17th century doors in their simplest form were usually made up of vertical planks on horizontal battens or ledges (never ledged & braced in a Z pattern as later 20th century doors) nailed together with the nail ends cleated over.
Many counties having their own distinct style.The boards or planks may be simply butt jointed,rebated or have loose tongues.Often the board edges being beaded to flaunt the joint.
Generally the wider the plank the earlier the door,usually three or four on a normal width door (typically 32-33" x 68-72").
Material by this time would be pine,with a very low percentage being oak,certainly in the more basic house.Oak would have been used in preference though for the front door, and often of double thickness with horizontal boarding on the inside to prevent draughts as well as giving extra strength.
Panelled doors were to be found only in grander properties,often being false panels applied to the boards.
Original doors of this period are,for obvious reasons hard to find, particulary made of oak.