The prototypes of controllers realized so far utilize
PCs for interpreting the STEP-NC programs and for
generating the tool paths. Such PCs communicate with
the CNC machines by means of I/O boards. In this paper
we instead show how it is possible to realize a STEP-NC
compliant CNC controller using a low cost
microcontroller, embedded in the CNC machine. To this
end, we have characterized and decoupled the different
tasks involved in the machining process. Consequently it
has been possible to parallelize some tasks with the aim
of reducing dead times in the process execution and, at
the same time, allowing on-line machining inspection
and machining status feedback.