Embedded Systems Design with the Atmel AVR Microcontroller Part II

168 CHAPTER 6. TIMING SUBSYSTEM
//6.2% = 2 ms = 180 degrees = 16 counts
//initiate PWM duty cycle variables
PWM_duty_cycle = 12;
OCR1BH = 0x00;
OCR1BL = (unsigned char)(PWM_duty_cycle);
//main activity loop - processor will continually cycle through loop for new
//activity. Activity initialized by external signals presented to PORTB[1:0]
while(1)
{
_StackCheck(); //check for stack overflow
read_new_input();
//read input status changes on PORTB
}
}//end main
//Function definitions
//*************************************************************************
//power_on_reset:
//*************************************************************************
void power_on_reset(void)
{
initialize_ports(); //initialize ports
}
//*************************************************************************
//initialize_ports: provides initial configuration for I/O ports
//*************************************************************************
void initialize_ports(void)
{
//PORTA
DDRA=0xff; //PORTA[7:0] output
PORTA=0x00; //Turn off pull ups