It is my understanding that you are trying to connect the Arduino ‘Uno’ and ‘Due’ serially to send data from one to other.
Currently, MATLAB has limited supported hardware for serialized data transmission across Arduino boards. The Arduino ‘Uno’ board in not supported for serialized Arduino Hardware connection.
As a workaround, you can try running the models sequentially, instead of simultaneously, i.e. first run the model for ‘Uno’, then run the model for ‘Due’ after disconnecting the previous one. This approach avoids the conflict between two models trying to access the same resources.
The following documentation has explanation and examples of ‘Send and Receive Serial Data Using Arduino Hardware’, with a list of supported Arduino Hardwares in Simulink:
I hope this helps.
