Read parallel port input pin from python Handler

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07 Feb 2013 07:52 #29747 by amirhadar
Hi,

I'm trying to understand how to read parallel port general purpose input pin from python glade gui handler class.

I want to write python program that reacts to input pins and perform operations.

Thanks,
Amir Hadar

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07 Feb 2013 20:16 #29758 by amirhadar
Hi,
I found the answer myself. I guess its a newbie question.

Two ways to do it:

Method One (a bit awkward):
Through using a led in the UI.
Define a HAL_LED on your panel in glade ui designer.
in custom_postgui.hal connect the input signal to the led

net input1 parport.0.pin-12-in-not => gladevcp.hal_led1

You can add signal handler to the led on_hal_led1_hal_pin_changed
Then add the python method to your handler class

Example:
def on_hal_led1_hal_pin_changed(self,hal_led1,data=None):
pin = hal_led1.hal_pin.get()
print "on_hal_led1_hal_pin_changed ",pin

Method Two (the right way):
In python handler file:

Add import:
import hal_glib

in the constructor of the class (__init__) add new pin definition for the panel hal component
# Define new pin with GPin (hal_glib) wrapper.
self.input_plate_pin = hal_glib.GPin(self.halcomp.newpin("input_plate",hal.HAL_BIT, hal.HAL_IN))
# connect the pin to a callback
self.input_plate_pin.connect('value-changed', self.on_input_plate_pin_value_changed)

# The callback itself:
def on_input_plate_pin_value_changed(self,input_plate_pin,data=None):
print "on_input_plate_pin_value_changed",input_plate_pin.get()

In the custom_postgui hal I have connected the input to both the led and the new pin

net input1 parport.0.pin-12-in-not => gladevcp.hal_led1 gladevcp.input_plate

Great Success!!!

Kind Regards,
Amir Hadar

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