842 CHAPTER 16 / EXTERNALLY ASYNCHRONOUS/INTERNALLY CLOCKED
The two types of asynchronous programmable sequencers that are discussed in this
chapter are each, by their nature, unique approaches to multiple controller design. Beyond
these two approaches there are no other prospects. The one feature that accounts for the
success of an asynchronous programmable sequencer is the fact that each state-to-state
transition is predictable in some unique way. For the MAC module, it is a parity shift
between logically adjacent states, whereas for the one-hot approach it is a logic 1 shift
between one-hot coded states.
The applications of asynchronous programmable sequencers to multiple controller use
on a time-shared basis may appear to be highly specialized ...