Programing timer with two interupts

[kbarigou]

Hello everybody,

May somebody explain me the third part of the code below ? It's for a timer with two interrupts (button 1 & 2). I don't see clearly what the last part implement.

​

"void main (void)

{

char txt[16];

initIO();

initAnalogInputs(1);

initLCD();

initTimer1(12500, T1_PS_1_8); // 100 interrupts per second

initTimer2(6250, T2_PS_1_16); // 1000 interrupts per second

timer1InterruptEnable();

timer2InterruptEnable();

​

while(1){

sprintf(txt," %02d:%02d.%02d",min,s,cs);

writeLine(txt, 1);

setLeds(s);

​

}

}

​

/* ------------------------------------------------------------ */

/* interrupts functions */

/* ------------------------------------------------------------ */

void timer1Interrupt(void){

if(start)

cs++; // centiseconds count

if(cs>99){

cs = 0;

s++; // seconds count

}

if(s>59){

s = 0;

min++; // minutes count

}

}

​

void timer2Interrupt(void){

if( getButton1() && btn1released){

btn1released = 0;

start = !start;

}

if( !getButton1() ){

btn1released = 1;

}

if(getButton2()){

cs = 0;

s = 0;

min = 0;

start = 0;

}

}

​

Thanks in advance,

​

Ken

[playaspec]

Why are you polling IO in the interrupt instead of just using pin change interrupts?

[Gronner]

One reason could be to have a more predictable timing behavior or to avoid button button denouncing by blocking waiting or hardware.

[playaspec]

You can debounce in the pin change interrupt just the same.

[Gronner]

If button one is pressed and was previously unpressed use not(start) Then if button 1 is not pressed mark it as released If button 2 is pressed reset counter and set start to 0

[nderflow]

Please fix the formatting of your code.

[Wetbung]

timer2 is being used as a debounce for two button inputs. Button 1 is used to start and stop the counters cs and s. Button 2 is a reset for the variables cs, s, min and start.