Onward.. By Iron Will

Well, it's been quite some time since my last entry to this electrostatic thought-log of the world-wide grids. I'll tear off a new sheet and hastily inscribe an entry describing my latest adventures, digital and otherwise.

So on the Iron front, I've been busy adding some new features that will hopefully help users migrate from the official IDE. There is now a notion of a "Sketch", which is composed of two graphs: one for each of the 'setup()' and 'loop()' functions. Just like the official IDE, the setup graph is run once on device start-up, with the loop graph running continuously afterward.

I've also added text fields to variables, allowing them to have numeric values assigned. To be sure a small advance, but a forward one thankfully.

Below is a snapshot of the Setup and Loop graphs with a simple sketch that sets up pins, reads an analog value and maps/constrains it to a range.

The next step is to compile the graph into source code, which is then uploaded and run on the MCU. Wish me luck, dear Reader of the Aetheric Voids. It is truly all about the journey :-)

~M

An Ironclad Premise

I've been busy lately with the library that I'm hoping will form the foundation of my work with Arduino. It is titled 'Iron', and offers various interfaces for physical computing tasks. The library is based around the concept of devices, encouraging the designer to build code in a fashion that mirrors the physical unit they are creating.

There is a strong theme of performance to the code and, where possible, the lowest-level interfaces are used. For example, direct port manipulation is accomplished with template meta-programming, allowing comfortable labels to be used in place of bit shifts:

// Set pin mode as output. Equivalent to: 'DDRB |= ( 1 << 5 );'
//
setMode< 13, OUTPUT >();

// Set pin 13 high. Equivalent to: 'PORTB |= ( 1 << 5 );'
//
setDigital< 13, HIGH >();

The notion of a device is a cornerstone of the library, gathering variables, communication and inputs & outputs in one place. For example, a camera device might be defined as:

// Define device
//
EN_DEFINE_DEVICE(
    (( Camera, "Example camera device", 0xB0, 0x7B, 0xA6, 0x43 )
    (( Input,    shutter, digital_t, Low,     2 ))
    (( Input,    zoom,    analog_t,  512,     A0 ))
    (( Internal, model,   uint32_t,  2389221, None ))
    (( Internal, flash,   bool,      true,    None ))
    (( Output,   led,     digital_t, Low,     13 ))
)


Devices are designed to be interacted with from either the CPU or the MCU. Following is an example of how a camera's shutter might be expressed with Arduino:

// Create device, with MCU view
//
Camera< MCU > g_cam;

void setup()
{
    // Set up pin modes for any mapped attributes
    //
    g_cam.setup()
}

void loop()
{
    // If shutter button is 'HIGH', begin read of image data
    //
    if ( g_cam.is< 0, HIGH >() )
    {
        g_cam.read< Image >( buffer );
    }
}


From the CPU side it is possible to scan a bus for devices, establishing connections where required:

std::vector< Camera< CPU > > devices = scan< Camera >();

for ( auto it = devices.begin(); it != devices.end(); ++it )
{
    select( *it );   // Select a device. Ready for signals, etc.
    deselect( *it ); // Deselect a device.
}


There are many more facets yet to explore in the library, but it felt right to release it now. It is licensed under the GPL: you are free to use it as-is, or hack it to pieces as you see fit :) Enjoy!

https://github.com/engine-develop/iron

The Iron Handshake

After a brief reprieve from the world of circuits (and their bending) I decided to begin work on the codebase for the S1 sensor. The first forays have been into bus communication, with a simple templated foundation in the works. Often the pattern of bus operations is fixed, with variation in the data layout and signals. The library, called Iron, exposes only the essential components, hiding the details (read: gory) of bus management from the user.

For the S1 project the main role of the bus will be the transfer of image buffers. The library scans all serial ports, signalling to any devices that satisfy a signature. A device matching the protocol is connected to, enabling the start of bus operations.

EN_DEFINE_BUS_PROTOCOL( IR, 16, 0xB0, 0x7B, 0xA6 )
std::vector< Device > devs = Bus< IR, CPU >::listDevices( All );
Bus< IR, CPU >::connect( devs[0], baudRate );
Bus< IR, MCU >::write( image);

The video below shows a simple handshake between a PC application with an Arduino using the Bluetooth Serial Port Protocol. The LED blinks once to indicate a successful handshake. The next step is to send some image data from the Arduino, maybe using sensor values... or I bin it ;)