The HT-Core provides an efficient way to build user specific devices by mapping the core and device modules to a programmable logic device connected to the HyperTransport Link. It provides a comfortable and efficient way to evaluate user specific devices 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).

The HT-Core is a non-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. Three queues are provided in each direction (see also block diagram):

• posted queue
• non-posted queue
• response queue

The HT400 interface delivers 3,2 GByte/s bidirectional bandwidth and a very low latency

• Very low latency device access
• suitable to connect a device to any AMD Opteron. processor node via a HTX connector
• up to 3,2GByte/s bidirectional bandwidth via an HT400 interface on FPGAs
• Configurable data width of max. 16bit bidirectional interface
• Max. internal clock frequency of 200MHz on FPGAs
• Internal data path width of 4x the link width (32/64bits)
• Convenient device interface at end of queues
• HyperTransport interface is implemented for Xilinx serializing IO cells
• Programmable core logic for the Xilinx Virtex-4 FPGA series and Altera Stratix 2 series
• Uses minimal hardware resources
• Fully synchronous design
• Efficient pipelined structure
• Synthesizable Verilog HDL code

• Verilog source code for mapping to Xilinx Virtex4 FX series FPGAs. Verified on the HTX-Board Computing evironment: Iwill DK8-HTX mainboard with LINUX-BIOS and HTX board.
  A constraint file in Xilinx .ucf file format describing the pinout is included.
  
• Verilog source for Altera Stratix 2 based platform is currently available on request only.

• The HTX-Board of the Computer Architecture Group at the Department of Computer Engineering, University of Mannheim.
• An Altera-based platform is to be supported soon.

The HT-Core is available under an open source license to any interested party. The acquiring party will be obligated to secure a HyperTransport technology license if and by the time any of the party's products based on the HT-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.