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/*
* Tacho.c
*
* Created: 19.06.2014 15:33:40
* Author: Jonas
*/
#define F_CPU 1000000
#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>
#define _PRIM PORTC
#define _SEC PORTD
#define _WHEEL_SIZE 207
//Define characters (negative)
#define _C1 0b10101111//0b01010000
#define _C2 0b11001000//0b00110111
#define _C3 0b10101000//0b00000000
#define _C4 0b10100101//0b00000000
#define _C5 0b10110000//0b00000000
#define _C6 0b10010001//0b00000000
#define _C7 0b10101110//0b00000000
#define _C8 0b10000000//0b00000000
#define _C9 0b10100000//0b00000000
#define _C0 0b10000010//0b00000000
#define _C_ 0b11111101
#define _CCLEAR 255
uint32_t cntr;
unsigned int speed;
ISR(TIMER0_OVF_vect)
{
cntr++;
}
inline void calcSpeed(void)
{
float tmrSpeed = F_CPU / 256;
float tmrTime = 1 / tmrSpeed;
float comTime = tmrTime * cntr;
float mps = (_WHEEL_SIZE / 100) / comTime;
float kmph = mps * 3.6;
speed = (int)kmph;
}//calcSpeed()
inline void render(int _screen)
{
char cNr[16];
int i1, i2;
itoa(_screen, cNr, 10); //convert int to string for rendering
if(_screen < 10)
{
i1 = 0;
i2 = 1;
cNr[1] = '0';
}
else
{
i1 = 1;
i2 = 0;
}
if(_screen > 99 || _screen < 0)
{
_SEC = _PRIM = _C_;
}
else
{
switch (cNr[i1]) //first character
{
case '0':
_PRIM = _C0;
PORTB &= ~(1<<PB2);
break;
case '1':
_PRIM = _C1;
PORTB &= ~(1<<PB2);
break;
case '2':
_PRIM = _C2;
PORTB |= (1<<PB2);
break;
case '3':
_PRIM = _C3;
PORTB &= ~(1<<PB2);
break;
case '4':
_PRIM = _C4;
PORTB &= ~(1<<PB2);
break;
case '5':
_PRIM = _C5;
PORTB &= ~(1<<PB2);
break;
case '6':
_PRIM = _C6;
PORTB &= ~(1<<PB2);
break;
case '7':
_PRIM = _C7;
PORTB &= ~(1<<PB2);
break;
case '8':
_PRIM = _C8;
PORTB &= ~(1<<PB2);
break;
case '9':
_PRIM = _C9;
PORTB &= ~(1<<PB2);
break;
}
switch (cNr[i2])//second character
{
case '0':
_SEC = _C0;
break;
case '1':
_SEC = _C1;
break;
case '2':
_SEC = _C2;
break;
case '3':
_SEC = _C3;
break;
case '4':
_SEC = _C4;
break;
case '5':
_SEC = _C5;
break;
case '6':
_SEC = _C6;
break;
case '7':
_SEC = _C7;
break;
case '8':
_SEC = _C8;
break;
case '9':
_SEC = _C9;
break;
}
}
}//render()
int main(void)
{
TCCR0 = (1 << CS00); // Prescaler 1
TIMSK = (1<<TOIE0); //Enable Overflowinterrupt
cntr = 0; //counter for Timer
DDRC = DDRD = 255; // Output for scrren pins
DDRB |= (1<<PB2);
DDRB &= ~(1<<PB1);
sei();
render(0);
//PORTC = 0b01010000;
while(1)//main loop
{
while(PINB & (1 << PB1) && cntr < 30000){} // wait for reed
TCCR0 = ~(1 << CS00); //disable counter
cli(); //disable interrupts
calcSpeed();
//reset all variables
cntr = 0;
TCNT0 = 0;
sei();//enable interrupts
TCCR0 = (1 << CS00); //enable counter
render(speed);//render the calculated speed
_delay_ms(100);
}
}//main()
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