TIMER for the TI-84 Plus CE
TI84CalcWiz.com

A stopwatch and a countdown timer in one program.

Installing
  Send TIMER.8xp to your calculator, then run it from the
  PRGM menu.

Stopwatch
  Enter   start, pause, and pick up where you left off
  0       reset to zero
  Clear   quit. Your elapsed time stays on the home screen
          as a plain number of seconds.

Countdown
  Enter the minutes and seconds when asked. The screen
  flashes when the time runs out.
  Enter   stop early
  Clear   quit

Times are shown as hours:minutes:seconds. The timing comes
off the calculator's own clock, so a long run stays accurate.
