Getting Started

Chapter 7: Microcontroller Interrupts and Timers

set[j] = '\0';

arse_set number too large");

}

else

t));

}

ed[11];

unt,speed,10);

('\r');

milliSecInit(count);

*

/

// Sets the compare value
setOCR0A(count);

// Set PWM Phase Correct mode, CLK/8 prescaler

if(j>4)// must be < 256
{
sendString("Error - P
return 0;

{
set_speed(atoi(se

return 1;
}

void set_speed(int count)
{
char spe

sendString("Setting the Compare Timer Count to: ");
itoa(co
sendString(speed);
sendChar

}

/
The USART init set the system oscillator to 2 mHz. We set the
Timer0 prescaler
to clk/8 which gives a 250 kHz input to the timer/counter. A
compare of 250 throws
an interrupt every millisecond.

• void milliSecInit(unsigned char count)
  {
  // Enable timer0 compare interrupt
  TIMSK0 = (1<<OCIE0A);