MATLAB Programming Fundamentals - MathWorks

Handling Timer Queuing Conflicts

At busy times, in multiple-execution scenarios, the timer may need to add the timer

callback function (TimerFcn) to the MATLAB execution queue before the previously

queued execution of the callback function has completed. You can determine how the

timer object handles this scenario by setting the BusyMode property to use one of these

modes:

In this section...

“Drop Mode (Default)” on page 27-10

“Error Mode” on page 27-11

“Queue Mode” on page 27-13

Drop Mode (Default)

If you specify 'drop' as the value of the BusyMode property, the timer object adds the

timer callback function to the execution queue only when the queue is empty. If the

execution queue is not empty, the timer object skips the execution of the callback.

For example, suppose you create a timer with a period of 1 second, but a callback that

requires at least 1.6 seconds, as shown here for mytimer.m.

function mytimer()

t = timer;

t.Period = 1;

t.ExecutionMode = 'fixedRate';

t.TimerFcn = @mytimer_cb;

t.BusyMode = 'drop';

t.TasksToExecute = 5;

t.UserData = tic;

start(t)

end

function mytimer_cb(h,~)

timeStart = toc(h.UserData)

pause(1.6);

timeEnd = toc(h.UserData)

end

27 Program Scheduling