28 March 2020

Difference between VHDL and Verilog

What is VHDL?

VHDLVHSIC-HDL) stands for very high speed integrated circuit hardware description language. VHDL is a hardware description language, It is used in electronic design automation to describe digital and mixed-signal systems such as field-programmable gate arrays(FPGA) and integrated circuits(ICs). VHDL may also be used as a general-purpose parallel programming language.

What is Verilog?

Verilog is a hardware description language. Verilog is used for describing a digital system like a network switch or a microprocessor or a memory or a flip flop.  It means by using an HDL we can describe any digital hardware at any level. The design which is described in HDL is independent of the technology, It very easy for designing and also for debugging, and is normally more useful than schematics and particularly for large circuits. 

The main key difference between VHDL and Verilog are listed below:

  • VHDL may be preferred because it is allowed a multitude of the language of defined datatypes, Verilog may be preferred because of its simplicity. 
  • VHDL is harder to learn ADA-like, Verilog easier to learn C-like.
  • Complication should not be an issue in VHDL, while in Verilog take care of compilation order.
  • The library is present in VHDL but in Verilog no concept of a library.
  • Procedures and functions may be placed in the package, While in Verilog no concept of package.
  • VHDL allows the function to be written inside in a body while in Verilog function is not allowed to be written inside in a task body.
  • Verilog is easier to learn compared to VHDL.
  • Verilog is a simple datatype, VHDL has more complex datatypes.
  • VHDL manage the large design, Verilog does not manage the large design, because of no concept of package.
  • VHDL is older than Verilog, Verilog is a newer language than VHDL. 
  • VHDL has a strong type of datatype, Verilog has a weak datatype.
  • VHDL allows concurrent procedure calls, Verilog does not allow concurrent task call.
  • A unary reduction operator is not present, the Mode operator is present. Unary reduction operator present in Verilog, no concept of package.
  • VHDL supports multidimensional array, Verilog doe not support multidimensional array.
  • VHDL generate statement replicates the number of instances, Verilog generates statement is not present in Verilog.