From a2dca81d7cac47cb4596ecca677354d357d3a62e Mon Sep 17 00:00:00 2001
From: twobit <twobit@lavabit.com>
Date: Mon, 6 Aug 2012 01:45:37 +0200
Subject: [PATCH] polyphonie

---
 firmware/main.c | 91 ++++++++++++++++++-------------------------------
 1 file changed, 34 insertions(+), 57 deletions(-)

diff --git a/firmware/main.c b/firmware/main.c
index c01582c..4932eca 100644
--- a/firmware/main.c
+++ b/firmware/main.c
@@ -24,15 +24,10 @@ typedef struct {
 
 typedef struct {
 	synth_channel_t channels[synth_channel_count];
-	uint16_t output;
 } synth_t;
 
 static synth_t synth;
 
-uint8_t counter = 0;
-uint8_t pulsewidth = 0;
-uint16_t maxcounter = 0xFF;
-uint16_t pulsecounter = 0;
 
 static void synth_init(void)
 {
@@ -44,49 +39,49 @@ static void synth_init(void)
 	synth.channels[1].speed = 1728;
 }
 
-static inline void synth_mix(void)
+static inline uint16_t synth_mix(void)
 {
-	synth.output = 0;
+	uint16_t output = 0;
 
 	for (int i = 0; i < synth_channel_count; i++) {
 		synth_channel_t *chan = &synth.channels[i];
 		chan->phase += chan->speed;
-
-		synth.output += (chan->phase >> 8) & 0xff;
+		output += ((chan->phase >> 8) & 0xff) / 2;
 	}
+
+	return output;
 }
 
 static void init_sampletimer(void)
 {
 	// Timer 0
-	//
-	//set timer0 to CTC & prescaler 64 == 125k
+	// set timer0 to CTC & prescaler 64 == 125k
 	TCCR0A = (1 << WGM01);
 	TCCR0B = (1 << CS00) | (1 << CS01);
-	//count up to 5 :
+	// count up to 5 :
 	OCR0A = 3;
-	TCNT0=0;
-	//enable interrupt
+	TCNT0 = 0;
+	// enable interrupt
 	TIMSK0 |=  (1<<OCIE0A);
 }
 
 static inline void init_pwm(void)
 {
-	//PB2 set to output:
+	// PB2 set to output:
 	DDRB |= (1 << PORTB2);
-	OCR1B = 0x001F;		//preselect some default
+	OCR1B = 0x001F;		// preselect some default
 	ICR1 = 0x00FF;		// TOP-wert
 
 	TCCR1A = (1 << COM1B1) | (1 << WGM11);	// only b-chan , fastpwm (mode 14)
-	TCCR1B = (1 << WGM13) | (1 << WGM12) | (1 << CS10);	//Fastpwm, no prescale
+	TCCR1B = (1 << WGM13) | (1 << WGM12) | (1 << CS10);	// Fastpwm, no prescale
 
-	//TIMSK1 |=  (1 << OCIE1B); //enable timer 1 Output compare
+	// TIMSK1 |=  (1 << OCIE1B); //enable timer 1 Output compare
 	return;
 }
 
 static void init_leds(void)
 {
-	//enable LED channels as output
+	// enable LED channels as output
 	DDRC |= (1 << PORTC0) | (1 << PORTC2) | (1 << PORTC3) | (1 << PORTC1);
 	PORTC = 1;		//one led is on...
 	return;
@@ -94,7 +89,7 @@ static void init_leds(void)
 
 inline void setleds(uint8_t state)
 {
-	//set leds according to
+	// set leds according to
 	PORTC |= (state | 0b00001111);
 	PORTC &= ~(state | 0b11110000);
 	return;
@@ -102,7 +97,7 @@ inline void setleds(uint8_t state)
 
 static void init_motor(void)
 {
-	//vibration motor on B1:
+	// vibration motor on B1:
 	DDRB |= (1 << PORTB1);
 
 }
@@ -113,69 +108,51 @@ static void init_motor(void)
 int main(void)
 {
 
-	//hardware initialisation:
+	// hardware initialisation:
 	init_leds();
-	//init_motor();
+	// init_motor();
 	init_pwm();
 	init_sampletimer();
-	//sample_pending = 0;
-	//synth_init();
-	//OCR1B = 0x00F0;
+
+	synth_init();
+	// OCR1B = 0x00F0;
 	sei();
 
+	while(1) {}
 
-	while(1){
-		//PORTC ^= 0b1;
-	}
-	while(1);
-	while(1) {
-		while (0 == sample_pending) ;
-		sample_pending = 0;
-		synth_mix();
-	}
-
-	//never get here
+	// never get here
 	return 0;
 }
 
-/*ISR(TIMER1_COMPB_vect)
-{
-   OCR1B = 0x00F0;	
-} */
 
-//25kHz
+// 25kHz
 ISR(TIMER0_COMPA_vect)
 {
+	// test stuff
+	/*
+	static uint16_t counter = 0;
+	static uint16_t pulsewidth = 0;
+	static uint16_t maxcounter = 0x133;
+	static uint16_t pulsecounter = 0;
 	counter++;
 	if (counter > maxcounter){
 	 	counter = 0;
 	};
- 	
 
 	pulsecounter++;
-	if (pulsecounter > 0x0200){
+	if (pulsecounter > 0x300){
 		 pulsecounter = 0;
 		 pulsewidth++;
 		 if (pulsewidth > maxcounter){
 			pulsewidth = 0;
 		}
 	}
+	OCR1B = ((counter > pulsewidth) ? 0xff : 0x00);
+	*/
 
 
-	
-	OCR1B = ((counter > pulsewidth) ? maxcounter : 0x00);
-	
+	OCR1B = synth_mix();
 
-	//OCR1B = counter;	
-	//OCR1B = OCR1B + 4;
-	if (OCR1B > 0x007F) {
-	//	OCR1B = 0x00F;
-	}	
-	PORTC ^= 0b01;
-
-	//ICR1 = synth.output;
-	//sample_pending = 1;
-	
 }