Getting started

Overview

Microblx is a very lightweight function block model and implementation.

  • block: the basic building block of microblx. Is defined by filling in a ubx_block_t type and registering it with a microblx ubx_node_t. Blocks have configuration, ports and operations.

    Each block is part of a module and becomes available once the module is loaded in a node.

    There are two types of blocks: computation blocks (“cblocks”, BLOCK_TYPE_COMPUTATION) encapsulate “functionality” such as drivers and controllers. interaction blocks (“iblocks”, BLOCK_TYPE_INTERACTION) are used to implement communication or interaction between blocks. This manual focuses on how to build cblocks, since this is what most application builders need to do.

    • configuration: defines static properties of blocks, such as control parameters, device file names etc.
    • port: define which data flows in and out of blocks.

  • type: types of data sent through ports or of configuration must be registered with microblx.

  • node: an administrative entity which keeps track of blocks and types. Typically one per process is used, but there’s no constraint whatsoever.

  • module: a module contains one or more blocks or types that are registered/deregistered with a node when the module is loaded/unloaded.

Installation

Dependencies

  • uthash (apt: uthash-dev)
  • luajit (>=v2.0.0) (apt: luajit and libluajit-5.1-dev) (not
    strictly required, but recommended)
  • uutils Lua utilities git
  • liblfds lock free data structures (v6.1.1) git
  • autotools etc. (apt: automake, libtool, pkg-config, make)

Only for microblx development:

  • lua-unit (apt: lua-unit, git) (to run the tests)
  • cproto (apt: cproto) to generate C prototype header file

Building and setting up

Using yocto

The best way to use microblx on an embedded system is by using the meta-microblx yocto layer. Please see the README in that repository for further steps.

Building manually

Building to run locally on a PC.

Before building microblx, liblfds611 needs to be built and installed. There is a set of patches in the microblx repository to clean up the packaging of liblfds. Follow the instructions below:

Clone the code:

$ git clone https://github.com/liblfds/liblfds6.1.1.git
$ git clone https://github.com/kmarkus/microblx.git
$ git clone https://github.com/kmarkus/uutils.git

First build lfds:

$ cd liblfds6.1.1
$ git am ../microblx/liblfds/*.patch
$ ./bootstrap
$ ./configure --prefix=/usr
$ make
$ sudo make install

Then install uutils:

$ cd ../uutils
$ sudo make install

Now build microblx:

$ cd ../microblx
$ ./bootstrap
$ ./configure
$ make
$ sudo make install

Quickstart

NOTE: the following assume microblx was installed in the default locations under /usr/local/. If you installed it in a different location you will need to adopt the path to the examples.

Run the random block example

This (silly) example creates a random number generator block. It’s output is hexdump’ed (using the hexdump interaction block) and also logged using a file_logger block.

Before launching the composition, it is advisable to run the logging client to see potential errors:

$ ubx_log

and then in another terminal:

$ ubx_ilaunch -webif -c /usr/local/share/ubx/examples/systemmodels/trig_rnd_hexdump.usc

Browse to http://localhost:8888

Explore:

  1. clicking on the node graph will show the connections
  2. clicking on blocks will show their interface
  3. start the file_log1 block to enable logging
  4. start the ptrig1 block to start the system.