Using Port DD as GPIO on MCF5282
The datasheet makes it sound like you need to disconnect the on-chip debugger from port DD before you can use it as a normal port.

26.4 Functional Description
26.4.1 Overview
[...]
In single-chip mode, all pins are configured as digital I/O by default, except for debug data pins (DDATA[3:0]) and processor status pins (PST[3:0]). These pins are configured for their primary functions by default in all modes.

— MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3, § 26, p. 27
In most MCUs I've used, alternate functions usually override GPIOs, which has the lowest priority.