timer period resolution issue

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Rakesh
Rakesh on 7 Feb 2023
Commented: Rakesh on 11 Feb 2023
Hi all,
I am using MATLAB 2022b version.
I am developing a script which sends the packet at every 10 msec.
I configured the timer in free running mode with the period of 10 msec and then started storing the time stamp value in an array at each interrupt in my timer ISR.
Then plotted the difference between the time stamp values ,we are observing that the timer interrupt is varying from 7msec to 15msec.
But when the same calculations are carried out for 1sec period, we have observed that max error was 2msec .
Can you please provide me a wayout to configure the timer at 10 msec period.

Answers (2)

Dr. JANAK TRIVEDI
Dr. JANAK TRIVEDI on 7 Feb 2023
% Start timer
t = timer('TimerFcn',@timerISR, 'Period', 10/1000, 'ExecutionMode', 'fixedRate');
start(t);
% Timer ISR function
function timerISR(~,~)
tic; % Start measuring processing time
% Code to store time stamp value in an array
processingTime = toc; % End measuring processing time
set(t,'Period',(10 - processingTime)/1000); % Adjust timer period
end
  1 Comment
Rakesh
Rakesh on 11 Feb 2023
Hi Janak,
Thanks for the reply,
I have checked with the same configuration,
When the period is given in seconds , the above code works fine,
But when the same is checked for less resolution i.e. msec , I am observing this issue.
Regards,
Rakesh

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Amal Raj
Amal Raj on 7 Feb 2023
Edited: Amal Raj on 7 Feb 2023
Hi Rakesh,
You can check out timer.
ExecutionMode can be set to 'fixedRate', so that the timer generates events at a fixed rate.
  1 Comment
Rakesh
Rakesh on 11 Feb 2023
Hi Amal,
Thanks for the reply,
I had set the executionmode to fixedrate only,
The above observations is with executionMode Fixedrate .

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