VHDL Synthesis Support

Quartus® Prime synthesis supports the following VHDL language standards:

  • VHDL 1987 (IEEE Standard 1076-1987)
  • VHDL 1993 (IEEE Standard 1076-1993)
  • VHDL 2008 (IEEE Standard 1076-2008)
  • VHDL 2019 (IEEE Standard 1076-2019)1

The Quartus® Prime Compiler uses the VHDL 1993 standard by default for files that have the extension .vhdl or .vhd.

Note: The VHDL code samples follow the VHDL 1993 standard.

The Quartus® Prime software support for VHDL is described for the following categories of VHDL constructs. These sections match those in the IEEE Std 1076-1993 version of the IEEE Standard VHDL Language Reference Manual. The constructs of the IEEE Std 1076-2008 version of VHDL are listed in the About VHDL topic.


Support for each VHDL construct is described with one of the following terms:

  • Supported— The Quartus® Prime software offers full support for the construct.
  • Not-supported— The construct cannot be used in a VHDL Design File (.vhd) Definition. If used, the construct causes an error when the Quartus® Prime software compiles the file.
  • Ignored— The construct can be included in a VHDL Design File, but it is ignored by the Quartus® Prime Compiler.
1 Only a subset of the features introduced by in VHDL 2019 are supported: Interfaces and Conditional Analysis.