The cHT-Core allows the user to build devices with coherent caches or adapt custom processors to the coherent interface of the coherent HyperTransport Link. The cHT-Core is a coherent HyperTransport cave device. A cave is an endpoint device in a HyperTransport chain. The core is a low latency device with a queue based application interface. Four queues are provided in each direction:

• posted queue
• non-posted queue
• response queue
• probe queue

The cHT-Core provides a comfortable and efficient way to evaluate user specific processors connected to the HyperTransport connector standardized under the name HTX-Connector. It can be used in conjuction with the HTX-Board (see HTX-Board data sheet). There the cHT core can be mapped to the high performance FPGA (Xilinx Virtex FX60).

• Very low latency device access
• Compliant with the coherent HT I/O Link Specification
• suitable to connect a coherent device with cache or a processor with coherent cache to any AMD Opteron processor
• HT interface is implemented for Xilinx serializing IO cells
• Programmable core logic for the Xilinx Virtex-4 FPGA series
• Uses minimal hardware resources
• Test and debug configuration files for Cadence Simvision
• Fully synchronous design
• Efficient pipelined structure
• Synthesizable Verilog HDL code

Verilog source code verified with a Virtex FX60 on the HTX-Board.
Computing environment: Iwill DK8-HTX mainboard with LINUX-BIOS.
A constraint file in Xilinx .ucf file format describing the pinout is included.

• The HTX-Board of the Computer Architecture Group at the Department of Computer Engineering, University of Mannheim.

The cHT core is only available under the coherent HyperTransport License from AMD. Please contact AMD for further details about licensing and delivery of the core. The acquiring party will be also obligated to secure a HyperTransport technology license if and by the time any of the party's products based on the cHT-Core is openly promoted or sold. A royalty-free HyperTransport technology license can be acquired by simply becoming a member of the HyperTransport Technology Consortium. Complete information about HyperTransport Consortium membership classes, benefits, fees and application guidelines can be found here.