4-bit fibonacci LFSR. see https://en.wikipedia.org/wiki/Linear_feedback_shift_register
Sets the rate of the trigger that will calculate a new value.
Initial seed. Use 8 (2r1000) to get the common sequence: [[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [1, 0, 0, 1], [1, 1, 0, 0], [0, 1, 1, 0], [1, 0, 1, 1], [0, 1, 0, 1], [1, 0, 1, 0], [1, 1, 0, 1], [1, 1, 1, 0], [1, 1, 1, 1], [0, 1, 1, 1], [0, 0, 1, 1], [0, 0, 0, 1]]
8 (2r1000)
[[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [1, 0, 0, 1], [1, 1, 0, 0], [0, 1, 1, 0], [1, 0, 1, 1], [0, 1, 0, 1], [1, 0, 1, 0], [1, 1, 0, 1], [1, 1, 1, 0], [1, 1, 1, 1], [0, 1, 1, 1], [0, 0, 1, 1], [0, 0, 0, 1]]
Pseudo random waveform 0/1.