Resuming play is not used following halftime. Resuming play is when both teams are present and have been present but not responding to the signals to resume play.
After halftime, the team has 1 full minute after halftime expires before the T is charged. Until that time has elapsed, nothing is done.
See 10-1-5:
Allow the game to develop into an actionless contest, this includes the following and similar acts:
a. When the clock is not running consuming a full minute through not being ready when it is time to start either half.
b. Delay the game by preventing the ball.....See 7-5-1....for the resumption of play procudure to use.....The procedure is used prior to charging a technical foul in these specific situations
The specific situations referred to in part "b" of this rule only apply on timeouts, the intermission between the 1st and 2nd quarters, and the intermissions between the 3rd and 4th quarters. Not the halftime intermissions. Part "a" covers the return from halftime. If part b were to apply after halftime, part "a" wouldn't need to exist and couldn't be reached.