Just before the flip flops of the counter are cleared (that is when the counter is in the last used state) the flip flop outputs Q0 , Q1 and Q2 are made to pass through a full adder and the output of FULL ADDER is given to JK FLIP FLOP i.e, SUM to J and CARRY to K input of the JK F.F.
The JK F.F enters into the :
a.HOLD STATE
b.SET STATE
c.RESET STATE
d.TOGGLE STATE.
