|Summary |Design Units |Sequential Statements |Concurrent Statements |Predefined Types |Declarations |
|Resolution and Signatures |Reserved Words |Operators |Predefined Attributes |Standard Packages |
This is not intended as a tutorial. This is a quick reference guide to find the statement or statement syntax you need to write VHDL code. VHDL is case insensitive, upper case letters are equivalent to lower case letters. Reserved words are in lower case by convention and shown in bold in this document. Identifiers are simple names starting with a letter and may have letters and digits. The underscore character is allowed but not as the first or last character of an identifier. A comment starts with minus minus, "--", and continues to the end of the line. Indentation is used for human readability. The language is free form with the characters space, tab and new-line being "white space."
Each item has:
a very brief explanation of possible use.
a representative, possibly not complete, syntax schema
one or more samples of actual VHDL code.
In the syntax statement [ stuff ] means zero or one copy of "stuff".
In some cases "optional" is used to not clutter up the syntax with [[][]].
In the examples, assume the appropriate declarations for identifiers,
appropriate enclosing design unit and appropriate context clauses.