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#include <avr/io.h>
#include <avr/interrupt.h>
#include "controller.h"
#include "bridge.h"
static void adc_init(void)
{
/* Configure the ADC */
ADMUX = (1 << REFS1) | (1 << REFS0);
/* select channel x (0 for now) */
ADMUX |= 0x0;
ADCSRA = (1 << ADEN) | (1 << ADIE)
| (1 << ADPS2) | (1 << ADPS1)
| (1 << ADPS0);
}
/* Initializes TIMER1 */
static void timer_init(void)
{
TCCR1B = (1 << WGM12) | (1 << CS12) | (1 << CS10);
OCR1A = 7200;
TIMSK|=(1<<OCIE1A);
}
static volatile char controller_in_init;
static volatile char controller_active;
static volatile long controller_target_temp;
static volatile char controller_num_iterations;
static volatile uint16_t controller_measured_temp;
void controller_init(void)
{
controller_active = 0;
controller_in_init = 1;
bridge_init();
adc_init();
timer_init();
}
int controller_set(long target)
{
if (target < 50 || target > 974)
return 1;
controller_target_temp = target;
controller_num_iterations = 1;
controller_active = 1;
return 0;
}
long controller_get(void)
{
return controller_measured_temp;
}
void controller_off(void)
{
controller_active = 0;
bridge_off();
}
ISR(TIMER1_COMPA_vect)
{
/* Start adc measurement */
ADCSRA |= (1<<ADSC);
}
ISR(ADC_vect)
{
if (controller_in_init) {
controller_measured_temp = ADCW;
controller_in_init = 0;
} else {
controller_measured_temp = (0.8 * controller_measured_temp)
+ (0.2 * ADCW);
}
if (! controller_active)
return;
controller_num_iterations--;
if (controller_num_iterations)
return;
controller_num_iterations = 60;
if ((long)controller_measured_temp < controller_target_temp - 5) {
/* Cooling required */
bridge_on_cool();
return;
}
if ((long)controller_measured_temp > controller_target_temp + 20) {
/* Heating required */
bridge_on_heat();
return;
}
/* Temperature is roughly okay, turn bridge off until next
* measurement. */
bridge_off();
}
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