Class: OrigenLink::Server::Pin

Inherits:
Object
  • Object
show all
Defined in:
lib/origen_link/server/pin.rb

Constant Summary collapse

@@pin_setup = 
{
  in:  'in',
  out: 'out'
}

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(ionumber, direction = :in) ⇒ Pin

initialize:

description - This method will execute system command
              "sudo echo ionumber > /sys/class/gpio/export"
              to create the IO file interface.  It will
              set the direction, initial pin state and initialize
              instance variables
ionumber - required, value indicating the pin number (BCM IO number,
           not the header pin number)
direction - optional, specifies the pin direction.  A pin is
            initialized as an input if a direction isn't specified.



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# File 'lib/origen_link/server/pin.rb', line 27

def initialize(ionumber, direction = :in)
  @ionumber = Integer(ionumber)
  @pin_dir_name = "#{Server.gpio_dir}/gpio#{@ionumber}/direction"
  @pin_val_name = "#{Server.gpio_dir}/gpio#{@ionumber}/value"
  if !File.exist?(@pin_dir_name)
    system("echo #{@ionumber} > #{Server.gpio_dir}/export")
    sleep 0.05
    if $CHILD_STATUS == 0
      @gpio_valid = true
    else
      @gpio_valid = false
    end
  else
    @gpio_valid = true
  end
  if @gpio_valid
    if File.writable?(@pin_dir_name)
      @pin_dir_obj = File.open(@pin_dir_name, 'w')
      update_direction(direction)
    else
      @gpio_valid = false
      puts "#{@pin_dir_name} is not writable. Fix permissions or run as super user."
    end
    @pin_val_obj = File.open(@pin_val_name, 'r+') if @gpio_valid
  end
end

Instance Attribute Details

#gpio_valid ⇒ Object (readonly)

Returns the value of attribute gpio_valid.



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# File 'lib/origen_link/server/pin.rb', line 14

def gpio_valid
  @gpio_valid
end

Instance Method Details

#destroy ⇒ Object 



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# File 'lib/origen_link/server/pin.rb', line 54

def destroy
  if @gpio_valid
    @pin_dir_obj.close
    @pin_val_obj.close
    # system("echo #{@ionumber} > /sys/class/gpio/unexport")

    # puts "pin #{@ionumber} is no longer exported"

  end
end

#in ⇒ Object

in:

description - Reads and returns state of the pin.  If the pin
              is setup as an output, the direction will first
              be changed to input.



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# File 'lib/origen_link/server/pin.rb', line 83

def in
  if @gpio_valid
    if @direction == :out
      update_direction(:in)
    end
    # below is original read - slow to reopen every time

    # File.open(@pin_val_name, 'r') do |file|

    #  file.read#.chomp

    # end

    # end original read

    @pin_val_obj.pos = 0
    @pin_val_obj.getc
  end
end

#out(value) ⇒ Object

out:

description - Sets the output state of the pin.  If the pin
              is setup as an input, the direction will first
              be changed to output.



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# File 'lib/origen_link/server/pin.rb', line 68

def out(value)
  if @gpio_valid
    if @direction == :in
      update_direction(:out)
    end
    @pin_val_obj.write(value)
    @pin_val_obj.flush
  end
end

#to_s ⇒ Object 



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# File 'lib/origen_link/server/pin.rb', line 116

def to_s
  'OrigenLinkPin' + @ionumber.to_s
end

#update_direction(direction) ⇒ Object

update_direction:

  description - Sets the pin direction

direction - specifies the pin direction.  A pin is
            initialized as an input if a direction isn't specified.

Valid direction values:
  :in - input
  :out  -  output



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# File 'lib/origen_link/server/pin.rb', line 107

def update_direction(direction)
  if @gpio_valid
    @pin_dir_obj.pos = 0
    @pin_dir_obj.write(@@pin_setup[direction])
    @pin_dir_obj.flush
    @direction = direction
  end
end