Ignition monitor: Initial commit

Implemented:
* sleep mode
* monitoring portb pin3
* switching portb pin4

Missing:
* shutdown guard time

.gitignore

@@ -0,0 +1,3 @@
+bin/
+objs/
+

.vscode/c_cpp_properties.json

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+{
+    "configurations": [
+        {
+            "name": "Linux",
+            "includePath": [
+                "${workspaceFolder}/**",
+                "/usr/lib/avr/include"
+            ],
+            "defines": [],
+            "compilerPath": "/usr/bin/gcc"
+        }
+    ],
+    "version": 4
+}

.vscode/settings.json

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+{
+    "files.associations": {
+        "interrupt.h": "c",
+        "io.h": "c",
+        "iotn85.h": "c",
+        "iotnx5.h": "c",
+        "sleep.h": "c"
+    }
+}

.vscode/tasks.json

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+{
+    // See https://go.microsoft.com/fwlink/?LinkId=733558
+    // for the documentation about the tasks.json format
+    "version": "2.0.0",
+    "type": "shell",
+    "command": "make",
+    "echoCommand": true,
+    "problemMatcher": {
+        "base": "$gcc",
+    },
+    "presentation": {
+        "focus": true,
+        "reveal": "always",
+        "panel": "shared",
+        "clear": true,
+    },
+    "tasks": [
+        {
+            "label": "all",
+            "args": ["all"],
+            "group": {
+                "kind": "build",
+                "isDefault": true
+            }
+        },
+        {
+            "label": "clean",
+            "args": ["clean"],
+            "group": {
+                "kind": "build",
+                "isDefault": true
+            }
+        },
+        {
+            "label": "flash",
+            "args": ["flash"],
+            "group": {
+                "kind": "build",
+                "isDefault": true
+            }
+        }
+    ]
+}

Makefile

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+CROSS_COMPILE ?= avr-
+
+TARGET_FILE ?= avr.elf
+
+MCU = attiny85
+DUDE_MCU = t85
+
+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 += -Iinclude
+
+DUDE_FLAGS = -p $(DUDE_MCU)
+DUDE_FLAGS += -P /dev/spidev0.0
+DUDE_FLAGS += -c linuxspi
+DUDE_FLAGS += -b 10000
+
+CC = $(CROSS_COMPILE)gcc
+AS = $(CROSS_COMPILE)as
+LD = $(CROSS_COMPILE)ld
+OBJCOPY = $(CROSS_COMPILE)objcopy
+SIZE = $(CROSS_COMPILE)size
+AVRDUDE = avrdude
+
+OBJ_DIR := objs
+BIN_DIR := bin
+SRC_DIR := src
+
+C_SRCS = $(wildcard $(SRC_DIR)/*.c)
+C_OBJS = $(patsubst %.c,$(OBJ_DIR)/%.o,$(notdir $(C_SRCS)))
+
+OBJS = $(C_OBJS)
+TARGET = $(BIN_DIR)/$(TARGET_FILE)
+
+.PHONY: all
+all: $(TARGET)
+
+$(TARGET): $(OBJS) Makefile
+	@mkdir -p $(BIN_DIR)
+	$(CC) $(LD_FLAGS) $(LINKER_SCRIPT) $(OBJS) $(LD_LIBS) -o $@ -Wl,-Map=$(BIN_DIR)/$(notdir $(basename $@)).map
+	$(OBJCOPY) -O ihex $(TARGET) $(subst .elf,.hex,$(TARGET))
+	$(SIZE) $@
+
+$(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 $@ $<
+
+.PHONY: clean
+clean:
+	rm -rf \
+	$(OBJS) \
+	$(patsubst %.o,%.d,$(OBJS)) \
+	$(TARGET) \
+	$(subst .elf,.map,$(TARGET)) \
+	$(subst .elf,.hex,$(TARGET))
+
+.PHONY: flash
+flash: $(TARGET)
+	gpio 22 off
+	$(AVRDUDE) $(DUDE_FLAGS) -U flash:w:$(subst .elf,.hex,$(TARGET))
+	gpio 22 on
+
+define makedep
+	$(CC) -MM -MF $3 -MP -MT $2 $4 $1
+endef
+
+ifneq ($(MAKECMDGOALS),clean)
+-include $($(subst .o,.d,$(OBJS))
+endif

src/main.c

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+#include <stdint.h>
+
+#define F_CPU 1000000UL
+
+#include <avr/interrupt.h>
+#include <avr/io.h>
+#include <avr/sleep.h>
+#include <avr/wdt.h>
+#include <util/delay.h>
+
+#define IGNITION_PIN    4
+#define POWER_PIN       3
+
+int main(void)
+{
+    DDRB = 0xff;
+    DDRB &= ~(1 << IGNITION_PIN);
+    PORTB |= (1 << PB0) | (1 << PB1) | (1 << PB2);
+
+    wdt_enable(WDTO_8S);
+    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();
+        }
+    }
+
+    return 0;
+}