Format of AT.COM event record:
Offset	Size	Description	)
 00h	BYTE	in-use flag (00h free, 01h in use, FFh end of array)
 01h	BYTE	day of date on which to trigger
 02h	BYTE	month of date on which to trigger
 03h	BYTE	trigger time, minute
 04h	BYTE	trigger time, hour
 05h	WORD	offset of command to be executed