This paper presents a hardware-software (HW-SW) partitioning algorithm to be used in HW-SW codesign of an embedded real-time system. The algorithm interacts with the period calibration method proposed in [Z, 5, 6] such that the period assignment and HW-SW partitioning of real-time tasks are considered in a single framework The partitioning algorithm makes use of three heuristics and one random transformation rule in order to quickly find a feasible HW-SW partition which most likely leads to the minimum HW cost design. As an experimental study, two partitioning algorithms, one that is based on the proposed heuristics and the other based on simulated annealing have been implemented. We have performed preliminary experiments and present the result.