11.1.4 General Handling Guidelines for Unused CMOS-Type Pins

To avoid potentially damaging current caused by floating CMOS input-only pins, TI recommends that unused DLPC150 controller input pins be tied through a pullup resistor to its associated power supply or a pulldown to ground. For DLPC150 controller inputs with an internal pullup or pulldown resistors, it is unnecessary to add an external pullup or pulldown unless specifically recommended. Note that internal pullup and pulldown resistors are weak and should not be expected to drive the external line. The DLPC150 implements very few internal resistors and these are noted in the pin list. When external pullup or pulldown resistors are needed for pins that have built-in weak pullups or pulldowns, use the value 8 kΩ (max).

Unused output-only pins should never be tied directly to power or ground, but can be left open.

When possible, TI recommends that unused bidirectional I/O pins be configured to their output state such that the pin can be left open. If this control is not available and the pins may become an input, then they should be pulled-up (or pulled-down) using an appropriate, dedicated resistor.