Ondřej Hruška
cfdc18d3c4
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7 years ago | |
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lib | 7 years ago | |
.gitignore | 7 years ago | |
CMakeLists.txt | 7 years ago | |
LICENSE | 9 years ago | |
Makefile | 7 years ago | |
README.md | 9 years ago | |
avr-c-bp.pro | 9 years ago | |
main.c | 9 years ago | |
style.astylerc | 9 years ago |
README.md
AVR C Boilerplate
This is a basic boilerplate for programming AVRs in C.
The project aims to make programming Arduinos in C fun by providing support for basic functionality like GPIO and USART, so you can start developing without having the datasheet open all the time.
It is intended for ATmega328P (the chip in Arduinos), but can be easily adapted to other parts.
Requirements
Before you can start coding, you need to install a few software packages:
avrdude
- the flash toolavr-gcc
- compileravr-libc
- libc implementation for AVRavr-binutils
- utils for manipulating AVR binariesmake
- to run the Makefile
There's a good chance you already have make
, the rest should be in your
distribution's repos.
If you're on Arch:
# pacman -S base-devel avr-gcc avr-binutils avr-libc avrdude
If you're on Mac, you should be able to pull the stuff with brew.
Getting started
The provided main.c
is a good starting point - it contains some simple demo code.
You can compile it with make
and flash with make flash
.
Before you can flash
First, check that the avrdude
options in the file are correct for your system - especially
the device and speed.
# AVRDUDE settings
PROG_BAUD = 57600
PROG_DEV = /dev/ttyUSB0
PROG_TYPE = arduino
# Build the final AVRDUDE arguments
PROG_ARGS = -c $(PROG_TYPE) -p $(MCU) -b $(PROG_BAUD) -P $(PROG_DEV)
- Adjust
PROG_DEV
to the device your board is connected to. On Linux it's usually/dev/ttyUSB0
, but it can also be/dev/ttyACM0
or something else. On Mac, it'll be/dev/cu.xxx
. On Windows it's someCOMx
.
Linux and Mac users can usels /dev
to see their devices. Windows users will find this in their Device Manager. - You may also adjust the baudrate (
PROG_BAUD
). Some boards need115200
.
TIP: You can look what the Arduino IDE is using - it's running avrdude too.
Adding new files
- If you add a new C file to the project, add an entry for it's
.o
(object file, created by the compiler before linking) to theOBJS
list in the Makefile. - Similarly, if you add a new folder with header files, add it to
INCL_DIRS
. - In case you need
printf
(orprintf
with floats), enable the appropriate LD_FLAGS in the Makefile (it's well commented). Code size will - obviously - grow quite a bit.
Notes
- The Arduino UNO bootloader has a quirk where
Double Speed Asynchronous Mode
for USART is enabled by default, so if you set your baud rate to 9600, you'd really get 19200.
We correct this in theusart_init()
function to keep things consistent and to avoid confusion.
If you wish to turn this on however, you can do so by usingusart_set_2x(true)
.