-1);//1us
//Register the interrupt function for Timer A.
TimerIntRegister( TIMER0_BASE, TIMER_A,
Timer0A_Handler);
TimerIntEnable( TIMER0_BASE, TIMER_TIMA_TIMEOUT);
//Set interrupt priority
IntPrioritySet( INT_TIMER0A, 0);
//Enable interrupts
IntEnable( INT_TIMER0A);
IntMasterEnable();
//Enable the timer
TimerEnable( TIMER0_BASE, TIMER_A);
}
int main(void)
{
HardWave_Init();//Serial interface, system clock initialization
HC_SR04_Init();
Timer_Init();
printf("Initialization complete \n");
while(1)//The main loop
{
printf("%d\n",sonar_mm() );
delay_ms(10);
}
}
The ultrasonic readout using the above method always returns 0. Could you help check is there anything need to be modified? Thanks.
Best Regards,
Cherry
