DianaPHP is an lighweight PHP framework with an ORM already included. You need to follow some rules to use this ORM, it's an active record pattern ORM, so not like Doctrine.
The framework itself implements an MVC work flow, as well as a dispatcher, where you can access the runtime at any point.
It focues on stuff, that you already know. So, getting into it and / or learning it is easy.
It requires PHP, Composer and a PDO supported database.
We / I will finish the framework as described in the readme.
Simply fork it and make a pull request.