# Making aysnchronous sequential circuits hazard free

The problem I am stuck at requires me design a hazard free asynchronous sequential circuit for a given problem description. I have followed the routine steps as follows:

• I have obtained the primitive flow table from the problem description
• I have reduced the flow table using state minimisation routines of incompletely specified FSM
• I have assigned the output symbol preventing glitches
• I have done the state assignments of the reduced flow table

Let us assume that I require three secondary variables $$y_1,y_2 ,y_2$$ for the state encoding.

Now I have the resulting flow table. I am stuck at how I should proceed for hazard checking. I know the general procedure of checking and removing static and dynamic hazards, given a function and some transitions.

In this problem,

• For static hazards, I guess, I should check the KMap for each $$y_1 ,y_2,y_3$$ and thereby check for adjacent $$1’s$$. Am I right?
• For dynamic hazards , I really have no clue how to proceed.Descriptive answers would be very helpful