I am currently working on a project which requires hardware to PC interfacing (something like manipulating the keystrokes of the keyboard) , which is the recommended product to use to do such a project?
I recommend DIGI ConnectME. I have replaced our Coldfire-based control with this one and very satisfied with this tiny $52 box. You will have 11 lines for your control. I use, for example, 2 lines for I2C, 4 lines for SPI and 4 lines for JTAG. With JTAG, I control any FPGA-based hardware. If you are interested, I can share the code.