STEP-NC is a new model for data transfer between
CAD/CAM and CNC that allows specifying machining
process rather that tool motion with respect to the
machine axes. STEP-NC CNC controllers are a new
breed of CNC controllers that allow using this high-level
model for a seamless integration in the CAD-CAM-CNC
chain. Various prototypes of STEP-NC CNC controllers
have been developed so far, mainly based on industrial
PCs. In this paper we instead show how it is possible to
realize a STEP-NC CNC controller using a low cost
microcontroller, embedded in the CNC machine; this
goal has been obtained by accurately parallelizing the
tasks involved in the machining process. More precisely,
this paper presents the design and realization of an
embedded system able to control a CNC machine with
two degrees of freedom, to machine STEP-NC part
programs and to perform also other high level activities.