How do I know what feedback taps to select in order to obtain an m-sequence?
In short, any combination of feedback taps will provide a recursive sequence, regardless of which taps you choose. However, only certain combinations of feedback taps will result in maximal-length sequences, called m-sequences. These are the longest sequences possible given a specific shift register size, and they have many desirable properties. If the register size is m stages, the length of the m-sequence will be 2m-1. Tables of feedback sets for m-sequences are given in an article we wrote on Linear Feedback Shift Registers. We think you will find this to be a handy reference on sequence generators.
