From a8d7b7a282075cd0e29bfb7b94b2a120f82bbf7c Mon Sep 17 00:00:00 2001
From: Thomas Klaehn <tkl@blackfinn.de>
Date: Sun, 22 Dec 2019 20:27:17 +0000
Subject: [PATCH] timer0 ctc

---
 Makefile   | 20 +++++++++++---------
 src/main.c | 43 +++++++++++++++++++++----------------------
 2 files changed, 32 insertions(+), 31 deletions(-)

diff --git a/Makefile b/Makefile
index 06c930f..dcfc7c3 100644
--- a/Makefile
+++ b/Makefile
@@ -3,19 +3,21 @@ CROSS_COMPILE ?= avr-
 TARGET_FILE ?= avr.elf
 
 MCU = attiny85
-DUDE_MCU = t85
+# MCU = atmega8
 
-C_FLAGS += -Wall -Werror
+# C_FLAGS += -Wall -Werror
 C_FLAGS += -Os
 C_FLAGS += -mmcu=$(MCU)
-C_FLAGS += -ffunction-sections
-C_FLAGS += -fdata-sections
-C_FLAGS += -std=c11
-C_FLAGS += -pedantic
-C_FLAGS += -pedantic-errors
+# C_FLAGS += -ffunction-sections
+# C_FLAGS += -fdata-sections
+# C_FLAGS += -std=c11
+# C_FLAGS += -pedantic
+# C_FLAGS += -pedantic-errors
 C_FLAGS += -Iinclude
 
-DUDE_FLAGS = -p $(DUDE_MCU)
+LD_FLAGS += -mmcu=$(MCU)
+
+DUDE_FLAGS = -p $(MCU)
 DUDE_FLAGS += -P /dev/spidev0.0
 DUDE_FLAGS += -c linuxspi
 DUDE_FLAGS += -b 10000
@@ -49,7 +51,7 @@ $(TARGET): $(OBJS) Makefile
 $(OBJ_DIR)/%.o: $(SRC_DIR)/%.c
 	@mkdir -p $(dir $@)
 	@$(call makedep,$<,$@,$(patsubst %.c,%.d,$(OBJ_DIR)/$(notdir $<)),$(C_FLAGS))
-	$(CC) -c $(C_FLAGS) $(CCFLAGS) -o $@ $<
+	$(CC) -c $(C_FLAGS) -o $@ $<
 
 .PHONY: clean
 clean:
diff --git a/src/main.c b/src/main.c
index 0c9545b..d8623da 100644
--- a/src/main.c
+++ b/src/main.c
@@ -8,35 +8,34 @@
 #include <avr/wdt.h>
 #include <util/delay.h>
 
-#define IGNITION_PIN    4
-#define POWER_PIN       3
+volatile int tick;
 
 int main(void)
 {
+    cli();
+    tick = 0;
     DDRB = 0xff;
-    DDRB &= ~(1 << IGNITION_PIN);
-    PORTB |= (1 << PB0) | (1 << PB1) | (1 << PB2);
 
-    wdt_enable(WDTO_8S);
+    TCCR0A = (1 << WGM01);
+    TCCR0B = (1 << CS01);
+    TIMSK |= (1 << OCIE0A); // enable compare match interrupt
+
+    // ((1000000 / 8) / 1000) = 125
+    OCR0A = 125 - 1;
+
+    // TIMSK |= (1 << TOIE0);
+
+    sei();
     while(1) {
-        wdt_reset();
-        if(PINB & (1 << IGNITION_PIN)) {
-            PORTB |= (1 << POWER_PIN);
-        } else {
-            if(PINB & (1 << POWER_PIN)) {
-                for(uint8_t i = 0; i < 100; ++i) {
-                    wdt_reset();
-                    _delay_ms(100);
-                }
-                PORTB &= ~(1 << POWER_PIN);
-            }
-            wdt_enable(WDTO_8S);
-            set_sleep_mode(SLEEP_MODE_PWR_DOWN);
-            sleep_enable();
-            sleep_cpu();
-            sleep_disable();
+        if(tick >= 1000) {
+            PORTB ^= (1 << PB4);
+            tick = 0;
         }
     }
-
     return 0;
 }
+
+ISR(TIM0_COMPA_vect)
+{
+    tick++;
+}