Speedometer.c

/*****************************************************

Project : SPEEDOMETER

Version : 1.0                     

Comments: Peter Reinisch

Chip type           : ATmega8515

Program type        : Application

Clock frequency     : 8.000000 MHz 64MS

Memory model        : Small

External SRAM size  : 0

Data Stack size     : 128

Compiled with CodeVisionAVR C cross-compiler.

*****************************************************/

#include <mega8515.h>

// Alphanumeric LCD Module functions

#include <alcd.h>

// Standard library functions (itoa, ftoa etc.)

#include <stdlib.h>

// Delay functions

#include <delay.h> 

// Nicknames for port pins

#define PLUS_KEY PINC.0

#define MINUS_KEY PINC.1

#define ENTER_KEY PINC.2

#define DIA_KEY PINC.3

#define SPEED_PORT PORTC.7

// Nicknames for delays, Etc.

#define DEBOUNCE_DELAY 80

#define REFRESH_DELAY 200

#define SPEED_MULTIPLIER 292

#define PULSE_TURN 12

// Global variables

unsigned char circ=0;           // Calculated circumference

unsigned int dcm=0;             // Distance covered in cm (modul 100m)

unsigned long speed=0;          // Calculated speed

unsigned int trip=0;            // Trip distance (0.1 Km)

unsigned long distance=0;       // Total distance (0.1 Km)

unsigned char overflow=0;       // Timer1 overflow; for long delays

unsigned long count=0;          // Current Timer1 count

unsigned long lastcount=0;      // Last Timer1 count

// Some messages

flash char msg_saving[]="Saving Data...";

flash char msg_circ[]="Circumference:";

flash char msg_dia[]="Enter Circum";

flash char msg_cm[]=" cm";

// Temporary variables

char tempstr[10];

// EEPROM saved variables

// Note that these variables are not written periodically.

// The diameter is written only when the diameter is changed from the menu.

// The odometer reading is saved only when the main power to the system is cut-off.

eeprom unsigned long int save_odometer=0;

eeprom unsigned long int save_trip=0;

eeprom unsigned char save_circ=0;

eeprom unsigned long int save_dcm=0;

// Timer 0 overflow interrupt service routine

// Current speed of the vehicle if no input pulse

// arrives within the expected period.

interrupt [TIM0_OVF] void timer0_ovf_isr(void)

{

        count=overflow*65536+TCNT1;

        if(count>lastcount)

        {

                speed=(unsigned int) ((circ/PULSE_TURN)*SPEED_MULTIPLIER)/count;

        }   

}

// Timer 1 overflow interrupt service routine

interrupt [TIM1_OVF] void timer1_ovf_isr(void)

{

        overflow++;

}

// External Interrupt 0 service routine

// A pulse is recieved & this function gets called..

interrupt [EXT_INT0] void ext_int0_isr(void)

{

        // Increment dcm modul 10000 (0.1 Km)

        dcm=dcm+(circ/PULSE_TURN);

        if(dcm>10000)

        {

                dcm=dcm-10000;

                // For every 10000 cm, trip and distance are incremented by 1 (0.1 Km)

                trip++;

                distance++;

        }

        count=overflow*65536+TCNT1;

        lastcount=count;  // Save the current count (for automatic damping of speed by Timer0)

        // Reset the timer

        TCNT1=0;

        overflow=0;

        speed=(unsigned int)((circ/PULSE_TURN)*SPEED_MULTIPLIER)/count;

}

// External Interrupt 1 service routine

// This interrupt is triggered automatically only

// when the main power to the circuit is removed (turning off the vehicle).

interrupt [EXT_INT1] void ext_int1_isr(void)

{

        // Save odometer reading in EEPROM

        save_odometer=distance;

        save_trip=trip;

        save_dcm=dcm;

        lcd_clear();

        lcd_putsf(msg_saving);  // "Saving Data..."

        delay_ms(1000);

}

void main(void)

{

// Input/Output Ports initialization

// Port A initialization

PORTA=0x00;

DDRA=0x00;

// Port B initialization

PORTB=0x00;

DDRB=0x00;

// Port C initialization

PORTC=0x00;

DDRC=0x80;

// Port D initialization

PORTD=0x00;

DDRD=0x00;

// Port E initialization

PORTE=0x00;

DDRE=0x00;

// Timer/Counter 0 initialization

// Clock source: System Clock

// Clock value: 7.813 kHz

// Mode: Normal top=FFh

// OC0 output: Disconnected

TCCR0=0x05;

TCNT0=0x00;

OCR0=0x00;

// Timer/Counter 1 initialization

// Clock source: System Clock

// Clock value: 7.813 kHz

// Mode: Normal top=FFFFh

// OC1A output: Discon.

// OC1B output: Discon.

// Noise Canceler: Off

// Input Capture on Falling Edge

// Timer 1 Overflow Interrupt: On

// Input Capture Interrupt: Off

// Compare A Match Interrupt: Off

// Compare B Match Interrupt: Off

TCCR1A=0x00;

TCCR1B=0x05;

TCNT1H=0x00;

TCNT1L=0x00;

ICR1H=0x00;

ICR1L=0x00;

OCR1AH=0x00;

OCR1AL=0x00;

OCR1BH=0x00;

OCR1BL=0x00;

// External Interrupt(s) initialization

// INT0: On     ; Input Pulses

// INT0 Mode: Falling Edge

// INT1: On     ; Save the current odometer reading

// INT1 Mode: Falling Edge

// INT2: Off    ; Not used

GICR|=0xC0;

MCUCR=0x0A;

EMCUCR=0x00;

GIFR=0xC0;

// Timer(s)/Counter(s) Interrupt(s) initialization

TIMSK=0x82;

// Analog Comparator initialization

// Analog Comparator: Off

// Analog Comparator Input Capture by Timer/Counter 1: Off

ACSR=0x80;

// LCD module initialization

// Connections are specified in the

// Project|Configure|C Compiler|Libraries|Alphanumeric LCD menu:

// RS - PORTA Bit 0

// RD - PORTA Bit 2

// EN - PORTA Bit 1

// D4 - PORTA Bit 4

// D5 - PORTA Bit 5

// D6 - PORTA Bit 6

// D7 - PORTA Bit 7

// Characters/line: 16/2

lcd_init(16);

//Read saved odometer reading

distance=save_odometer;

trip=save_trip;

dcm=save_dcm;

//Read saved diameter

circ=save_circ;

lcd_putsf(msg_circ);            // "Circumference:"

itoa(circ, tempstr);

lcd_gotoxy(3,1);

lcd_puts(tempstr);

lcd_putsf(msg_cm);              // " cm"

delay_ms(1000);

// Global enable interrupts

#asm("sei")

while(1)

{

        lcd_clear();

        if(speed<1)

                speed=0;

        // Convert speed to string

        ftoa(speed, 0, tempstr);

        // Display it on the screen

        lcd_gotoxy(0,0);

        lcd_puts(tempstr);

        lcd_putsf("Km/h");

        // Convert trip distance (in Km) to string

        ftoa((float)trip/10, 1, tempstr);

        // Display it on the screen

        lcd_gotoxy(0,1);

        lcd_puts(tempstr);

        //lcd_putsf("Km");

        // Convert total distance (in Km) to string

        ftoa((float)distance/10, 1, tempstr);

        // Display it on the screen

        lcd_gotoxy(8,1);

        lcd_puts(tempstr);

        delay_ms(REFRESH_DELAY);

        // If the Trip Rest switch is pressed for more then 500ms, clear the trip meter

        if(ENTER_KEY==0)

        {

                delay_ms(500);

                if(ENTER_KEY==0)

                {

                        trip=0;

                }

        }

        // If the Change Diamter key is pressed for more than a second,

        if(DIA_KEY==0)

        {

                delay_ms(1000);

                if(DIA_KEY==0)

                {

                        while (1)

                        {

                                lcd_clear();

                                lcd_putsf(msg_dia);

                                itoa(circ,tempstr);

                                lcd_gotoxy(3,1);

                                lcd_puts(tempstr);

                                lcd_putsf(msg_cm);

                                if(PLUS_KEY==0 && circ<250)

                                {

                                        delay_ms(DEBOUNCE_DELAY);

                                        if(PLUS_KEY==0)

                                                circ=circ+1;

                                } else

                                if(MINUS_KEY==0 && circ>1)

                                {

                                        delay_ms(DEBOUNCE_DELAY);

                                        if(MINUS_KEY==0)

                                                circ=circ-1;

                                } else

                                if(ENTER_KEY==0)

                                {

                                        delay_ms(DEBOUNCE_DELAY);

                                        if(ENTER_KEY==0)

                                        {               

                                                lcd_clear();

                                                lcd_putsf(msg_circ);    // "Circumference:"

                                                itoa(circ, tempstr);

                                                lcd_gotoxy(3,1);

                                                lcd_puts(tempstr);

                                                lcd_putsf(msg_cm);      // " cm"

                                                // Save in EEPROM

                                                save_circ=circ;

                                                delay_ms(1000);

                                                break;

                                        }               

                                }      

                                else

                                        delay_ms(DEBOUNCE_DELAY);

                        };

                }

        }

};

}