Three-channel LED blinker

*.eep

*.elf

*.hex

*.o

PROGRAM=blinker

SRC=main.c

OBJ=$(SRC:.c=.o)

MCU=attiny25

AVRDUDE_MCU=$(MCU)

AVRDUDE_PROGRAMMER=usbasp

CFLAGS=-Wall -Os -mmcu=$(MCU) -DUSE_LOGGING=1 -DF_CPU=1000000UL -std=gnu99

LDFLAGS=

AVRDUDE_FLAGS= -p$(AVRDUDE_MCU) -c $(AVRDUDE_PROGRAMMER) -B100

FORMAT=ihex

CC=avr-gcc

OBJCOPY=avr-objcopy

OBJDUMP=avr-objdump

AVRDUDE=avrdude

all: $(PROGRAM).hex $(PROGRAM).eep

program: $(PROGRAM).hex $(PROGRAM).eep

	$(AVRDUDE) $(AVRDUDE_FLAGS) -U flash:w:$(PROGRAM).hex:i -U eeprom:w:$(PROGRAM).eep:i

program_flash: $(PROGRAM).hex

	$(AVRDUDE) $(AVRDUDE_FLAGS) -U flash:w:$(PROGRAM).hex:i

program_eeprom: $(PROGRAM).eep

	$(AVRDUDE) $(AVRDUDE_FLAGS) eeprom:w:$(PROGRAM).eep:i

dump_eeprom:

	$(AVRDUDE) $(AVRDUDE_FLAGS) -U eeprom:r:eeprom.raw:r

	od -tx1 eeprom.raw

objdump: $(PROGRAM).elf

	$(OBJDUMP) --disassemble $<

.PRECIOUS : $(OBJ) $(PROGRAM).elf

%.hex: %.elf

	$(OBJCOPY) -O $(FORMAT) -R .eeprom $< $@

%.eep: %.elf

	$(OBJCOPY) -j .eeprom --set-section-flags=.eeprom="alloc,load" \

		--change-section-lma .eeprom=0 -O $(FORMAT) $< $@

%.elf: $(OBJ)

	$(CC) $(CFLAGS) $(OBJ) -o $@ $(LDFLAGS)

%.o: %.c lights.h Makefile

	$(CC) -c $(CFLAGS) $< -o $@

%.s: %.c lights.h Makefile

	$(CC) -S -c $(CFLAGS) $< -o $@

%.o: %.S

	$(CC) -c $(CFLAGS) $< -o $@

clean:

	rm -f $(PROGRAM).hex $(PROGRAM).eep $(PROGRAM).elf *.o *.s eeprom.raw

version.c:

	./version.pl > version.c

.PHONY: all clean dump_eeprom program program_flash program_eeprom objdump version.c

#include <avr/io.h>

#include <util/delay.h>

#include <avr/sleep.h>

#include <avr/power.h>

/*

 * Overview:

 * three LEDs:

 * PB1/OC1A     yellow

 * PB2          yellow

 * PB4/OC1B     red

 */

static void init()

{

	DDRB |= _BV(PB1) | _BV(PB2) | _BV(PB4);

	// PWM setup, use T/C 1

	TCCR1 = _BV(CS10)	// clock at CLK/1

		| _BV(PWM1A)	// OCR1A in PWM mode

		| _BV(COM1A1);	// clear on compare match

	GTCCR = _BV(PWM1B)	// OCR1B in PWM mode

		| _BV(COM1B1); // clear on compare match)

	OCR1C = 255;

	OCR1A = 0;

	OCR1B = 0;

}

static unsigned char levels[] = {

	0, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 255

};

#define N_LEVELS (sizeof(levels)/sizeof(levels[0]))

static void led_set(unsigned char led, unsigned char val)

{

	switch (led) {

	case 0:

		OCR1A = val < N_LEVELS ? levels[val] : levels[N_LEVELS-1];

		break;

	case 1:

		if (val) {

			PORTB |= _BV(PB2);

		} else {

			PORTB &= ~_BV(PB2);

		}

		break;

	case 2:

		OCR1B = val < N_LEVELS ? levels[val] : levels[N_LEVELS-1];

		break;

	}

}

static unsigned char rand[] = {

193, 33, 133, 97, 139, 225, 40, 105, 110, 238, 57, 250, 26, 221, 166, 247, 138, 23, 107, 122, 154, 33, 201, 66, 154, 78, 137, 198, 86, 232, 38, 182, 16, 198, 73, 231, 58, 114, 58, 105,

};

#define N_RAND (sizeof(rand)/sizeof(rand[0]))

static void led0()

{

	static unsigned char r, l, exp;

again:

	if (l == exp) {

		r++;

		if (r > N_RAND-7)

			r = 0;

		exp = rand[r] >> 4;

		if (exp >= N_LEVELS-4)

			goto again;

	}

	if (l < exp) {

		l++;

	} else if (l > exp) {

		l--;

	}

	led_set(0, l);

}

static void led1()

{

	static unsigned char r;

	unsigned char exp;

	led_set(1, 1);

#if 0

again:

	r++;

	if (r > N_RAND)

		r = 0;

	exp = rand[r];

	led_set(1, ((exp >> 3) & 1) ^ ((exp >> 5) & 1));

#endif

}

static void led2()

{

	static unsigned char r, l, exp;

again:

	if (l == exp) {

		r++;

		if (r > N_RAND)

			r = 0;

		exp = rand[r] & 0xF;

		if (exp >= N_LEVELS)

			goto again;

	}

	if (l < exp) {

		l++;

	} else if (l > exp) {

		l--;

	}

	led_set(2, l);

}

int main(void)

{

	init();

	while (1) {

		led0();

		led1();

		led2();

		_delay_ms(40);

	}

}