Code samples for basic AVR ATtiny programming

This to go with the following Google Slides presentation.

blink_busywait

Very basic example of blinking an LED in a naive busy-wait loop

blink_busywait_5_leds

Basic example of blinking 5 LED's in a naive busy-wait loop

blink_timer_interrupt

Using hardware timer interrupt to blink an LED more effeciently

blink_watchdog_interrupt

Using hardware watchdog interrupt to blink an LED very effeciently

blink_hardware_pwm

Using Pulse Width Modulation (timers) to fade an LED

button_press_interrupt

Using a hardware interrupt to detect and react to a button being pressed

mailbox_notifier_polling

Small but complete practical example of starting blinking a LED when a mailbox receives mail and turning it off when emptying mailbox

#Howto

##Install Install the AVR GCC toolchain plus some programming software and use your favorite IDE. Sane developers would use Mac or Linux, I prefer the Debian variety of Linux so if you're on Ubuntu, Mint etc. simple do: sudo apt-get install avr-libc binutils-avr gcc-avr avrdude avarice gdb-avr

##Make The samples use standard C make files, borrowed from WinAVR. This means compiling, linking, flashing etc. is taken care of with one command. The Makefile have a few constants you may want to tweak if you are not using the usbasp programmer or the ATtiny13 MCU.

• make all = Make software.
• make clean = Clean out built project files.
• make coff = Convert ELF to AVR COFF.
• make extcoff = Convert ELF to AVR Extended COFF.
• make program = Download the hex file to the device, using avrdude.
• make debug = Start either simulavr or avarice as specified for debugging, with avr-gdb or avr-insight as the front end for debugging.
• make filename.s = Just compile filename.c into the assembler code only.

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