Lab 5: Synchronous State Machines - Reflex Timer Game

#include <avr/io.h>

#include <avr/interrupt.h>

const unsigned int ONE_MS = 4;

const unsigned int RT_Period = 1000;

unsigned int RT_Clk = 0;

unsigned int RT_Counter = 0;

enum RT_States { INIT, S0, S1 } RT_State;

//Interrupt service routine

//We enter this function ~4 times per millisecond,

//we can set a flag that signals a period has passed every period*4 times the function is entered.

//If our period is 1000 ms, then we would enter the function 1000*4 = 4000 times before transitioning to next state.

ISR(TIMER0_OVF_vect) { //Timer0 overflow interrupt service routine

       //Put code in me!

       //Count up to period and set flag

}

void RT_ClkTick() {

      //Put code in me!

       //wait until ISR sets flag

}

void RT_Tick() {

      switch(RT_State) { //transitions

      case INIT:

             //...

      }

      switch(RT_State) { //actions

      case S0:

             //...

      }

}

//Configure ATMega32 Timer0 control registers.  Correct values can be found in ATMega32 datasheet.

void InitTimer() {

      // Set prescaler to 8.  Since the ATMega32 runs at 8Mhz, our timer clock will run at 8MHz/8 = 1MHz.

      //TCCR0 |= ?

      //Enable Overflow Interrupt Enable on Timer0. 

      //TIMSK |= ?

      //Initialize starting value of timer

      TCNT0=0;

}

int main()

{

      DDRA = 0xFF;

      //Enable Global Interrupts

      SREG |= (1<<7);

      InitTimer();

      //init state

      RT_State = S0;

      //init output

      PORTA = 0x00;

      while(1) {

             RT_Tick();

            RT_ClkTick();

      }

}