In making homemade pasta some recipes call for semolina flour. There are two types of semolina that I know of one is the course grind and one is the fine grind which they call durum flour. Both are from semolina wheat. So the question is when they call for semolina flour which one do you use ?
There is not one correct answer to your question. I've seen recipes with, and have used, both. So, it depends on the type of pasta. A recipe for capunti (a hand rolled pasta from Puglia) that I enjoy, uses 1/2 semolina and 1/2 durum... while an extruded pasta noodle might use all semolina. You might be guided by identifying the type of pasta, and its region of origin, to see what is typical. However, I would have to assume that when a recipe calls for semolina flour it generally means the course grind version.