Getting Started

Chapter 7: Microcontroller Interrupts and Timers

temp Register,

CCAL

r runs to fast, decrease OSCCAL

therwise, if temp is less than 6120, increment OSCCAL.

)

llator runs to slow, increase OSCCAL

}

; // the interRC is correct

timer:

CR1B = (1<<CS10); // start timer1

ow if you are beginning to think all this is mighty confusing, you are finally

understand the core truth of microcontroller programming. It IS

bug infested and time consuming and ego

estroying and... well, you name it. But finally getting something working is the

u don’t actually get some

leasure from working out these puzzles you don’t need to be doing this for a

areer. Try professional knife fighting... you’ll survive longer. This complexity is

rimary reason to ‘reuse’ code. And speaking of stealing them naked, the

llowing project uses code lifted directly from the WinAVR port of the ATMEL

utterfly code.

temp += tempL;
}

Is greater than 6250? If so decrement the Oscillator Calibration
OS

if (temp > 6250)

{

OSCCAL--;//RC oscillato

}

O

else if (temp < 6120
{
OSCCAL++; //RC osci

If temp is between 6250 and 6120 the calibration is complete and we can go
home.

else
calibrate = TRUE

But before we turn out the light, we start the

TC

N
beginning to
mighty confusing. And frustrating and
d
greatest pleasure known to mankind, (if you overlook sex, eating, parenting, and
anything else you like to do). A word of advice: if yo
p
c
p
fo
B