/* timer2_init()
* Timer 2 is an 8-bit timer that can be operated asynchronously. I'll
* use it clocked by the 32.768 kHz crystal on the butterfly.
* In CTC mode, the OC2A pin will toggle when the timer reaches the
* compare register value. The pin has to toggle twice to reach
* its original state, so the square wave frequency at OC2A will be
* 32.768kHz / (2 * OCR2A) with no prescaler. */
void timer2_init(void) {
/* The recommended procedure for switching to an asychronous clock
* source:
* 1. Disable interrupts from timer 2 compare match and overflow */
TIMSK2 = 0;
/* 2. Set timer 2 to be clocked from the TOSC1 pin */
ASSR = (1<<AS2);
/* 3a. Set timer 2 prescaler. No prescaler is 001. */
TCCR2A = (0<<CS22) | (0<<CS21) | (1<<CS20);
/* 3b. Set Clear on Timer match mode */
TCCR2A |= (1<<WGM21) | (0<<WGM20);
/* 3c. Set the OC2A pin to toggle on compare match */
TCCR2A |= (0<<COM2A1) | (1<<COM2A0);
/* 4. Set timer 2's output compare register */
OCR2A = 33;
/* 5. Set the initial counter register value */
TCNT2 = 0;
/* 6. Look at the asynchronous status register to figure out if
* timer 2 has settled in to normal operation. This means that
* the counter value is being automatically updated (TCN2UB = 0),
* the configuration register is ready to take new values,
* (TCR2UB = 0), and that the output compare register is ready
* to take new values (OCR2UB = 0). */
while((ASSR & 1<<TCN2UB) | (ASSR & 1<<TCR2UB) | (ASSR & 1<<OCR2UB));
/* 7. Clear timer 2 interrupt flags */
TIFR2 = 0;
/* 8. Enable output compare match interrupt if necessary using:
* TIMSK2 = 1 << OCIE2A */
timer2_stop(); // Stop the counter
TCNT2 = 0; // Reset the counter
}
/// Blocks for a specified number of milliseconds
void wait_ms(unsigned int time_val) {
//Seting OC value for time requested
OCR2=250; //Clock is 16 MHz. At a prescaler of 64, 250 timer ticks = 1ms.
timer2_tick=0;
timer2_start(0);
//Waiting for time
while(timer2_tick < time_val);
timer2_stop();
}
__interrupt void timer2_overflow()
{
TIM2_SR1&=~0X01;//clear UIF bit
if(cnt_dir)
{
if(timecnt2++ == 2)
uart_state=UART_OVER;
else
return;
}
else if(--timeout2)
return;
timer2_stop();
}
inline void sendData(bool askforStatus,RF24 & radio){
reportBuffer.reportid=askforStatus?1:0;
bool ok = radio.write( &reportBuffer, sizeof(report_t) );
if (ok){
//status led off
PORTD &= ~(1<<LED1);
}
else{
//status led on
PORTD |= (1<<LED1);
#ifdef DEBUG
print_string("pa error\n");
#endif
radio.startListening();
radio.stopListening();
return;
}
radio.startListening();
if (askforStatus){
// Wait here until we get a response, or timeout (250ms)
bool timeout = false;
timer2_start();
while ( ! radio.available() && ! timeout ){
if (timer2_gettick() > 200 )
timeout = true;
}
// Describe the results
if ( timeout )
{
//status led on
PORTD |= (1<<LED1);
#ifdef DEBUG
print_string("Failed, response timed out.\n\r");
#endif
}
else
{
uint8_t response;
radio.read( &response, sizeof(uint8_t) );
//status led off
PORTD &= ~(1<<LED1);
if (response){
//battery led on
#ifdef DEBUG
print_string("led on\n");
#endif
PORTD |= (1<<LED2);
}else{
//battery led off
PORTD &= ~(1<<LED2);
#ifdef DEBUG
print_string("led off\n");
#endif
}
}
timer2_stop();
}
radio.stopListening();
}
