I am trying to get my head around the button matrix. I'm using a promicro clone and will have 3 x 74hc165's daisy chained together. At the moment I have one working on my breadboard which I'm happy with. This has used pins (b1, d2 and d3). I wish to have 4 x rotary encoders and up to 6 buttons. At the moment I have the rotary encoders working using 8 columns (pins e6, b4, d7, c6, d4, d0, d1, b2, b6) and row b5. These show as encoders 1 to 8 which is great. My problem seems to be when I add another row. Only 1 encoder works and 1 works on one button only. Are there set pins for rows and columns and do they need to be used in a certain order?