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This commit introduces support for Dallas Semiconductor (DS) 1-wire compliant device support using an available UART device. The principle of operation is described in the following Application note by Maxim Electronics: https://www.maximintegrated.com/en/app-notes/index.mvp/id/214 with help (1-wire search) from: https://www.maximintegrated.com/en/app-notes/index.mvp/id/187 It has been tested on Galileo 2 and Edison, with 2 DS 1-wire devices, the DS18B20 and DS2413 connected to the bus. A UPM driver for the DS2413 is already complete and a PR will be submitted after this one. It is important that you use a UART with CMOS/TTL level voltages (3.3v/5v) RX and TX lines. DO NOT use standard RS232 level voltages or you are going to have a bad day. In order for this to work, a simple interface circuit, using a single diode must be constructed: (forgive my "Asciihematic" :) -| U| A| TX---|<--+ R| | T| RX-------o--------o 1-wire data bus -| The diode on TX is a 1N4148 (cheap and common), with the cathode connected to TX, and the anode connected to RX and the 1-wire data line. The 1-wire data line requires a pull-up resistor, as the DS 1-wire spec requires. 4.7-5K is typical for DS 1-wire buses. NOTE: DHT-type (temp/humidity sensor) 1-wire devices ARE NOT DS 1-wire compliant, and will not work with this code/circuit unfortunately. Also note, this will use up one of your UARTs, which cannot be used for any other purpose (ie: to access true UART-type serial devices). You can however, connect as many DS 1-wire devices as feasible to this UART, as it will function as a DS 1-wire bus master. Signed-off-by: Jon Trulson <jtrulson@ics.com> Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
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.
Supported Boards
X86
- Galileo Gen 1 - Rev D
- Galileo Gen 2 - Rev H
- Edison
- Intel DE3815
- Minnowboard Max
- NUC 5th generation
- UP
ARM
USB
Installing on your board
See the section below on compiling or use our repository to install on a glibc based yocto poky image that supports opkg. Adding this repository is as simple as and you'll have the latest stable tagged build of mraa installed!
echo "src mraa-upm http://iotdk.intel.com/repos/3.0/intelgalactic/opkg/i586" > /etc/opkg/mraa-upm.conf
opkg update
opkg install mraa
If you would like to get the latest & greatest builds from master HEAD you can use our -dev repository
echo "src mraa-upm http://iotdk.intel.com/repos/3.0/intelgalactic-dev/opkg/i586" > /etc/opkg/mraa-upm.conf
opkg update
opkg install mraa
You can also install just the node.js mraa module by using npm. You will need a C++ compiler and the node development headers, however it's not required to have SWIG installed.
npm install mraa
Compiling
See documentation on building
Examples
See the examples available for various languages
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 debugging page too.
API Documentation
Contact Us
To ask questions either file issues in github or send emails on our mailing list. You might also catch us on the mraa channel on freenode IRC.
See the Contribution documentation for more details.
Changelog
Version changelog here.