ATtiny ICs

The ATtiny's in the IC' s drawer of the wooden cupboard are nice to program for many different uses. Below is an example code (blink.c) that just blinks the pin op PB0 (pin 12) of an attiny2313.

Below is a makefile that you can use to build the code, and flash it onto the chip. Wire the USBTinyISP onto the breadboard with the ATtiny. Apart from the USBTinyISP only the VCC and GND are needed on the ATTiny. Then put the blink.h in a folder, put the makefile in there as well and run

make all
sudo make install

And it should work. In the makefile the CLOCK variable specifies the frequency (so 8MHz below). The FUSES specify a bunch of things in the chip that are important (oa for the clock frequency, but others too). See http://www.engbedded.com/fusecalc to calculate these fuse settings. Take the +65ms delay, divide clock by 8 internally and SPI program download enabled. That should give the proper fuses, and only requires you to specify if you need an internal or external crystal osc and which frequency.

#include <avr/io.h>

#define LED PB0

void delay_ms(uint16_t ms) {
    uint16_t delay_count = 1000000 / 17500;
    volatile uint16_t i;
    
    while (ms != 0) {
        for (i=0; i != delay_count; i++);
        ms--;
    }
}

int main(void) {
    
    DDRB = (1<<LED);
    
    for(;;) {
        PORTB = (1<<LED);
        delay_ms(1000);
        PORTB = ~(1<<LED);
        delay_ms(1000);
    }
    
    return 0;
}

# Name: Makefile
# Author: <insert your name here>
# Copyright: <insert your copyright message here>
# License: <insert your license reference here>

# This is a prototype Makefile. Modify it according to your needs.
# You should at least check the settings for
# DEVICE ....... The AVR device you compile for
# CLOCK ........ Target AVR clock rate in Hertz
# OBJECTS ...... The object files created from your source files. This list is
#                usually the same as the list of source files with suffix ".o".
# PROGRAMMER ... Options to avrdude which define the hardware you use for
#                uploading to the AVR and the interface where this hardware
#                is connected. We recommend that you leave it undefined and
#                add settings like this to your ~/.avrduderc file:
#                   default_programmer = "stk500v2"
#                   default_serial = "avrdoper"
# FUSES ........ Parameters for avrdude to flash the fuses appropriately.

DEVICE     = attiny2313
CLOCK      = 8000000
PROGRAMMER = -c usbtiny -p attiny2313
OBJECTS    = blink.o
FUSES      = -U hfuse:w:0xdf:m -U lfuse:w:0x64:m

# For computing fuse byte values for other devices and options see
# the fuse bit calculator at http://www.engbedded.com/fusecalc/


# Tune the lines below only if you know what you are doing:

AVRDUDE = avrdude $(PROGRAMMER) -p $(DEVICE)
COMPILE = avr-gcc -Wall -Os -DF_CPU=$(CLOCK) -mmcu=$(DEVICE)

# symbolic targets:
all:	main.hex

.c.o:
	$(COMPILE) -c $< -o $@

.S.o:
	$(COMPILE) -x assembler-with-cpp -c $< -o $@
# "-x assembler-with-cpp" should not be necessary since this is the default
# file type for the .S (with capital S) extension. However, upper case
# characters are not always preserved on Windows. To ensure WinAVR
# compatibility define the file type manually.

.c.s:
	$(COMPILE) -S $< -o $@

flash:	all
	$(AVRDUDE) -U flash:w:main.hex:i

fuse:
	$(AVRDUDE) $(FUSES)

# Xcode uses the Makefile targets "", "clean" and "install"
install: flash fuse

# if you use a bootloader, change the command below appropriately:
load: all
	bootloadHID main.hex

clean:
	rm -f main.hex main.elf $(OBJECTS)

# file targets:
main.elf: $(OBJECTS)
	$(COMPILE) -o main.elf $(OBJECTS)

main.hex: main.elf
	rm -f main.hex
	avr-objcopy -j .text -j .data -O ihex main.elf main.hex
	avr-size --format=avr --mcu=$(DEVICE) main.elf
# If you have an EEPROM section, you must also create a hex file for the
# EEPROM and add it to the "flash" target.

# Targets for code debugging and analysis:
disasm:	main.elf
	avr-objdump -d main.elf

cpp:
	$(COMPILE) -E main.c