feat(ex04): full ex04

ex04/Makefile

@@ -0,0 +1,53 @@
+AVR_LIBC_DIR=/tmp/avr-libc
+
+# Makefile
+MCU=atmega328p
+F_CPU=16000000
+CC=avr-gcc
+OBJCOPY=avr-objcopy
+CFLAGS=-nostdlib -std=c99 -Wall -Wextra -g -Os -mmcu=$(MCU) -DF_CPU=$(F_CPU) -I. -I$(AVR_LIBC_DIR)/include
+TARGET=main
+SERIAL=-P /dev/ttyUSB0 -b 115200
+
+
+SRC_DIR=.
+OBJ_DIR=build
+
+SRC_FILES=main.c
+OBJ_FILES=$(patsubst %.c,%.o,$(SRC_FILES))
+
+SRC=$(addprefix $(SRC_DIR)/,$(SRC_FILES))
+OBJ=$(addprefix $(OBJ_DIR)/,$(OBJ_FILES))
+
+all: flash
+
+re: fclean all
+
+fclean: clean
+clean:
+	rm -rf $(OBJ_DIR)
+	rm -f $(TARGET).hex
+
+hex: $(TARGET).hex
+
+flash: hex
+	avrdude -p $(MCU) -c arduino -U flash:w:$(TARGET).hex:i $(SERIAL) 
+
+$(OBJ_DIR)/$(TARGET).bin: $(OBJ)
+	$(CC) $(CFLAGS) $(OBJ) -o $@
+
+$(OBJ_DIR)/%.o: $(SRC_DIR)/%.c $(AVR_LIBC_DIR)/.CACHETAG
+	mkdir -p $(shell dirname $@)
+	$(CC) $(CFLAGS) -c $< -o $@
+
+
+$(TARGET).hex: $(OBJ_DIR)/$(TARGET).bin
+	$(OBJCOPY) -j .text -j .data -O ihex $< $@
+
+$(AVR_LIBC_DIR)/.CACHETAG:
+	rm -rf $(AVR_LIBC_DIR)
+	git clone --depth=1 https://github.com/avrdudes/avr-libc/ $(AVR_LIBC_DIR)
+	cd $(AVR_LIBC_DIR) && ./bootstrap
+	cd $(AVR_LIBC_DIR) && ./configure --build=`./config.guess` --host=avr
+	cd $(AVR_LIBC_DIR) && make -j
+	touch $(AVR_LIBC_DIR)/.CACHETAG

ex04/main.c

@@ -0,0 +1,55 @@
+#include <avr/io.h>
+#include <stdint.h>
+#include <util/delay.h>
+
+#include <stdbool.h>
+
+#define D1 PB0
+#define D2 PB1
+#define D3 PB2
+#define D4 PB4
+
+#define SW1 PD2
+#define SW2 PD4
+
+int main(void) {
+  DDRB |= _BV(D4);
+  DDRB |= _BV(D3);
+  DDRB |= _BV(D2);
+  DDRB |= _BV(D1);
+
+  DDRD &= ~(_BV(SW1));
+  DDRD &= ~(_BV(SW2));
+
+  PORTB |= _BV(D4);
+
+  uint8_t prev = 0;
+  uint8_t value = 0;
+  while (true) {
+    uint8_t cur = (PIND & (_BV(SW1) | _BV(SW2)));
+    if (prev & (_BV(SW1)) && !(cur & (_BV(SW1)))) {
+      value++;
+    }
+    if (prev & (_BV(SW2)) && !(cur & (_BV(SW2)))) {
+      value--;
+    }
+    prev = cur;
+    if (value & 0b0001)
+      PORTB |= (_BV(D1));
+    else
+      PORTB &= ~(_BV(D1));
+    if (value & 0b0010)
+      PORTB |= (_BV(D2));
+    else
+      PORTB &= ~(_BV(D2));
+    if (value & 0b0100)
+      PORTB |= (_BV(D3));
+    else
+      PORTB &= ~(_BV(D3));
+    if (value & 0b1000)
+      PORTB |= (_BV(D4));
+    else
+      PORTB &= ~(_BV(D4));
+    _delay_ms(20);
+  }
+}