Libmraa is a C/C++ library with bindings to javascript & python to interface with the IO on Galileo, Edison & other platforms, with a structured and sane API where port names/numbering matches the board that you are on. Use of libmraa does not tie you to specific hardware with board detection done at runtime you can create portable code that will work across the supported platforms.

The intent is to make it easier for developers and sensor manufacturers to map their sensors & actuators on top of supported hardware and to allow control of low level communication protocol by high level languages & constructs.

API

These interfaces allow you to interact with all libmraa functionality. The C++ classes directly wrap the C API and provide a near 1:1 mapping of functionality.

C API Modules	C++ API Classes
gpio	Gpio class
i2c	I2c class
aio	Aio class
pwm	Pwm class
spi	Spi class
uart	Uart class
common	common

Hello Mraa

#include "mraa.h"
int
main(int argc, char **argv)
{
    char* board_name = mraa_get_platform_name();
    fprintf(stdout, "hello mraa\n Version: %s\n Running on %s\n", mraa_get_version(), board_name);
    mraa_deinit();
    return MRAA_SUCCESS;
}

Supported platforms

Specific platform information for supported platforms is documented here:

DEBUGGING

Sometimes it just doesn't want to work, let us try and help you, you can file issues in github or join us in mraa on freenode IRC, hang around for a little while because we're not necessarily on 24/7, but we'll get back to you! Have a glance at our page too

COMPILING

More information on compiling is Building libmraa page.

CONTRIBUTING

Please see the Contributing to libmraa page, the libmraa Internals page may also be of use.

API Changelog

This changelog is meant as a quick & rough guide to what has changed between versions. The API is now fairly stable but when new calls/features are added they are listed here. Anything pre 0.2.x is ignored.

0.6.0

add device path queries for uart
add platform configuration querying
gpio sample added
improve i2c/spi write/read API for python & nodejs
performance improvements on edison & galileo

0.5.4

pwm read_* fix introduced in 0.5.3
improved npmpkg support

0.5.3

OE toolchain support added to CMake
Various UART fixes
SPI add CS exposure
Remove functions from mraa.c into modules
Rework of support for mmap
Intel Edison MMAP support added. Read and Write
I2C clean up, add cleaner functions
MinnowBoard Max support added
PWM period is written before duty
Node GYP build supported added
Add Get Platform Name function

0.5.2

pwm improvement & bugfix
spi mraa_spi_bit_per_word fix
new spi transfer function
i2c object api uses uint8_t
i2c readReg() calls added
edison i2c bus now defaults to a sensible value
edison uart enable support
edison hardware CS exposed as IO10
DE3815tykhe NUC support

0.5.1

Intel Edison - Mini breakout board support
Change to use syslog throughout instead of printing to stderr.
Fix misc issues brought up throuh coverity scans
Clear up Analog call documentation

0.5.0

Intel Edison - Arduino board support.
Boost Allowable i2c busses to 12
Additional platform hooks added
ADC is now 10bits by default on all platforms but can be changed

0.4.5

if only one spidev we default to it reguardless of number
mraa_pwm_config_ms & mraa_pwm_config_percent functions added
Uart C++ class added, adds python & node support
galileo gen2 gpio modes supported

0.4.4

prefix SPI mode with MRAA_SPI_
added C++ adc bitness calls

0.4.3

SPI Mode function now functional, API Change in SPI
I2C read in swig worked on.
Galileo Gen 2: PWM setting period sets all channel's period
Galileo Gen 2: I2C setup now specific to Gen 2.
General commits around freeing memory at the right times.

0.4.2

Barebone UART module added.
Hook branch merged.
I2C init hooks added.
Intel Galileo Gen 2, I2C gpio pins now go hiz input when I2C initialised.

0.4.1

Rename python & nodejs modules to mraa
common.hpp introduced for C++
python & nodejs modules can now take binary strings for Spi & I2c
improved Aio module and clear bitness
Improved Galileo Gen 2 support

0.4.0

Rename to mraa
get_platform_type function added.

0.3.1

Initial Intel Galileo Gen 2 support
mraa_gpio_isr parameters added.
Detection of different supported platforms added.

0.3.0

mraa_i2c_read now returns length of read

0.2.9

Add global mraa.h & mraa.hpp headers
usage of "gpio.h" is not legal you need to use "mraa/gpio.h" unless adding -L/usr/include/mraa

0.2.8

Added mraa_set_priority call
Added mmap gpio call mraa_gpio_use_mmaped

0.2.7

C++ API now uses basic types and not unistd types as C
Clearer and consistent use of unistd tpyes in C api

0.2.6

C++ examples added, using c++ headers/api.
moved to open instead of fopen in all modules
rename mraa_check functions and made them internal to mraa only.
removed "export" functions from api
Intel Galileo Gen 1 (rev d) fixes, incorrect definition of some items
SPI, implementation completed.
I2C internal function, completed.
PWM fix bug in period set method.
Swig upstream can be used for building.
No longer builds docs on default cmake, needs flag
GPIO/PWM ownership guard prevents closing on existing pins, still can be forced.

0.2.5

C++/Python/Node Enums/const names now do not contain MRAA_GPIO
Enum type declaration for C++ changed
Python/Node get_version() -> GetVersion()
i2c read calls don't use const char* and i2c write calls do

0.2.4

All mraa_ contexts now are pointers to the actual struct which is not delcared in the header. The only end user change is that instead of returning a type mraa_gpio_context pointer mraa_gpio_init() now returns a mraa_gpio_context (which is actually a pointer to struct _gpio internally).
C++ API is available, use the .hpp headers and add stdc++ to the linker flags.
Initial SPI implementation is provided

0.2.3

mraa_aio_read_u16() -> mraa_aio_read()
mraa_aio_read() now returns a uint16_t instead of an unsigned int

0.2.2

First version with API considered 'stable'