Hi Michael,
Could you please take a look at this page of the MCUXpresso SDK API Reference Manual and confirm that the debug console is being initialized and enabled successfully?
MCUXpresso SDK API Reference Manual: Debug Console
It also has some typical uses cases and examples for the GETCHAR and SCANF functions, could you please take a look at them?
Please let me know if you continue to have issues with this.
Take care, best regards,
Sebastian