Microcontroller Systems. ELET 3232 Topic 8: Slot Machine Example

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ELET 3232

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

We will work through a complete example



Use CodeVision and AVR Studio



Discuss a few ‘creative’ instructions



Discuss #define and #include



Read and write from/to ports



Use some of the control statements learned in

the last topic

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3 #include <Mega8515.h> /* processor specific information */

#define xtal 4000000L /* quartz crystal frequency [Hz] */ #define baud 9600 /* Baud rate */

#include <stdio.h> /* this gets the printf() definition */ // Global Variable Declarations..

char first,second,third; // Columns in the slot machine. char seed; // Number to form a seed for random #s. char count; // General purpose counter.

int delay; // A variable for delay time. void main(void) {

PORTA = 0xFF; // Initialize the I/O ports DDRA = 0x00; // port A all inputs

DDRB = 0x02; // port B.1 is an output (light) //Initialize the UART control register

//RX & TX enabled, 8 data bits UCSRB=0x18;

// initialize the UART's baud rate UBRRL=xtal/16/baud-1;

third ^= seed>>3;

seed++; // keep rolling over the seed pattern } while(PINA.0 == 0); // while the button is pressed for(count = 0; count < 5; count++) { // flash light when done..

for(delay = 0; delay < 10000; delay++) ; // just count up and wait PORTB.1 = 0; // turn the LED on.. for(delay = 0; delay < 10000; delay++)

;

PORTB.1 = 1; // turn the LED off.. }

first &= 3; // limit number to values from 0 to 3 second &= 3;

third &= 3;

printf("--> %d, %d ,%d <--\n",first, second, third); // show the values.. // determine a payout..

if((first == 3) && (second == 3) && (third == 3)) printf("Paid out: JACKPOT!!\n"); // all "cherries" else if((first == 3) || (second == 3) || (third == 3))

printf("Paid out: One Dime\n"); // if any are "cherries".. else if((first == second) && (second == third))

printf("Paid out: One Nickle\n"); // if three are alike, of any kind.. else

printf("Paid out: ZERO\n"); // otherwise -- you lose.. }

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Initialization

4

//

Phase 1..

#include <Mega8515.h>

/* processor specific information */

#define xtal 4000000L

/* quartz crystal frequency [Hz] */

#define baud 9600

/* Baud rate */

#include <stdio.h>

/* this gets the printf() definition */

// Global Variable Declarations..

char first,second,third;

// Columns in the slot machine.

char seed;

// Number to form a seed for random #s.

char count;

// General purpose counter.

int delay;

// A variable for delay time.

void main(void) {

PORTA = 0xFF;

// Initialize the I/O ports

DDRA = 0x00;

// port A all inputs

DDRB = 0x02;

// port B.1 is an output (light)

//Initialize the UART control register

//RX & TX enabled, 8 data bits

UCSRB=0x18;

// initialize the UART's baud rate

UBRRL=xtal/16/baud-1;

The #include commands instruct

the compiler to include these files

as part of the overall program

when compiling

The Mega8515.h file includes all

of the definitions for labels as

well as port addresses.

The stdio.h file includes

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5

#define baud 9600

/* Baud rate */

#include <stdio.h>

/* this gets the printf() definition */

// Global Variable Declarations..

char first,second,third;

// Columns in the slot machine.

char seed;

// Number to form a seed for random #s.

char count;

// General purpose counter.

int delay;

// A variable for delay time.

void main(void) {

PORTA = 0xFF;

// Initialize the I/O ports

DDRA = 0x00;

// port A all inputs

DDRB = 0x02;

// port B.1 is an output (light)

//Initialize the UART control register

//RX & TX enabled, 8 data bits

UCSRB=0x18;

// initialize the UART's baud rate

UBRRL=xtal/16/baud-1;

For the Atmega128, we have to

change this to Mega128 – but, the

Atmega128 does not have the

UART initialized below

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Initialization

6

//

Phase 1..

#include <Mega8515.h>

/* processor specific information */

#define xtal 4000000L

/* quartz crystal frequency [Hz] */

#define baud 9600

/* Baud rate */

#include <stdio.h>

/* this gets the printf() definition */

// Global Variable Declarations..

char first,second,third;

// Columns in the slot machine.

char seed;

// Number to form a seed for random #s.

char count;

// General purpose counter.

int delay;

// A variable for delay time.

void main(void) {

PORTA = 0xFF;

// Initialize the I/O ports

DDRA = 0x00;

// port A all inputs

DDRB = 0x02;

// port B.1 is an output (light)

//Initialize the UART control register

//RX & TX enabled, 8 data bits

UCSRB=0x18;

// initialize the UART's baud rate

UBRRL=xtal/16/baud-1;

For the Atmega128, we have to

change this to Mega128 – but, the

Atmega128 does not have the

UART initialized below

They will generate errors for the

128

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7

#define baud 9600

/* Baud rate */

#include <stdio.h>

/* this gets the printf() definition */

// Global Variable Declarations..

char first,second,third;

// Columns in the slot machine.

char seed;

// Number to form a seed for random #s.

char count;

// General purpose counter.

int delay;

// A variable for delay time.

void main(void) {

PORTA = 0xFF;

// Initialize the I/O ports

DDRA = 0x00;

// port A all inputs

DDRB = 0x02;

// port B.1 is an output (light)

//Initialize the UART control register

//RX & TX enabled, 8 data bits

UCSRB=0x18;

// initialize the UART's baud rate

UBRRL=

xtal

/16/

baud

-1;

The #define commands instructs

the compiler to equate these

values with the labels “baud” and

“xtal”. They are used in the

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Initialization

8

//

Phase 1..

#include <Mega8515.h>

/* processor specific information */

#define xtal 4000000L

/* quartz crystal frequency [Hz] */

#define baud 9600

/* Baud rate */

#include <stdio.h>

/* this gets the printf() definition */

// Global Variable Declarations..

char first,second,third;

// Columns in the slot machine.

char seed;

// Number to form a seed for random #s.

char count;

// General purpose counter.

int delay;

// A variable for delay time.

void main(void) {

PORTA = 0xFF;

// Initialize the I/O ports

DDRA = 0x00;

// port A all inputs

DDRB = 0x02;

// port B.1 is an output (light)

//Initialize the UART control register

//RX & TX enabled, 8 data bits

UCSRB=0x18;

// initialize the UART's baud rate

UBRRL=xtal/16/baud-1;

These variables are global

because they are declared outside

the main() function

first, second, third, seed, and

count are declared as

char

(8-bit

unsigned integers).

delay is declared as an

int

, a

16-bit unsigned integer

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9

#define baud 9600

/* Baud rate */

#include <stdio.h>

/* this gets the printf() definition */

// Global Variable Declarations..

char first,second,third;

// Columns in the slot machine.

char seed;

// Number to form a seed for random #s.

char count;

// General purpose counter.

int delay;

// A variable for delay time.

void

main(

void

) {

PORTA = 0xFF;

// Initialize the I/O ports

DDRA = 0x00;

// port A all inputs

DDRB = 0x02;

// port B.1 is an output (light)

//Initialize the UART control register

//RX & TX enabled, 8 data bits

UCSRB=0x18;

// initialize the UART's baud rate

UBRRL=xtal/16/baud-1;

This program has one function:

main(). It:

Accepts no inputs

and

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Initialization

10

//

Phase 1..

#include <Mega8515.h>

/* processor specific information */

#define xtal 4000000L

/* quartz crystal frequency [Hz] */

#define baud 9600

/* Baud rate */

#include <stdio.h>

/* this gets the printf() definition */

// Global Variable Declarations..

char first,second,third;

// Columns in the slot machine.

char seed;

// Number to form a seed for random #s.

char count;

// General purpose counter.

int delay;

// A variable for delay time.

void main(void) {

PORTA = 0xFF;

// Initialize the I/O ports

DDRA = 0x00;

// port A all inputs

DDRB = 0x02;

// port B.1 is an output (light)

//Initialize the UART control register

//RX & TX enabled, 8 data bits

UCSRB=0x18;

// initialize the UART's baud rate

UBRRL=xtal/16/baud-1;

It first initializes Port A and Port

B

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11

#define baud 9600

/* Baud rate */

#include <stdio.h>

/* this gets the printf() definition */

// Global Variable Declarations..

char first,second,third;

// Columns in the slot machine.

char seed;

// Number to form a seed for random #s.

char count;

// General purpose counter.

int delay;

// A variable for delay time.

void main(void) {

PORTA = 0xFF;

// Initialize the I/O ports

DDRA = 0x00;

// port A all inputs

DDRB = 0x02;

// port B.1 is an output (light)

//Initialize the UART control register

//RX & TX enabled, 8 data bits

UCSRB=0x18;

// initialize the UART's baud rate

UBRRL=xtal/16/baud-1;

It first initializes Port A and Port

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Main Program

12

The main program is contained in

the

while (1) { }

loop structure: it

mean run forever

first = second = third = seed; // preload the columns do { // mix up the numbers

// while waiting for button release. first ^= seed>>1; // Exclusive ORing in the moving seed second^= seed>>2; // can really stir up the numbers. third ^= seed>>3;

seed++; // keep rolling over the seed pattern } while (PINA.0 == 0); // while the button is pressed

for (count = 0; count < 5; count++) { // flash light when done.. for (delay = 0; delay < 10000; delay++)

; // just count up and wait PORTB.1 = 0; // turn the LED on..

for (delay = 0; delay < 10000; delay++) ;

third &= 3;

printf("Paid out: ZERO\n"); // otherwise -- you lose..

}

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13

The main program is contained in

the

while (1) { }

loop structure: it

mean run forever

first ^= seed>>1; // Exclusive ORing in the moving seed second^= seed>>2; // can really stir up the numbers. third ^= seed>>3;

third &= 3;

}

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Main Program

14

This

while loop

is made up of

these two instructions

third &= 3;

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15

This

while loop

is made up of

these two instructions. As long as

the button is not pushed

(connected to bit 0 of Port A),

PINA.0 will be 1 (or TRUE) and

seed will be incremented.

third &= 3;

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Main Program

16

When the button is pushed, the

program will execute this

assignment statement…….

third &= 3;

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17

Then the for loops are executed

to blink the LED.

PORTB.1 =0, instructs the

program to make pin 1 of

PORTB low, turning the LED on.

PORTB.1 =1, instructs the

program to make pin 1 of

PORTB high, turning the LED

off.

for (count = 0; count < 5; count++) { // flash light when done..

for (delay = 0; delay < 10000; delay++)

; // just count up and wait

PORTB.1 = 0; // turn the LED on..

PORTB.1 = 1; // turn the LED off..

}

third &= 3;

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Main Program

18

The program then ANDS each of

the variables with the constant

“3”. It ensures that the variables

have to be between 0 and 3.

first &= 3; // limit number to values from 0 to 3

second &= 3; third &= 3;

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19

The remainder of this program

will have no effect because we

don’t have any output device

connected (or simulated)

third &= 3;

} }

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20



The program (Slot.c) was copied from the book



It can be compiled by CodeVision and

simulated with AVR Studio



It was typed in using WordPad



So, it must be loaded into a CodeVision project



The project must be created first



Typically the wizard would be used, but this time we

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

Normally, the most

recent project worked

on would be loaded



In this case, no project

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

Choose NEW from

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the File Menu



This dialog box will

open

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

Choose NEW from

the File Menu



This dialog box will

open



Choose project



You will be asked if

you want to use the

Wizard

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25

to do many things



Specify AVR



Specify Clock speed



Configure ports



Provide project

information



Define interrupts and

timers

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

We will choose NO

(this time) because

most of these

parameters have

been specified in the

source file

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

The Configure

Project Box appears



Click Add



Choose source file



(I had typed it in in

WordPad and

stored it in this

directory)

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Project Box appears



Click Add



The source file

appears as part of the

project

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

The Configure

Project Box appears



Click Add



The source file

appears as part of the

project



You may specify

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Project Box appears



You can specify many

parameters



AVR



Clock speed



Memory model



RAM size



etc…….

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

The source file

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appears



I assumed the file

was correct

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

The source file

appears



I assumed the file

was correct



Chose Build All



You’ll get

information about

your program

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35

appears



I assumed the file

was correct



Chose Build All



You’ll get

information about

your program



And the assembler

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

And click on the

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

Click OK



And click on the

debugger



AVR Studio is

called (to run its

simulator)

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40



Choose OPEN



And then choose

the *.cof file that

was created by

CodeVision

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

And then choose

the *.cof file that

was created by

CodeVision



Then AVR Studio

prompts you to

save its project file

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

Choose AVR and

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AVR Simulator



Click finish



The simulator

(debugger) starts

automatically

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

You’ll want to watch

the variables and

registers



(how else would

you know if your

program is

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

From the VIEW Menu

choose Watch



The watch window

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slots in the NAME

column



Type in the names

of the variables you

want to watch

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

You may also want to

watch the registers or

memory



Click on VIEW

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

You may also want to

view the ports



Click the + next to

I/O ATMEGA128



And then the + next

to PORTA and

PORTB

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points (variables will

not be updated will

running the program)

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program will run to the

1 st

_{break point}

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

Click RUN and the

program will run to the

1 st

_{break point}



The do/while loop will

continue as long as

PINA.0 =0

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the values have

changed for the

variables

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

A few iterations later,

the values have

changed for the

variables



Set PINA.0 and the

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test the output



For example:



Instead of printf () commands we could set

bits in PortB



Or declare a few other variables to set or

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