You have to enter the full enum name, e.g.:
$Object/Status = MyModule.Status.Active
Or you can simply split on
btw. searching the documentation by 'enumeration' and/or 'split' would likely lead you to the right answer much faster.
In addition to Fabian's answer, you can always use the getKey() function to get it's Key value if you ever want to match the Enum value to a string, i.e. if you want to check whether a String value from a webservice field matches an Enumeration value A:
String inputString Enum EnumToCheck (ValueA, ValueB, ValueC) Expression for your Exclusive Split: trim(inputString) = getKey(EnumToCheck.ValueA)
You can also use getCaption() to get its caption (presentational value).
Also see Mendix docs: https://docs.mendix.com/refguide/enumerations-in-microflow-expressions