About CHREC XML
CHREC XML is a set of vendor extensions to the hardware intellectual property (IP) standard IP-XACT developed by the SPIRIT Consortium and maintained by Accellera. IP-XACT defines the meta-data elements required to represent IP cores. The IP-XACT specification requires that IP be connected to a standard bus and contains no notion of interface protocol. The CHREC XML extensions define the elements needed to extend this specification to more arbitrary cores.
CHREC XML extends IP-XACT in three primary ways:
- Interface Details: Extensions are made to describe the behavior of cores that fit the homogeneous synchronous dataflow model of computation. This means that cores that are described with these extensions have a constant data introduction interval and a constant pipeline depth or latency.
- High-level data types: The ability to attach numerical "high-level" types is added. Ports can reference a parameterizable type that is defined in the IP description file. The types supported by this extension set include:
Parameterization: Some classification of ports and further ability to parameterize extensions and ranges is added.
- Bit Vector
- Floating Point
- Fixed Point
Obtaining CHREC XML
The schema can be obtained here.
Several published papers discuss the usage of CHREC XML including the following:
- A. Arnesen, K. Ellsworth, D. Gibelyou, T. Haroldsen, J. Havican, M. Padilla, B. Nelson, M. Rice, and M. Wirthlin, "Increasing Design Productivity Through Core Reuse, Meta-Data Encapsulation, and Synthesis," Proc. of International Conference on Field-Programmable Logic and Applications (FPL), Aug. 31 - Sep. 2, 2010. (Here)
- A. Arnesen, N. Rollins, and M. Wirthlin, "A Multi-Layered XML Schema and Design Tool for Reusing and Integrating FPGA IP," Proc. of Intl. Conference on Field-Programmable Logic and Applications (FPL), Prague, Czech Republic, Aug. 31 - Sep. 2, 2009. (Here)
- N. Rollins, M. Wirthlin, and A. Arnesen, "An XML Approach to Facilitating IP Core Reuse," Proc. of National Aerospace & Electronics Conference (NAECON), Dayton, OH, July 16-18, 2008. (Here)