You changed from "parallel port project" to "parallel or serial port".
OK, you have to nail this down some. What _EXACTLY_ are looking to do here? Mechatronics is a very wide category. Obviously you have to (want to?) use a PC in the project. Is this a school project? Personal?
When you program it, you have to decide if it's standalone (independent of the PC) or works with another computer.
You could literally have the PC's parallel port drive transistors or a driver chip like the ULN2803 to control DC motors (or servos or steppers), thus eliminating the need for an extra microcontroller. You can do this in Visual BASIC, or any number of BASICs, old and new.
If the PC works with a microcontroller, then you must first program the MCU with the PC. This is after you select the MCU model to use. That determines which compiler you write the MCU's program in and, in most cases, which programming method you use: low-voltage-versus high-voltage, supported models of device programmers, onboard vs offboard... the list of considerations is long.
There is a motor driver board available that does a lot with motors of all kinds:
**broken link removed**
You name it, it drives it. All the way up to 9 Amps per channel, if needed! Cost is $25. You have to buy a small USB programmer dongle, which is another $15, so $40 total. The programmer can be used for serial comms after programming is finished. The page above can take you to demo code that controls several kinds of motors. It has servo headers on board that can be used with offboard sensors. Get the data sheet and read up on it.
It has a BASIC that is free for the download. It's quite powerful, and real easy to write programs in.
So, get back to us with what you want to do.
kenjj