"undefined reference" when compiling sketches that use pulseIn() for Portenta H7 boards

[per1234]

pulseIn() has not yet been implemented for the Portenta.

undefined reference to `pulseIn'

[hpssjellis]

@per1234 can we have an update on this? I am trying to get an UltraSonic Rangefinder working and it uses pulseIn(). I feel that this function could be done from scratch. If it is not yet implemented I think a work around would not be very hard to make.

[per1234]

It seems it was fixed by f5ddfa8, but this issue and #187 were just never closed.

Try updating to the latest version of the Arduino Mbed OS Portenta Boards platform. The fix was released in 2.1.0

[hpssjellis]

@per1234

I am not getting any sensible values for either pulseIn() or pulseInLong() on the Portenta. The typical Arduino example does nothing

int pin = 7;
unsigned long duration;

void setup() {
  Serial.begin(9600);
  pinMode(pin, INPUT);
}

void loop() {
  duration = pulseIn(pin, HIGH);
  Serial.println(duration);
}

and a more advanced example loses the serial port

// pulseIn Example

const byte INPIN = 7;

void setup() {
   Serial.begin(9600);
   pinMode(INPIN, INPUT);
}

void loop() {
unsigned long res;

  Serial.print("Time: ");
  Serial.println(millis());
  Serial.println("Measuring...");
  Serial.flush(); // Needed since serial requires interrupts to operate.

  noInterrupts();
  res = pulseIn(INPIN, HIGH, 3000000UL);
  interrupts();

  if (res) {
     Serial.print("Time high (us): ");
     Serial.println(res);
  } else
     Serial.println("No signal present");

}

and pulseInLong() seems to also not give any useful values with a rangefinder

// pulseIn Example

const byte INPIN = 5;  // echo

void setup() {
   Serial.begin(9600);
   pinMode(INPIN, INPUT);
   pinMode(6, OUTPUT);     // trigger
}

void loop() {
unsigned long res;

  Serial.print("Time: ");
  Serial.println(millis());
  Serial.println("Measuring...");

  digitalWrite(D6, HIGH);
  delayMicroseconds(10); 
  digitalWrite(D6, LOW);   
  res = pulseInLong(INPIN, HIGH, 3000000UL);


  if (res) {
     Serial.print("Time high (us): ");
     Serial.println(res);
  } else
     Serial.println("No signal present");

}

Can anyone give an example of pulseIn() on the Portenta that gives any data?

[facchinm]

👋
A sensible sketch could be like

int pin = 7;
unsigned long duration;

void setup() {
  Serial.begin(9600);
  pinMode(pin, INPUT_PULLDOWN);
  analogWrite(6, 12);
}

void loop() {
  duration = pulseIn(pin, HIGH);
  Serial.println(duration);
  delay(10);
}

then short pins 6 and 7 and you should get 95us pulses correctly printed.
A couple of notes: pulseIn is effectively a blocking function, while Serial.print runs in another thread; if you don't insert any delay the print thread will slow down till it won't be able to execute anymore. Just inserting a delay() makes the scheduler give some space for the print to be executed.

This is only needed if you want to print the values; in case you just want to use them to trigger another function there's no need for the delay and the function can run at full speed.

About the rangefinder, I don't have an ultrasonic sensor at hand right now but I can get tested by a colleague and report back 😉

[hpssjellis]

@facchinm Thank you so much for helping with this little issue. Your code works perfectly. I should be able to solve my RangeFinder issue now, since I have a starting point.

Here is the type of rangefinder I have an HC-SR04 which works on other boards.

A few hours later.....

Since @facchinm proved pulseIn() works this problem should probably be in the arduino forum not here as an issue, but if anyone can get pulseIn() working with a rangeFinder that would be appreciated.

It should be so easy. The following code should work with the HC-SR04 range finder, but does not compile for me with the Nano33BleSense, and only shows zeros for both the RP2040 and Portenta. Very likely I have done something wrong but if anyone has any suggestions?

int myTriggerPin = 7;
int myEchoPin = 6;
unsigned long myDuration;

void setup() {
  Serial.begin(115200);
  pinMode(myTriggerPin, OUTPUT);
  pinMode(myEchoPin, INPUT_PULLDOWN);
}

void loop() {
  digitalWrite(myTriggerPin, LOW);
  delayMicroseconds(10); 
  digitalWrite(myTriggerPin, HIGH);
  delayMicroseconds(10); 
  digitalWrite(myTriggerPin, LOW);
  myDuration = pulseIn(myEchoPin, HIGH, 40000UL);
  Serial.println(myDuration);
  delay(10);
}

[hpssjellis]

I put this RnageFinder question on the Arduino forum at

https://forum.arduino.cc/t/portenta-ultrasonic-rangefinder-hc-sr04/875414