hbc: sensor based on back emf

- voltage divider for ~1.6V
- AIN0 and AIN1: AIN1 has LRA and checks if treshold is above 1.6

diff --git a/hbc.c b/hbc.c
index 6080410..c5c2c0d 100644 (file)
--- a/hbc.c
+++ b/hbc.c
@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <stdbool.h>
 #include <avr/io.h>
 #include <avr/wdt.h>
 #include <avr/sleep.h>
@@ -8,17 +9,17 @@
 #include <util/delay.h>
 #include "haptic.h"
        
-volatile int xvar = 1;
-
-/* idle mode will wake up board and will
- * return PC after latest sleep_mode() call */
-EMPTY_INTERRUPT(SIG_COMPARATOR);
-
-ISR(TIM0_COMPA_vect)
-{      
-       xvar++;
+ISR(SIG_COMPARATOR)
+{
+       if (ACSR & (1 << ACO)) {
+               PORTB |= (1 << PB4);
+       } else {
+               PORTB &= ~(1 << PB4);
+       }
 }
 
+EMPTY_INTERRUPT(TIM0_COMPA_vect);
+
 static void switch_idle(void)
 {
        sei();
@@ -35,33 +36,47 @@ static void init_board(void)
         * When the bandgap reference is connected to the Analog Comparator (by setting the ACBG bit in ACSR). */
 }
 
+static void set_ref_voltage(void)
+{
+       DDRB |= (1 << DDB1); /* set PB0 as output */
+       TCCR0A = TCCR0B = 0;
+       TCCR0A |= (1 << WGM01) | (1 << WGM00) | (1 << COM0B1);
+       TCCR0B |= (1 << CS00); /* clk/1024 prescaler */
+       OCR0B = 0x20; /* 25% duty cycle */
+       TCNT0 = 0;
+       TIMSK = (1 << OCIE0B); /* enable interrupts for overflow and compare */
+}
+
+static void config_comparator(void)
+{
+       ADCSRA = 0;
+       ADCSRB |= (1 << ACME); /* multiplex enable */
+       
+       //ADMUX |= (1 << MUX0); /* ADC1 as negative input */
+       
+       ACSR &= ~(1 << ACD); /* enable comparator */
+       //ACSR |= (1 << ACBG);
+       //ACSR |= (1 << ACIS1) | (1 << ACIS0);
+
+       DIDR0 |= (1 << AIN1D) | (1 << AIN0D);
+
+       ACSR |= (1 << ACIE); /* enable interrupts */
+}
+
 int main(void)
 {
        init_board();
-       xvar = 1;       
+
+       DDRB |= (1 << DDB4);
+       //PORTB |= (1 << PB1);
+
        cli();
-       DDRB |= (1 << DDB0); /* set PB0 as output */
-       TCCR0A = TCCR0B = 0;
-       TCCR0A |= (1 << WGM01) | (1 << WGM00) | (1 << COM0A1);
-       TCCR0B |= (1 << CS02) | (1 << CS00); /* clk/1024 prescaler */
-       OCR0A = 0x7F; /* 50% duty cycle */
-       TCNT0 = 0;
-       TIMSK = (1 << OCIE0A); /* enable interrupts for overflow and compare */
+       //set_ref_voltage();
+       config_comparator();
        sei();
 
        while(1) {
                _delay_ms(100);
-               /* set LRA as sensor and switch to idle mode
-                * check back-EMF of LRA: if treshold is surpassed
-                * comparator intterupt is triggered */
-//             set_lra_as_sensor();
-//             switch_idle(); 
-//
-//             /* board wakes up, set LRA as actuator and
-//              * plays haptic effect */
-//             set_lra_as_actuator();
-//             play_haptic();
-
        }
 
 }