INTRODUCTION:

In this week's tutorial you will partially implement a reaction$-$time

game which will be controlled by the four pushbuttons on the QUTy.

The program randomly produces one of four values which correspond to a

unique output from both the buzzer and $7-$segment display.

These outputs are described in the table below:

VALUE $|$ Buzzer frequency $|7-$segment display

$------|------------------|------------------$

$0|4$XY $*2^(-5/12)|$ Segments EF $($LHS$)$

$1|4$XY $*2^(-8/12)|$ Segments BC $($LHS$)$

$2|4$XY $|$ Segments EF $($RHS$)$

$3|4$XY $*2^(-17/12)|$ Segments BC $($RHS$)$

where XY are the last two digits of your student number.

The aim of this game is for the player to press the pushbutton

corresponding to these outputs, as quickly as possible.

To indicate that a pushbutton has been pressed by the player, the same

outputs will be produced.

$*/$

void state$\_$machine$($void$)$;

int main$($void$)$

$\{$

$/**$ EX: $11\mathrm{.}0$

TASK: Implement the following functions:

$-$ "buzzer$\_$on$"$ and "buzzer$\_$off" in "buzzer.c$".$

$-$ "update$\_$playback$\_$delay" in "timer.c$".$

$*/$

cli$()$;

adc$\_$init$()$;

button$\_$init$()$;

spi$\_$init$()$;

pwm$\_$init$()$;

timer$\_$init$()$;

sei$()$;

state$\_$machine$()$;

$\}$

void enable$\_$outputs$($uint$8\_$t value$)$

$/**$ EX: $11\mathrm{.}0\mathrm{.}1$

TASK: Implement the functions below to turn the buzzer ON and OFF.

The "buzzer$\_$on$"$ function should take a single argument, "tone", which

ranges from $0$ to $3,$ and sets the frequency of the waveform output

generated by TCA$0$ correspondingly.

Ensure that the above macros reflect the four frequencies produced by

your program, given that TCA$0$ uses a DIV$2$ prescaler.

$*/$

void buzzer$\_$on$($const uint$8\_$t tone$)$

$\{$

static const uint$16\_$t base$\_$periods$[4]=\{$TONE$1\_$PER, TONE$2\_$PER, TONE$3\_$PER, TONE$4\_$PER$\}$;

$/**$ CODE: Write your code for Ex $11\mathrm{.}0\mathrm{.}1$ within this function. $*/$

uint$16\_$t playback$\_$delay $=100$;

void update$\_$playback$\_$delay$($void$)$

$\{$

$/**$ EX: $11\mathrm{.}0\mathrm{.}2$

To control the difficulty of this game, the player can use the

potentiometer to adjust the duration of the outputs produced by the

program.

TASK: Use ADC$0$ to update the "playback$\_$delay" variable based on the

position of the potentiometer. This value should be a linear

interpolation of the position of the potentiometer, ranging between

$100$ ms and $500$ ms$.$

In "initialisation.c:adc$\_$init", free$-$running mode has been disabled

to improve program efficiency and reduce sampling inconsistency.

Due to this, we must manually start conversions when this function

is called and wait for them to complete.

Use the following steps to achieve this:

$1.$ Start a conversion using the START group configuration in the

COMMAND register.

$2.$ Wait for a conversion to complete before updating the playback

delay. See the Result Ready flag in the INTFLAGS register.

$3.$ Upon reading the conversion result from the RESULT register,

clear the appropriate flag in the INTFLAGS register.

$*/$

$/**$ CODE: Write your code for Ex $11\mathrm{.}0\mathrm{.}2$ within this function. $*/$

$\}$

$/**$ EX: $11\mathrm{.}1\mathrm{.}1$

To promote modularity, we can write a function that enables the

$7-$segment display and buzzer. The pattern and tone should correspond

to either the random number generated by the program, or the input

provided by the player.

TASK: Use the functions "update$\_$display" and "buzzer$\_$on$"$ to enable

the outputs of the game based on the value passed to this function.

The outputs produced by this function should correspond to the table

above.

NOTE: Several macros have been defined in "display$\_$macros.h$"$ to be

used as inputs to the "update$\_$display" function.

To ensure timing is correct and fair, update the playback delay

after all outputs have been enabled, and then reset the

"elapsed$\_$time" variable.

$*/$

$/**$ CODE: Write your code for Ex $11\mathrm{.}1\mathrm{.}1$ within this function. $*/$

$\}$

void disable$\_$outputs$($void$)/**$

EX: $11\mathrm{.}1\mathrm{.}2$

TASK: Use the functions "update$\_$display" and "buzzer$\_$off" to disable

the $7-$segment display and buzzer.

$*/$

$/**$ CODE: Write your code for Ex $11\mathrm{.}1\mathrm{.}2$ within this function. $*/$

$\}$

typedef enum

$\{$

GENERATE,

PROMPT,

INPUT$\_$WAITING,

INPUT$\_$RECEIVED,

INPUT$\_$EVALUATE,

DISPLAY$\_$SUCCESS,

DISPLAY$\_$FAILURE

$\}$ state$\_$t;

void state$\_$machine$($void$)$

$\{$

disable$\_$outputs$()$;

$/**$ EX: $11\mathrm{.}2$

TASK: In the global scope we have declared an enumerated type $($enum$)$

that holds the values of each state required to implement the state

machine in state$\_$machine$\_$tut$11.$png$.$ Declare and initialise a

variable of this type to store the initial state of the state

machine.

$*/$

$/**$ CODE: Write your code for Ex $11\mathrm{.}2$ above this line. $*/$

$/**$ EX: $11\mathrm{.}3$

A pseudo$-$random number generator $($PRNG$)$ has been implemented in

"tut$11\_12.$o$",$ which is linked to this program. The function $"$rng$"$

can be called to generate a $32-$bit pseudo$-$random number.

TASK: Initialise a variable called "seed" with a value equal to your

student number in hexadecimal. Then, initialise the PRNG by calling

the "set$\_$seed" function.

$*/$

$/**$ CODE: Write your code for Ex $11\mathrm{.}3$ above this line. $*/$