From b1355d3cdba26fe18c5a69fc6d94c93478559788 Mon Sep 17 00:00:00 2001
From: "Jan \"Yenya\" Kasprzak" <kas@fi.muni.cz>
Date: Fri, 8 Jun 2012 19:17:30 +0200
Subject: [PATCH] ADC-driven PWM

---
 lights.c | 40 +++++++++++++++++++++++++++++++++-------
 1 file changed, 33 insertions(+), 7 deletions(-)

diff --git a/lights.c b/lights.c
index 49bf4ce..653e8d4 100644
--- a/lights.c
+++ b/lights.c
@@ -1,29 +1,55 @@
 #include <avr/io.h>
 #include <avr/eeprom.h>
 #include <util/delay.h>
+#include <avr/sleep.h>
+#include <avr/interrupt.h>
 
-uint16_t adcval EEMEM;
+uint16_t pwmee EEMEM;
 
 int main(void)
 {
+	char seen = 0;
+
 	TCCR1C = _BV(COM1D0) | _BV(COM1D1) | _BV(PWM1D);
 	TCCR1A = _BV(PWM1A) | _BV(PWM1B);
-	TCCR1B = 0x80 | _BV(CS13) | _BV(CS12);
+	TCCR1B = 0x80| _BV(CS13) | _BV(CS11);
+	TC1H  = 0x03;
 	OCR1C = 0xFF;
 	OCR1D = 0x20;
-	TCNT1 = 3;
+	TCNT1 = 0;
 	DDRB |= _BV( PB5 );
 	PORTB &= ~_BV( PB5 );
 
 	ADCSRA = _BV(ADEN) | _BV(ADATE) | _BV(ADPS1) | _BV(ADPS0);
 	ADMUX = _BV(REFS1) | _BV(MUX0);
-	ADCSRB = _BV(REFS2);
+	// ADCSRB = _BV(REFS2); 
 	DIDR0 = _BV(ADC1D) | _BV(AREFD);
 
-	ADCSRA |= _BV(ADSC);
-	_delay_ms(1000);
-	eeprom_write_word(&adcval, ADCW);
+	while (1) {
+		uint16_t pwm;
+		unsigned char pwmhi, pwmlo;
+
+		ADCSRA |= _BV(ADSC);
+
+		_delay_ms(100);
+
+		pwm = ADCW;
+		if (!seen) {
+			seen = 1;
+			eeprom_write_word(&pwmee, pwm);
+		}
+		if (pwm > 0x3C0)
+			pwm = 0x3C0;
+		if (pwm < 1)
+			pwm = 1;
+		pwmhi = pwm >> 8;
+		pwmlo = pwm & 0xFF;
+
+		TC1H = pwmhi;
+		OCR1D = pwmlo;
+	}
 
+	sleep_mode();
     DDRA |= _BV( PA0 );
     while( 1 ) { 
         PORTA |=  _BV( PA0 );
-- 
2.39.3