Inertial and Hodge-Tate weights of crystalline representations

Let K be an unramified extension of Q(p) and rho : G(K) -> GL(n)((Z) over bar (p)) a crystalline representation. If the Hodge-Tate weights of rho differ by at most p then we show that these weights are contained in a natural collection of weights depending only on the restriction to inertia of (rho) over bar = rho circle times((Z) over barp) (F) over bar (p). Our methods involve the study of a full subcategory of p-torsion Breuil-Kisin modules which we view as extending Fontaine-Laffaille theory to filtrations of length p.