From 927276afb576d5a6eb219831dfb182d63bc3969f Mon Sep 17 00:00:00 2001
From: Marco <mgross@sw-gross.de>
Date: Mon, 30 May 2022 06:10:18 +0200
Subject: [PATCH] 1. Remove ISR for Timer0 Compare Unit. 2. Change chip select
 but keep 1kHz frequency of Timer1 PWM.

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

diff --git a/src/timer.c b/src/timer.c
index fa91321..d0428c1 100644
--- a/src/timer.c
+++ b/src/timer.c
@@ -8,12 +8,18 @@
 
 void initPwmTimer1(void)
 {
+	/*
+	 * We are using Timer 1 Compare Match Unit B.
+	 * OC1B is on Pin PB6. Let's make it an output.
+	 */
+	DDRB |= (1 << DDB6);
+
 	/* Enable Fast PWM with TOP in OCR1A */
 	TCCR1A |= (1 << WGM11) | (1 << WGM10);
 	TCCR1B |= (1 << WGM13) | (1 << WGM12);
 
-	/* Clock prescaler of 8 */
-	TCCR1B |= (1 << CS11);
+	/* Clock prescaler of 64 */
+	TCCR1B |= (1 << CS11) | (1 << CS10);
 
 	/* Set OC1B on compare match, clear OC1B at TOP */
 	TCCR1A |= (1 << COM1B1);
@@ -22,10 +28,10 @@ void initPwmTimer1(void)
 	TIMSK1 |= (1 << OCIE1B);
 
 	/* TOP value */
-	OCR1A = 1000;
+	OCR1A = 125;
 
 	/* Compare Match with OCR1B */
-	OCR1B = 10;
+	OCR1B = 62;
 }
 
 void initCtcTimer0(void)
@@ -62,16 +68,3 @@ void initOverflowTimer1(void)
 	TCCR1B |= (1<<CS11);
 	TIMSK1 |= (1<<TOIE1);
 }
-
-volatile double sin_op = 0.0;
-volatile uint8_t wait_cnt = 0;
-
-ISR(TIMER0_COMPA_vect)
-{
-	if (wait_cnt > 0) {
-		printf("%.2lf\n\r", sin(sin_op));
-		sin_op = ((sin_op + 0.01) > 2*M_PI) ?  0.0 : sin_op + .01;
-		wait_cnt = 0;
-	}
-	wait_cnt++;
-}