This is a preview version of the DisplayLink DL-7450 Software Development Kit Documentation. The functionality that is described and made available in this version is subject to addition, removal or change without warning.

class DigitalOutput – manage a GPIO configured as a digital output

The DigitalOutput class provides an interface for applications to write to a GPIO pin. Applications should not try to create DigitalOutput objects directly, but should use the gpio.create function instead. This function reads the underlying configuration and raises an exception if the named pin does not exist, whereas the DigitalOutput constructor will create a non-functional object.

Constructor

class gpio.DigitalOutput(pin_name, active_high)

The parameters are:

• pin_name the name of the GPIO pin.

• active_high is a boolean value that indicates whether the pin is considered active when it is at the high voltage level. The I/O expanders on the DL-7450 are configured to be active low, that is, the pin is held at the high value by default and pulled down to the low voltage level on activation.

Methods

DigitalOutput.write(val)

Write to the pin. The value must be 1 or 0 to activate or deactivate the pin. Attempting to write any other value will result in a ValueError being raised.

For example:

import gpio
pin = gpio.create("MyLed")
pin.write(1)

DigitalOutput.active_high()

Returns a boolean that is True if the pin is configured to be active in the high state, or False if the pin is configured to be active in the low state.

For example:

import gpio
from wakeup import wakeup

pin = gpio.create("led")

val = 0

def blink():
   global val
   pin.write(val)
   if val == 0:
      val = 1
   else:
      val = 0


wakeup(blink, 0, blink)