Change default value

Hello,

How can I change the default value of display posts ?

I would like to write [display-posts category=”my-category”] in a lot of pages and that it display always the same layout that I can change as I want by changing the default value.

For the moment I have to write : [display-posts category=”my-category” order=”ASC” posts_per_page=”30″].

The question is : how to change the default value ? For exemple, the default value of the post per page ?

Thank you