PORTB.0 is not used anywhere in the program (other than output from the Demo).
PORTB.5-7 are only used if the USB Status LED lines are uncommented (I left them commented). And they can be assigned to any pin, they don't have to be PORTB.5-7

CDC is USB, there's no RS232 connector.

In excel, use the Data | Import External Data | Import Data menu item to just plop your CSV file right into your spreadsheet. Then when the data changes, use Data | Refresh Data to update everything automatically.
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