Why do I get a "Failed to connect to the target" error when trying to run in external mode with a TI F28379D ControlCard?

I have a Simulink model that I am trying to run on my TI F28379D ControlCard in External mode, but I keep seeing the following error:

 

Error occurred while executing External Mode MEX-file 'ext_comm': Failed to connect to the target. A time-out occurred while waiting for the connection response from the target. Possible reasons for the time-out:

a) The target is not switched on.

b) The target is not connected to your host machine.

c) The application for the model is not running on the target.

You might have clicked the Stop button. If the Run button is not dimmed, click it. Otherwise, click the Build button, which downloads and runs your application on the target.

Also, sometimes when I try to run the model it appears to almost begin running, but then I see some similar but different errors:

Error occurred while executing External Mode MEX-file 'ext_comm':

ExtSetTargetPkt() call failed on CLOSE.

Ensure target is still running

or,

Simulink cannot send a start packet to the mdoel 'myModel' running in external

mode, as the target has lost its connection with the host.

I have verified that all of my GPIO and COM port settings are correct, as described in this MATLAB Answers post:

https://www.mathworks.com/matlabcentral/answers/306258-simulink-external-mode-not-working-on-texas-instruments-c2000-launchpad-f28377s

I was even able to run the simple model from that post in external mode, but my real model will not work. What could be causing this?

Answer 1

[MathWorks Support Team]

The SW1 switch on the right-bottom of the board is supposed to be ON. The ON state can be inferred by label 1 and 0 around this switch. Please move both knobs on this switch towards 1.