A focus on VHDL

Alun Williams

Wednesday 01 August 2007 17:25

VHDL is a hardware description language for hardware engineers to define digital circuitry, targeting CPLDs (complex programmable logic device) and FPGAs (Field-programmable gate arrays). It was created by the US Department of Defense in the 1980s.

Often described as a programming langauge, VHDL is strongly-typed (constraining the actions that can be carried out on particular types of variables) with support for parallelism and an extended set of Boolean operators.

Another hardware description language would be Verilog.

VHDL is a nested acronym, standing for VHSIC (Very-High-Speed Integrated Circuit) Hardware Description Language

In the following, we bring together resources from Electronics Weekly to provide more detailed reference information about VHDL.

ELECTRONICS WEEKLY NEWS ON VHDL

MCU design for hard real-time problems
Researchers at Columbia University in New York and the University of California at Berkeley have developed a microcontroller architecture that will tackle the problems of programming systems for hard real-time performance. The resulting designs used 78 lines of assembly code rather than 450 lines of VHDL which would be needed for a hardware controller.

System Verilog language warning from IP expert
An industry expert has voiced concerns over System Verilog, the hardware description language touted as a replacement for VHDL and Verilog, describing it as "risky".

Xilinx offers faster FPGA design
Making changes to a design's VHDL or Verilog normally forces the whole design to be recompiled, but Xilinx has updated its FPGA design software with a system that speeds up recompilation of designs.

Protecting your IP just got simpler
There was a rare outbreak of agreement at the Design Automation Conference this year when the FPGA tools company Synplicity announced a free, non-proprietary IP encryption flow and the idea got the thumbs up from EDA companies, IP vendors, and FPGA companies alike.

Tenison wraps IP models for safe distribution
Electronic design automation firm Tenison has made a significant enhancement to its model creation tools, adding security and legal frameworks. Its VTOC tool takes Verilog or VHDL code and turns it into a higher level model.

ELECTRONICS WEEKLY ANALYSIS OF VHDL

Can UML-based design cut the mustard?
"With a tool like Altium Designer you have a very fluid environment to allow you to move between the different domains of board, FPGA and software, so even if you are using a high level tool you can still come down and represent that with scalable blocks that can be a transistor or 250,000 line of VHDL."

VHDL program enables PCI-arbiter core
This Circuit Design Idea describes a VHDL implementation of a PCI 2.2-bus arbiter.