Mismatches in acquired digital signal in Simulink using Arduino Due

Hi,

I was doing some simple signal acquisition models in Simulink (Matlab ver. R2017b) with Arduino Due board. I was giving a unipolar square wave (250 Hz) from a function generator to pin 8 of the Arduino Due microcontroller. The 'digital input' block in Simulink is used and the output of the block is connected to a scope. In the 'digital input' block, the sample time is set as 0.001.

Now, when I'm observing the signal, in the scope, it is not at all replicating the input. On the other hand, when I ran the exact same code in Arduino Uno, with the same square wave, the scope is showing the proper output. I've attached couple of pictures of scope outputs, which demonstrate the two scenarios.

Can anybody tell, what can be reason of this mismatch?

Looking forward to some solution of this problem.

[Roshni Garnayak]

Have you selected the right 'Hardware Board' in 'Model Configuration Parameters' while working with Arduino Due? What solver are you using for Uno and Due?

[TAPABRATA SEN]

Hi, Yes the hardware board I selected properly.

And regarding the solver, I selected 'fixed-step' type and 'auto' solver option.

Please let me know, what you think.

[Roshni Garnayak]

Please create a service request at https://www.mathworks.com/support/contact_us.html

Answer 1

[Arun Kumar]

Hi,

I think the issue is due to the operating voltages. Due is ARM based board and works at 3.3V while Uno(and other AVR boards) operate at 5V.

I suggest checking the output voltages on the function generator. For Due, max should be 3.3V.

HTH.