Design the robot control machine discussed in Example $8\mathrm{.}17$ of the text with state assignment $A=\{Y_1,Y_2\}=00,B=\{Y_1,Y_2\}=01,C=\{Y_1,Y_2\}=10,$ and $D=\{Y_1,Y_2\}=11.$ Use clocked $($CLK$)$ rising$-$edge triggered D flip$-$flops with a clear $($CLR$)$ input for resetting the machine. Make it easy to follow your work and make your final gate$-$level design easy to understand; for any combinational logic you design, just use a two$-$level AND$-$OR MSOP implementation $($e$.$g$.,$ if you need to use an AND$3$ or an OR$3,$ just use those instead of breaking them up into smaller fan$-$in gates$).$ Show the whole circuit, meaning flip$-$flops, too, along with the clock and clear inputs. Also recall that complements are not free, so any needed inverters should also be included in the schematic $($but do note that complements of the present state variables are available at the output of the D flip$-$flops$).$ Make it easy to navigate your final gate$-$level schematic and try to minimize the "sea$-$of$-$wires" look that is so popular among so many of you. $($

We wish to design a finite$-$state controller for the robot of Fig. $8\mathrm{.}39$ so that it can find its way out of the maze shown in the figure.

The robot is to maneuver by turning whenever it comes in contact with pbstacle. On the nose of the robot is a sensor whose output $x=1$ when t is in contact with an obstacle; $x=0$ otherwise. The robot has two cor ines: $z_1=1,$ which turns the robot to the left, and $z_2=1$ which turns the othe right. When it encounters an obstacle, the robot should turn right no obstacle is detected. The next time an obstacle is detected, the robot sh furn left until the obstacle is cleared, and so on$.$

The robot controller requires four states as follows:

State $A=$ no obstacle detected, last turn was left

State $B=$ obstacle detected, turning right

State $C=$ no obstacle detected, last turn was right

State $D=$ obstacle detected, turning left