Engineering Digital Design

716 CHAPTER 14 / ASYNCHRONOUS STATE MACHINE DESIGN AND ANALYSIS

Fig. 14.27:

¯

AB → AB, AB = I

cb

⊆ f

b

= A,

¯

AB = I

ba

⊆ f

c

=

¯

AB, I

cb

 f

ab

.

Only a single change in the initiator is indicated in c → b and b → a with B held constant.

Here, state 11 (state c) is the origin state, A is the initiator input, the intended path is

11 → 01 (c → b) , the E-hazard (error) path is 11 → 01 → 00, y

0

is the first invariant,

and y

1

is the second invariant.

The remaining requirements for E-hazard formation in the FSM of Fig. 14.28a are

obtained from Eqs. (14.20) and Fig. 14.29 in accordance with Fig. 14.27 and the indirect

path (IP) requirements given previously.

1. A delay t

E

placed on the initiator A input to the first invariant y

0

causes a critical

race to the race gate RG

E

between ...