In a development of real-time embedded systems, one needs to consider at very early stages the platform on which the systems are deployed. An explicit specification of system resources enables in fact the specification of non-functional properties. In this paper, as an attempt to define a formal component model for real-time embedded systems, we propose to use resources as the first-class citizen at the contract level of components. We show that this explicit specification of resources enables not only the flexibility of the component contract but also the specification of several non-functional properties of systems. We show a way that the worst case execution time (WCET) and the concurrency of component methods are expressed and validated in terms of resources that are available to the component in question.