In this paper we present a framework integrating speci cation and scheduler generation for real-time systems. In a rst step, the system, which can include arbitrarily designed tasks cyclic or sporadic, with or without precedence constraints, any number of resources and CPUs is speci ed as a timed Petri-net. In a second step, our tool generates the most general nonpreemptive online scheduler for the speci cation, using a controller synthesis technique.