This paper presents an abstract multi-clock oriented reasoning for the rapid prototyping of embedded applications executed on multiprocessor systems-on-chip (MPSoCs). The scheduling of applications on execution platforms composed of processors operating at various frequencies is described and analyzed with clocks. As in the static scheduling of synchronous dataflows (SDFs), requirements for admissible schedules are investigated, which come not only from expected application behavior, but also from execution platform. An algorithm is proposed to construct admissible schedules respecting identified requirements. It is then adapted to synthesize admissible schedules for adaptive system behaviors. The modeling, analysis and algorithms presented in this paper have been implemented in a prototype tool named CLASSY (standing for CLock AnalySis SYstem).