I understand that you're having some challenges with configuring the pull-up/pull-down resistors.
In MATLAB, there's a function called "configurePin" which can be used to enable the pull-up resistor for a specific pin.
This function is part of the MATLAB Support Package for Arduino Hardware.
Here's a brief example of how you can use it:
% Create a connection to your Arduino
a = arduino('COM4', 'Uno');
% Configure the internal pull-up resistor on pin D3
configurePin(a, 'D3', 'pullup');
The default state of the GPIO pins can be either pull-up or pull-down depending on the specific pin. The pull-up/pull-down state is not set for some pins, which means they will be floating until you explicitly set the pull-up or pull-down.
Refer to the following MathWorks documentation for more details about the configure in:
Hope it Helps !
