Hey Thanks for the reply, so I pushed the timerIsr up to 5ms and then had it print me a message and you were right, it printed the message once and then halfway through a second time before stopping. Then I pushed the baud rate to 250k and it printed the message a bunch of times an then printed the distance in between. How ever the distance was still repeating, so does that mean with the 250k baud rate it still isn't clearing the time status register? I put the serial print in the void(timerIsr).
#include<DueTimer.h> // Header file for DueTimer file library
const byte trigPin = 12; // Pin 12 trigger output
const byte echoPin = 8; // Pin 8 Echo input
const unsigned long TICK_COUNTS = 4000; // count down timer
volatile long echo_start = 0; // Records start of echo pulse
volatile long echo_end = 0; // Records end of echo pulse
volatile long echo_duration = 0; // Duration - difference between end and start
volatile int trigger_time_count = 0; // Count down counter to trigger pulse time
unsigned long previousMillis=0; // millis() returns an unsigned long.
unsigned long previousMillisB =0;
static volatile unsigned int stateB = 1;
void setup() {
// put your setup code here, to run once:
pinMode(13,OUTPUT);
pinMode(trigPin, OUTPUT); // Trigger pin set to output
pinMode(echoPin, INPUT); // Echo pin set to input
// Timer2.attachInterrupt(
Timer3.attachInterrupt(timerIsr).setPeriod(5000).start(); // timer interrupt to control trigger pulse, 50uS timer.
attachInterrupt(8, echo_interrupt, CHANGE); // Attach interrupt to the sensor echo input
Serial.begin (250000);
digitalWrite(13,LOW);
}
void loop(){
unsigned long currentMillisB = millis();
unsigned long currentMillis = millis();
static volatile long distance, distanceA;
distance = (echo_duration/58); // distance computed from the echo pulse
if(currentMillis-previousMillis >= 100){ // every 500 millis run print code
distanceA = distance; // Set distanceA to whatever distance has been computed
Serial.print("A");
Serial.println(distanceA); // print ditanceA
previousMillis = millis();
}
/*if((currentMillisB-previousMillisB)>= 20){
stateB = 1;
//Serial.print("CB");
//Serial.println(currentMillisB);
previousMillisB = millis();
}*/
}
void timerIsr()
{
trigger_pulse(); // Schedule the trigger pulses sensor 1
Serial.println("So triggered bro.. ;-)"); // debug serial print line, remove later. :-)
}
void trigger_pulse()
{
//static volatile int stateB = 1; // State machine variable
if (!(--trigger_time_count)) // Count to 200mS
{ // Time out - Initiate trigger pulse
trigger_time_count = TICK_COUNTS; // Reload
stateB = 1; // Changing to state 1 initiates a pulse
}
switch(stateB) // State machine handles delivery of trigger pulse
{
case 0: // Normal state does nothing
break;
case 1: // Initiate pulse
digitalWrite(trigPin, HIGH); // Set the trigger output high
stateB = 2; // and set state to 2
break;
case 2: // Complete the pulse
default:
digitalWrite(trigPin, LOW); // Set the trigger output low
stateB = 0; // and return state to normal 0
break;
}
}
void echo_interrupt()
{
switch (digitalRead(echoPin)) // Test to see if the signal is high or low
{
case HIGH: // High so must be the start of the echo pulse
echo_end = 0; // Clear the end time
echo_start = micros(); // Save the start time
break;
case LOW: // Low so must be the end of hte echo pulse
echo_end = micros(); // Save the end time
echo_duration = echo_end - echo_start; // Calculate the pulse duration
break;
}
}