  We present a preliminary calculation of the charmed meson spectrum using the
2+1 flavor domain wall fermion lattice configurations currently being generated
by the RBC and UKQCD collaborations. The calculation is performed using the
3-parameter, relativistic heavy quark action with nonperturbatively determined
coefficients. We will also demonstrate a step-scaling procedure for determining
these coefficients nonperturbatively using a series of quenched, gauge field
ensembles generated for three different lattice spacings.
