Tool/software: Code Composer Studio
Hello,
I am trying to configure my ultrasonic sensor to the MSP. After P1IES, the program loops inside the interrupt. I am not sure if it is a syntax issue or the set up of the interrupt. I found this sample code for the MSPG family, I converted some things on the syntax, but probably not all of it may be correct. Code is below
Thank You.
#include <msp430.h>
int miliseconds;
int distance;
long sensor;
void main(void)
{
//CSCTL1 = DCOFSEL_0; // submainclock 1mhz
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
TA1CCTL0 = CCIE; // CCR0 interrupt enabled
TA1CCR0 = 1000; // 1ms at 1mhz
TA1CTL = TASSEL_2 + MC_1; // SMCLK, upmode
//TA1CTL = TASSEL__ACLK | MC__CONTINUOUS;
P1IFG = 0x00; //clear all interrupt flags
P1DIR |= 0x01; // P1.0 as output for LED
P1OUT &= ~0x01; // turn LED off
__bis_SR_register(GIE);
//_BIS_SR(GIE); // global interrupt enable
while(1){
P1IE &= ~0x01; // disable interupt
P1DIR |= 0x02; // trigger pin as output
P1OUT |= 0x02; // generate pulse
__delay_cycles(10); // for 10us
P1OUT &= ~0x02; // stop pulse
P1DIR &= ~0x04; // make pin P1.2 input (ECHO)
P1IFG = 0x00; // clear flag just in case anything happened before
P1IE |= 0x04; // enable interupt on ECHO pin
P1IES &= ~0x04; // rising edge on ECHO pin
__delay_cycles(30000); // delay for 30ms (after this time echo times out if there is no object detected)
distance = sensor/58; // converting ECHO lenght into cm
if(distance < 20 && distance != 0) P1OUT |= 0x01; //turning LED on if distance is less than 20cm and if distance isn't 0.
else P1OUT &= ~0x01;
}
}
#pragma vector=PORT1_VECTOR
__interrupt void Port_1(void)
{
if(P1IFG&0x04) //is there interrupt pending?
{
if(!(P1IES&0x04)) // is this the rising edge?
{
TA1CTL|=TACLR; // clears timer A
miliseconds = 0;
P1IES |= 0x04; //falling edge
}
else
{
sensor = (long)miliseconds*1000 + (long)TA1R; //calculating ECHO length
}
P1IFG &= ~0x04; //clear flag
}
}
#pragma vector=TIMER0_A0_VECTOR
__interrupt void Timer_A (void)
{
miliseconds++;
}
