From d994c95941de615c48350544b584b77501f05112 Mon Sep 17 00:00:00 2001
From: Jonathan Wyss <j.wyss@kolabnow.ch>
Date: Tue, 26 Mar 2024 18:44:33 +0100
Subject: [PATCH] stabilise sample rate

---
 main.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/main.c b/main.c
index 4a02df8..4b7e437 100644
--- a/main.c
+++ b/main.c
@@ -35,30 +35,32 @@ const float log_scale = 64./log(64./SCALE_FACTOR + 1.);
 
 
 int msec;
-
+uint16_t ticks;
 ISR(TIMER1_OVF_vect)
 {
-if(msec<100)
+if(ticks < 65000)
 {
-	msec++;
+		ticks++;
 }
-else msec=0;
+if(ticks > 65000)
+{
+		ticks=0;
+}
+
 }
 
 int main (void)
 {
 		int i,i2;
-		//int colorb;
-		//int colora;
 		int sum,avg;
 		char sample[64];
-		//char im[64];
 		char buff[64];
 
 		float fac_r=0.1;
 		float fac_g=0.1;
 		float fac_b=1;
 		msec=0;
+		ticks=0;
 		struct cRGB led_bar1[8];
 		//DDRB = (1<<mic);//would be setting output, default is input so no need for setting
 		setupADC();
@@ -81,9 +83,11 @@ int main (void)
 		{
 //######RECORD SAMPLES######
 				sum = 0;
+
+				ticks=0;
 				for(i=0;i<64;i++)
 				{	
-				msec=0;
+
 						STARTADC; 
 						sample[i] = (ADCH-128); //read Analog value register 8bit center -128
 						//sample[i] = (sample[i] <= NOISE) ? 0 : (sample[i] - NOISE);						  //noise reduction
@@ -91,8 +95,10 @@ int main (void)
 										//
 						sum+=sample[i];//dc-bias
 				
-						//while(msec<=1);
+
 				}
+
+												 //samplingrate -> 1/ca30'000'00r
 				avg = sum/64;//calculate bias
 				for(i=0;i<64;i++)
 				{
@@ -139,6 +145,7 @@ int main (void)
 						}
 				}				
 				ws2812_setleds(led_bar1,8);
+			while(ticks<60){ asm("");}//workaround for stoping gcc optimizing
 		}
 return 0;                 
 }
@@ -148,7 +155,7 @@ return 0;
 void setupTimer(void)
 {
 		clock_prescale_set(0);
-		TCCR1 = (1<<CS10);//(1<<CS13)|(1<<CS10)|(1<<CTC1);										//clear timer on compare match
+		TCCR1 = (1<<CS10);//|(1<<CS10)|(1<<CTC1);								/8		//clear timer on compare match
 		GTCCR = 0;												//default values should be ok
 		//OCR1C =	117;											//Compare value of timer / overflow , sets OCF1A
 		//OCR1A = 117;