Sec. 1. When the defendant in a criminal case intends to interpose the defense of insanity, he must file a notice of that intent with the trial court no later than:
(1) twenty (20) days if the defendant is charged with a felony; or
(2) ten (10) days if the defendant is charged only with one (1) or more misdemeanors;
before the omnibus date. However, in the interest of justice and upon a showing of good cause, the court may permit the filing to be made at any time before commencement of the trial.