Errors

The Top 20 Errors in VHDL

.. Most Common VHDL Errors

Ref. VHDL Golden Reference, Dulous

This is a list of the most common VHDL errors. The Top 10 account for about

40% of all errors. The Top 20 account for about 60% of all errors.

1-10

- Missing or misplaced begin in architecture / process / subprogram

- Swapping <= := and =

- Missing or extra end if / end case / end loop / end process etc...

- Wrong quotes around characters / strings / integers

- Incompatible types in assignments / operators

- Missing or extra ; at end of declaration / statement

- Misspelt identifier

- Undefined signal / variable / constant

- Missing library / use

- Wrong separator , / ; / : / .

11-20

- Missing sensitivity list / wait statement in process

- Sensitivity list and wait statement in same process

- Same name used twice

- elseif or endif (instead of elsif and end if respectively)

- Using the wrong user defined identifier

- Extra / missing / mistyped character

- Missing signals in sensitivity list

- Mismatched vector lengths

- Using a reserved identifier

- Reading out ports

24 August 2012

40%

20%

40%

Errors

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Other Errors