Quartus

VHDL Attribute Specification warning in <location>: ENUM_ENCODING attribute for object with enumeration type <name> contains one or more encoding values that are not valid -- ignored encoding values

CAUSE:

In an Attribute Specification at the specified location in a VHDL Design File (.vhd), you specified the ENUM_ENCODING attribute for an object with the specified enumeration type, which you declared for a state machine. However, the expression in the Attribute Specification contains encoding values of different lengths. For example, in the following Attribute Specification, the encoding value "1" is not the same length as the encoding values "01", "10", and "00":

ATTRIBUTE ENUM_ENCODING OF count_state: TYPE IS "1 01 10 00"

All the encoding values in an attribute expression must be the same length. As a result, the Compiler ignored all the encoding values in the expression.
ACTION: Make sure all the encoding values in the expression of an Attribute Specification are the same length.
NOTE: The ENUM_ENCODING attribute is Quartus II-specific, and may not be available with other VHDL tools.

See also:

Manually Specifying State Assignments
Section 5.1 of the IEEE Std 1076-1993 IEEE Standard VHDL Language Reference Manual

- PLDWorld -

 
Created by chm2web html help conversion utility.