This is of particular concern when power is first applied to the circuit. One quirk with an XOR-based LFSR is that, if it happens to find itself in the all 0s value, it will happily continue to shift all 0s indefinitely (similarly for an XNOR-based LFSR and the all 1s value).
These articles are abstracted from the book Bebop to the Boolean Boogie (An Unconventional Guide to Electronics) with the kind permission of the publisher. Editors Note: This is the second in a three-part introduction to Linear Feedback Shift Registers (LFSRs).
