Assignment #$10$ Due: May $3,2024$

This is a required homework. It also has some extra credits. Please upload your homework

solutions to Canvas. You need to upload your $.$asm file and a single pdf file containing your

screenshots.

$50$ pts $+50$ pts Extra Credit

In order to get the extra credit, your code should be working properly, and you need to upload both your

asm code and the pdf containing the screenshots.

In this assignment, we will use MPLabX to develop and simulate an assembly language program for the

PIC microcontroller that plays the guessing game, as described in Section $12\mathrm{.}7$ of the Wakerly textbook,

$5$th ed$.$ The assembly language program is to be tested using MPLab to apply the sequence of inputs

given below. The state diagram for this homework is modified such that there is a WIN output connected

to a green light showing that the guess was right $($WIN is asserted in the SOK state and the green light

turns on if the guess was correct$).$

This state machine has $4$ inputs and $6$ outputs. Students should use the PIC$16$F$84$A$.$ The required pin

assignments are given in the following table.

Required Pin Assignments

Inputs Right Outputs

Function PIC Function PIC

G$1$ RA$0$ L$1$ RB$0$

G$2$ RA$1$ L$2$ RB$1$

G$3$ RA$2$ L$3$ RB$2$

G$4$ RA$3$ L$4$ RB$3$

ERR RB$4$

WIN RB$5$

A high output is used to turn on a light while a low output signifies that the light is off.

Programs should initialize to state S$1$ and include a delay of ~$1\mathrm{.}0$ second from one state to the next in the

rotating light pattern. This delay could be created in different ways, for example, using a simple program

loop, or using a timer with or without interrupts. It need not be precise, but should be accurate to $\backslash$pm $0\mathrm{.}05$

seconds. You may choose your processor clock frequency to adjust the state delay.

The program should be tested using a stimulus workbook $($guessing$\_$game$\_$stimuli$\_$Spring$2024.$sbs$)$

that has been posted on Canvas with this assignment. This external stimulus is applied using

Stimulus $$ open a stimulus workbook $($from icons to the left of the Stimulus window$)$

being sure to $$Apply$$ the stimulus before you start debugging your code.

Your solution to this homework should include your documented assembly language code and watch

window to demonstrate that your game responds properly to stimulus. This example shows a watch

window following the first wrong guess. Your solution should show this watch window following each state

change. This can be done most easily by setting breakpoints immediately following each state change in

your code, then running the processor, which will automatically stop at each state change. You need to

use a processor frequency of $100$kHz $($instruction frequency Fcyc $=25$ kHz$).$

Sample Display window following the first correct guess

Hints and Suggested Approach

Computation of the next state could potentially follow the approach used in the textbook which is geared

for implementation using Verilog and logic hardware. There are other approaches, however, which are

more sensible for a byte oriented, general purpose machine such as the PIC. For example, the state

could be $$one$-$hot encoded$$ to match the outputs, and the next$-$state could be computed using the table

look$-$up or by if$-$then statements that consider the present state and the inputs.