Fix timer interrupt priority + refactor

1 files changed, 8 insertions, 79 deletions

diff --git a/src/main.c b/src/main.c
index b3fa431..cf6f7a8 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,10 +1,10 @@
 #include <avr/interrupt.h>
 #include <avr/io.h>
 #include <stdbool.h>
-#include <stdint.h>
 #include <util/delay.h>
 
 #include "display.h"
+#include "rtc.h"
 
 // Config for attiny84a + external 32KHz crystal osc taken from
 // https://github.com/ingepnet/breadboardwatch/blob/master/Makefile#L26
@@ -15,68 +15,13 @@ FUSES = {
     .extended = 0xff,
 };
 
-void set_all_pins_output(void) {
-  DDRA |= 0b11111111;
-  DDRB |= 0b11111111;
-}
-
-void setup_rtc() {
-  // Set prescaler (Timer clock = F_CPU / 1024)
-  // For 32768Hz -> 32768/1024 = 32Hz
-  TCCR0B = (1 << CS02) | (1 << CS00) | (1 << WGM02);
-  TCCR0A = (1 << WGM01) | (1 << WGM00);
-
-  TCNT0 = 0;  // Start counting from 0
-  OCR0A = 31; // 0-31 = 32 counts before timer interrupt (1Hz)
-  OCR0B = 0;
-
-  // TIFR0 = (1 << TOV0);  // Clear interrupt flags
-  TIFR0 = (1 << OCF0A) | (1 << OCF0B) | (1 << TOV0); // Clear interrupt flags
-  // TIMSK0 = (1 << TOIE0); // Enable timer overflow interrupt
-  TIMSK0 = (1 << OCIE0A); // Enable timer overflow interrupt
-}
-
-volatile uint8_t seconds = 10;
-volatile uint8_t minutes = 0;
-volatile uint8_t hours = 0;
-// Clock
-ISR(TIM0_COMPA_vect, ISR_FLATTEN) {
-  // if (true) {
-  //   OCR0A = 32;
-  // } else if (true) {
-  //   OCR0A = 31;
-  // } else {
-  //   OCR0A = 30;
-  // }
-
-  uint8_t s = seconds + 1;
-  seconds = s % 60;
-  if (s >= 60) {
-    uint8_t m = minutes + 1;
-    minutes = m % 60;
-    if (m >= 60) {
-      hours = (hours + 1) % 24;
-    }
-  }
-}
-
-volatile static uint8_t digit_mask = 0b0001;
 // Display
-ISR(TIM1_COMPA_vect, ISR_FLATTEN) {
-  set_all_pins_output();
-  write_time(minutes, seconds, digit_mask);
-  if (seconds % 2) {
-    PORTA &= ~(1 << PA5);
-    PORTB &= ~(1 << PB3);
-  } else {
-    PORTA |= (1 << PA5);
-    PORTB |= (1 << PB3);
-  }
+// timer 0 has lower priority than timer 1, so some ticks could get skipped due
+// to interrupt starvation
+ISR(TIM0_COMPA_vect, ISR_FLATTEN) { display_render(); }
 
-  digit_mask = digit_mask << 1;
-  if (digit_mask > 0b1000)
-    digit_mask = 0b0001;
-}
+// RTC interrupt
+ISR(TIM1_COMPA_vect, ISR_FLATTEN) { rtc_increment(); }
 
 #define IS_BUTTON_ON() ((PINA & (1 << PA0)) == 0)
 #define ENABLE_BUTTON() (DDRA &= ~(1 << PA0))
@@ -84,28 +29,12 @@ ISR(TIM1_COMPA_vect, ISR_FLATTEN) {
 int main(void) {
   PRR = 0b0011; // Power reduction register. Shut down USI and ADC
 
-  setup_rtc();
-  setup_display();
+  display_setup();
+  rtc_setup();
 
   sei();
 
-  set_all_pins_output();
-
   while (1) {
-    // cli();
-    // set_all_pins_output();
-    // write_time(minutes, seconds, digit_mask);
-    // if (seconds % 2) {
-    //   PORTA &= ~(1 << PA5);
-    //   PORTB &= ~(1 << PB3);
-    // } else {
-    //   PORTA |= (1 << PA5);
-    //   PORTB |= (1 << PB3);
-    // }
-    // digit_mask = digit_mask << 1;
-    // if (digit_mask > 0b1000)
-    //   digit_mask = 0b0001;
-
     // ENABLE_BUTTON();
     // if (IS_BUTTON_ON()) {
     //   cli();