This paper presents the AsmM, a metamodel for Abstract State Machines developed by following the guidelines of the Model Driven Engineering. The AsmM represents concepts and constructs of the ASM formal method in an abstract way, it is endowed with a standard visual notation, and it is intended easy to learn and understand by practitioners and students. From the AsmM a concrete syntax is also proposed and a standard interchange format for a systematic integration of a number of loosely-coupled ASM tools is derived. The metamodelling advantages for tool interoperability are shown by referring to the experience in making the ATGT, an existing tool supporting test case generation for ASMs, compliant to the AsmM
