add sound-reactive mode and pattern-cycling interrupt

1 files changed, 51 insertions, 0 deletions

diff --git a/eq.c b/eq.c
new file mode 100644
index 0000000..eb7febd
--- /dev/null
+++ b/eq.c
@@ -0,0 +1,51 @@
+#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 * 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() {
+	reset();
+
+	for (int i = 0; i < 7; ++i) {
+		strobe();
+	}
+}