Title :
Pass-transistor asynchronous sequential circuits
Author :
Whitaker, Sterling R. ; Maki, Gary K.
Author_Institution :
NASA VLSI Hardware Accel. Center for Space Res., Idaho Univ., Moscow, ID, USA
Abstract :
Design methods for asynchronous sequential pass-transistor circuits, which result in circuits that are hazard- and critical-race-free and which have added degrees of freedom for the input signals, are discussed. The design procedures are straightforward and easy to implement. Two single-transition-time state assignment methods are presented, and hardware bounds for each are established. A surprising result is that the hardware realizations for each next state variable and output variable is identical for a given flow table. Thus, a state machine with N states and M outputs can be constructed using a single layout replicated N+M times.<>
Keywords :
VLSI; asynchronous sequential logic; field effect integrated circuits; integrated circuit technology; integrated logic circuits; NMOS pass network; asynchronous sequential pass-transistor circuits; critical-race-free; degrees of freedom; design procedures; hardware bounds; hardware realizations; hazard free; pass-transistor logic; single layout replicated; single-transition-time state assignment methods; state machine; Asynchronous circuits; Clocks; Driver circuits; Flip-flops; Hardware; Hazards; NASA; Sequential circuits; Signal design; Very large scale integration;
Journal_Title :
Solid-State Circuits, IEEE Journal of
