From 517d5896503d75132a74fccd8f9a79ea01a7c829 Mon Sep 17 00:00:00 2001
From: Lea <lea@janderedev.xyz>
Date: Tue, 29 Aug 2023 18:52:13 +0200
Subject: [PATCH] interrupts but real

---
 main.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/main.c b/main.c
index d7eaf66..de4f1f2 100644
--- a/main.c
+++ b/main.c
@@ -10,19 +10,20 @@
 #include "lib/7segment.h"
 #include "lib/7segment_4digits.h"
 
-volatile int ticks = 0;
+int timer_start =  0xffff - (F_CPU / 1024 / 1000);
+volatile uint32_t ticks = 0;
 
 // https://gist.github.com/Wollw/2381139
 void start_timer() {
     // Sets the Clock Select. See table on page 157 the Atmel datasheet.
-    TCCR1B |= _BV(CS10) | _BV(CS12);
+    TCCR1B |= _BV(CS10) | _BV(CS12); // clk/1024
 
     // Set the TOIE (Timer Overflow Interrupt Enable) bit
     // on TIMSK1 (Timer 1 Interrupt Mask Register).
     TIMSK1 |= _BV(TOIE1);
 
     // Sets the current timer value
-    TCNT1 = 63974;
+    TCNT1 = timer_start;
 
     // Enable interrupts
     sei();
@@ -36,8 +37,8 @@ void main() {
 // ISR is used to handle interrupts. TIMER1_OVF_vect
 // is triggered whenever timer 1 (16 bit) overflows.
 ISR(TIMER1_OVF_vect) {
-    TCNT1 = 63974; // TODO figure out how to get the correct number
-    ticks++;
+    TCNT1 = timer_start; // TODO figure out how to get the correct number
+    ticks += 1;
 }
 
 void prog_7segment() {
@@ -76,7 +77,7 @@ void prog_7segment_4digit() {
     bool pressed = false;
 
     while(1) {
-        show_float(ticks);
+        show_float(ticks / 1000.0f);
         float sleep_time = update_display();
 
         if (!pressed && bit_is_clear(PINK, PINK7)) {