There is a growing demand for software tools that can assist in designing, analyzing and validating embedded real-time system applications. Validating real-time constraints in embedded systems plays a major role in the development of reliable robust systems. Esterel - a synchronous language is widely used in the development of embedded systems and hardware/software codesign. In this paper, we describe a method that uses timed annotations for Esterel programs that makes it possible to predict the timing constraints required to be satisfied by the embedded system, or the runtime system. Using the specified annotations and powerful programming environment of Esterel we describe a method and a tool for validating the concrete realization relative to time-annotated Esterel specifications. Further, the method establishes time constraints to be satisfied by the concrete architectures for realizing the logical specification of the system. We shall illustrate the technique with examples and illustrate the structure of the tool using some of the existing code generation tools of the Esterel environment