This GitHub repository hold DFDL schemas that model ISO8583 credit/debit card data. There are DFDL schemas for the two most popular release of the standard:
This is a public repository that allows anybody to view the content. If you would like to contribute to this repository, email the address on the organisation home page.
Data Format Description Language (DFDL, often pronounced daff-o-dil), published as an Open Grid Forum Proposed Recommendation in January 2011, is a modeling language for describing general text and binary data in a standard way. A DFDL model or schema allows any text or binary data to be read (or "parsed") from its native format and to be presented as an instance of an information set. The same DFDL schema also allows data to be taken from an instance of an information set and written out (or "serialized") to its native format.
If you are new to DFDL a good place to start is the DFDL page on IBM developerWorks. This contains links to DFDL implementations, tutorials and videos.