I was not capable of verifying the codes that I modified because I had problems understanding how the output signal waveform should and should not be. I was frustrated with myself that I could not even understand the simple communication protocol, GPIO. Dr. Shawn was also angry and had to explain how it works in which the Wishbone bus and the GPIO signal must be observed to confirm whether or not the output works according to its inputs. Dr. Shawn emphasized that an engineer should be responsible and capable of verifying their own work.
I started making testbenches and modified it according to the aspects that I changed in the codes. I modified the testbench and run it again and again to see the difference when the inputs had changed. The test was also made with other variable parameters and possible outcomes of the design. It was quite a repetitive task demanding one to be meticulous. From there, I could then observe how it worked, how it must work and how it should not work.
Now I really understood how complex a testing can be, sometimes even more complicated than the design itself thus requiring more time and effort. It requires one to have a strong basic on the chip designed as well as the approach of testing to ease the verification process and reducing the time consumed.