eq.c


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53

#include "config.h"
#include "eq.h"

#include <avr/io.h>
#include <util/delay.h>

unsigned char eq_levels[7];

static const unsigned char thresholds[][2] = { EQ_THRESHOLDS };

static void reset() {
	PORTB |= (1 << EQ_PIN_RESET);
	PORTB &= ~(1 << EQ_PIN_RESET);
	_delay_us(36);
}

static void strobe() {
	PORTB |= (1 << EQ_PIN_STROBE);
	_delay_us(36);
	PORTB &= ~(1 << EQ_PIN_STROBE);
	_delay_us(36);
}

static unsigned char map_level(unsigned char val, unsigned char min, unsigned char max) {
	if (val <= min)
		return 0;
	else if (val >= max)
		return 255;
	else
		return (val - min) * 255 / (max - min);
}

void eq_read() {
	reset();

	for (int i = 0; i < 7; ++i) {
		strobe();

		ADCSRA |= (1 << ADSC);
		while (ADCSRA & (1 << ADSC));
		eq_levels[i] = map_level(ADCH, thresholds[i][0], thresholds[i][1]);
	}
}

void eq_decay(int cycles) {
	for (int i = 0; i < cycles; ++i) {
		reset();

		for (int i = 0; i < 7; ++i) {
			strobe();
		}
	}
}