$[15$M$]$ Consider the scenario where four stepper motors drive the wheels of a Mars Rover. Assume that each

wheel has a radius of $\frac{3}{}$ meters and all the stepper motors have a $1\mathrm{.}8$ degrees stepping angle when used in

full$-$step model of operation. Since all wheels are to move synchronously, all four stepper motors receive the

same excitation sequence from Port A of $8255.$ All unused ports are declared to be output ports and $8255$ is

to be used in Mode $0.$ Consider the following code executed by $8086$ to carry out the above task. Answer

the following questions in the given box ONLY. Note that the circumference of a circle having radius $r$ is

$C=2r.$ Assume that a sub$-$routine named "DELAY" is available to generate the required delay.

$.$MODEL SMALL

$.$DATA

FORWARD DB $?$

BACKWARD DB $?$

$.$CODE

$.$STARTUP

CR EQU $0$C$6$H ; Port address of Control Register

PA EQU OCOH ; Port address of Port A

MOV AL$,$ CW

OUT CR$,$ AL

MOV CX$,N,$;$N$ is immediate data

MOV FORWARD, $N_1$;$N_1$ is immediate data

MOV BACKWARD, $N_2$;$N_2$ is immediate data

MOV AL$,88H$

AGAIN:

MOV BL$,$ FORWARD

UP$1$:

ROR AL$,1$

OUT PA$,$ AL

CALL DELAY

DEC BL

JNZ UP$1$

MOV BL$,$ BACKWARD

UP$2$:

ROL AL$,1$

OUT PA$,$ AL

CALL DELAY

DEC BL

JNZ UP$2$

LOOP AGAIN

$.$EXIT

END

a$.[3$M$]$ What should be the value of $"$CW$"\text{'}($in

Hexadecimal number system$)$ given in the code

for intended operation of the system, as

described?

$CW=$

b$.[4$M$]$ Suppose $N_1=5$ and $N_2=4$ in the given

code. What is the value of $N($in decimal number

system$)$ such that the Mars Rover traverses a

distance of $30$ meters in the forward direction

before halting?

$N=$

c$.3M$ For the Mars Rover to traverse in the

backward direction, how should $N_1$ and $N_2$ be

related to each other? Provide the inequality.

d$.5M$ For the Mars Rover to traverse a distance of

$30$ meters in the backward direction before

coming to a halt, what equation $($in terms of $N_1$

and $N_2)$ should be satisfied? Given $N=500.$