Question for Simon.monk

Hello R_

Well, the timer library uses millis() and only checks if anything needs doing when you call update(). So its not anything weird with timers etc. However, if you take too long in the loop to do other things (like serial which is slow) then the next update might not get called until after the due time of the next event. Which would lead to that event being skipped.

How frequent is the timer causing the problem?

Thanks for the reply!.

Once the call back is skipped it never executes again. I'm not sure if the call back isn't getting called or the timer simply isn't updating.

Basically I have 3 function calls in the loop;

Function 1 reads data coming in on the serial port and records the information to be used in the update callback.

Function 2 reads data coming from a Touch screen (software serial) and sends data out over serial. Note this is the serial send I plan to move into the update() call back.

t.update() which is set to execute every 500ms. This call back updates the information displayed on the LCD, this info is gathered from Function 1.

What happens is after random amounts of button presses on the LCD, Function 2, the LCD no longer updates it's information on screen which should be happening from the Call back. I can verify that the data is still received on the serial (Function 1) and I can verify that the information is still being received on the Software serial in Function 2. So the loop is still running, but the update callback fails to update the LCD as if the timer is no longer their.

If I power down and power back up, all the correct data is then updated to the LCD, including all my last button presses that weren't updated previously, and everything works again until I press a few touch buttons again. As long as I don't press buttons everything works fine.

I am fairly certain that it's being caused by the Serial Sends inside the function2, However I would expect only a skipped update now and again, not a total loss of t.update.

I would send you the code, but I'm not at liberty.

I suppose it could also be the Software Serial that is getting messed up somehow and data is not being sent to the LCD properly but I have a second program that is set up basically and almost identical to what I described above, only real difference is that there is only one button to press on the LCD. It has been running flawlessly for over 3 weeks here on my desk.

If moving the serial send inside the update callback fixes the problem, then it is something for you to be aware of that could happen. Just to note, using the delay() function in conjunction with your timer lib seems to induce the problem sooner.

Simon,

Also note as a quick check I removed the Timer.h lib and went back to the old method of;

unsigned long currTime;

unsigned long lastUpdate = 0;

unsigned long updateInterval = 500UL;

and in the loop

currTime = millis();

if(currTime - lastUpdate >= updateInterval)

  {

  UpdateAll();

  lastUpdate = currTime;

  }

and the problem is gone.

Simon,

Also note as a quick check I removed the Timer.h lib and went back to the old method of;

unsigned long currTime;

unsigned long lastUpdate = 0;

unsigned long updateInterval = 500UL;

and in the loop

currTime = millis();

if(currTime - lastUpdate >= updateInterval)

  {

  UpdateAll();

  lastUpdate = currTime;

  }

and the problem is gone.