TM4C1294NCPDT: GPIO output to GND

Outsider ALERT!

Much depends upon:

• the duration of that 'accident'
• the output current setting of the specific GPIO

I'd be wary of 'Space Launch' and/or 'Medical Implantation' - w/that MCU.    It should be 'quick/easy' to Toggle that GPIO - after placing a proper resistive load - and observing the resulting waveform.    Better still - add the same value load resistor to a GPIO on another Port (in case the pin & (even) port was damaged/impacted) - and toggle both (the 'accident') and your 'normal' GPIO - looking for differences.   Higher frequency toggle rates may prove best at revealing damage.    

It would be wise to measure the MCU's current draw - both @ idle and while toggling both (ports & pins).    A 2nd MCU should be subjected to the same exercise - and results compared...

Note too that 'some' report should have emerged - from the person who recognized/discovered the illegal connection.    Was the MCU 'hot' - or otherwise stressed?   (i.e. test code stuttered or otherwise failed)    These are 'pretty strong little beasts' - and often will survive - such abuse...   (especially when the 'offending current source' is the pin itself - no such 'survival' is likely - when an unlimited current arrives from an external source!)   

For the most demanding, critical & robust of applications - it proves 'SOP' to install current-limiting (protecting) resistors (usually a resistive network) upon each/every (especially external signal receiving) MCU GPIO pin(s)...