[Home]Using HAL In Python

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Pygtk and HAL


Here is sample python code that shows how to create a custom widget
(an LED) and how to connect to HAL with python: upload:pygtk_HAL.py
upload:pygtk_HAL.png

To run the program with realtime:
cd to the folder that pygtk.py is in.
type 'halrun'
type 'loadusr python pygtk.py'

If using simulator
cd to folder type 'python pygtk.py'

I found this pages informative about custom widgets: http://zetcode.com/tutorials/pygtktutorial/customwidget/
http://www.learningpython.com/2006/07/25/writing-a-custom-widget-using-pygtk/
http://www.pygtk.org/articles/cairo-pygtk-widgets/cairo-pygtk-widgets.htm
http://www.pygtk.org/articles/cairo-pygtk-widgets/cairo-pygtk-widgets2.htm

and for general pygtk info: http://www.pygtk.org/pygtk2tutorial/index.html
http://www.pygtk.org/docs/pygtk/index.html
http://www.pygtk.org/articles.html

This is some of the info from the python imported module hal:

Help on module hal:

NAME
    hal - Interface to emc2's hal

FILE
    /home/chester/emc2-dev/lib/python/hal.so

DESCRIPTION
    This module allows the creation of userspace HAL components in Python.
    This includes pins and parameters of the various HAL types.
    
    Typical usage:
    
    import hal, time
    h = hal.component("component-name")
    # create pins and parameters with calls to h.newpin and h.newparam
    h.newpin("in", hal.HAL_FLOAT, hal.HAL_IN)
    h.newpin("out", hal.HAL_FLOAT, hal.HAL_OUT)
    h.ready() # mark the component as 'ready'
    
    try:
        while 1:
            # act on changed input pins; update values on output pins
            time.sleep(1)
            h['out'] = h['in']
    except KeyboardInterrupt: pass
    
    When the component is requested to exit with 'halcmd unload', a
    KeyboardInterrupt exception will be raised.

DATA
    HAL_BIT = 1
    HAL_FLOAT = 2
    HAL_IN = 16
    HAL_IO = 48
    HAL_OUT = 32
    HAL_RO = 64
    HAL_RW = 192
    HAL_S32 = 3
    HAL_U32 = 4

Methods defined here:
       exit(...)
           Call hal_exit
       
       getprefix(...)
           Get the prefix for newly created pins and parameters
       
       newparam(...)
           Create a new parameter
       
       newpin(...)
           Create a new pin
       
       ready(...)
           Call hal_ready
       
       setprefix(...)
           Set the prefix for newly created pins and parameters
       
FUNCTIONS
    component_exists(...)
        Return a TRUE value if the named component exists
    
    pin_has_writer(...)
        Return a FALSE value if a pin has no writers and TRUE if it does


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Last edited January 27, 2010 9:48 pm by Chris M (diff)
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