This paper presents the development of an application to propose complex exercises to students on a Moodle platform by connecting to an external server through LTI (Learning Tools Interoperability) protocol.The system has been applied to automatic grading of hardware descriptions made by students using the high level hardware description language VHDL. In this application the student has to upload his or her description in a Moodle platform and this description is simulated in another server with the appropriate simulation software. Thus, an immediate evaluation of the exercise is obtained with the need of additional software in the platform that hosts the Moodle platform and the student database, being another computer managed by teachers that performs simulations. The system is easily scalable to other fields different from digital electronics as Pspice.