fix timer 3 unavailable on m324

use timer 0 (whith less precission)

Firmware/src/music.c

@@ -80,30 +80,49 @@ void pwm_init (void)
 	TCCR1B = _BV(CS10) | _BV(WGM12); //fast PWM (8 bit), clk/1  source
 	
 	//setup sample timer (CTC Mode)	
+#if defined(__AVR_ATmega1284P__)
 	TCCR3A = 0; 
 	TCCR3B = _BV(CS30) | _BV(WGM32); // clk/1
+#elif defined(__AVR_ATmega324PA__)
+	TCCR0A = _BV(WGM01);
+	TCCR0B = _BV(CS01); // clk/8
+#endif
 }
 
 void pwm_deinit (void)
 {	
 	TCCR1A = 0;
 	TCCR1B = 0;	
+#if defined(__AVR_ATmega1284P__)
 	TCCR3A = 0;
 	TCCR3B = 0; 
+#elif defined(__AVR_ATmega324PA__)
+    TCCR0A = 0;
+    TCCR0B = 0;
+#endif
 }
 
 void pwm_gen(uint16_t tone, uint16_t periods)
 {
 	//calculate single sine sample duration
+#if defined(__AVR_ATmega1284P__)
 	OCR3A = F_CPU / tone / sizeof(sine_lookup) - 1;
-		
+#elif defined(__AVR_ATmega324PA__)
+	OCR0A = F_CPU / 8 / tone / sizeof(sine_lookup) - 1;
+#endif
+
 	for (uint16_t period=0; period < periods; ++period)  {
 		for (uint8_t spl=0; spl < sizeof(sine_lookup); ++spl) {
 			//wait for timer ready for next spl
+#if defined(__AVR_ATmega1284P__)
 			loop_until_bit_is_set(TIFR3, OCF1A);	
 			TIFR3 = _BV(OCF1A); //clear OCF
+#elif defined(__AVR_ATmega324PA__)
+			loop_until_bit_is_set(TIFR0, OCF0A);
+			TIFR0 = _BV(OCF0A); //clear OCF
+#endif
 			
 			OCR1A = pgm_read_byte(sine_lookup + spl) + 0x70;
 		}	
 	}	
-}
+}