class Pin – control I/O pins

A pin is the basic object to control I/O pins (also known as GPIO - general-purpose input/output). It has methods to set the mode of the pin (input, output, etc) and methods to get and set the digital logic level. For analog control of a pin, see the ADC class.

Usage Model:

from machine import Pin

# create an output pin on GPIO0
p0 = Pin(0, Pin.OUT)
p0.value(0)
p0.value(1)

# create an input pin on GPIO2
p2 = Pin(2, Pin.IN, Pin.PULL_UP)
print(p2.value())

Constructors

class machine.Pin(id, ...)

Create a new Pin object associated with the id. If additional arguments are given, they are used to initialise the pin. See Pin.init().

Methods

Pin.init(mode, pull=None, *, value)

Initialise the pin:

  • mode can be one of:

    • Pin.IN - input pin.
    • Pin.OUT - output pin in push-pull mode.

  • pull can be one of:

    • None - no pull up or down resistor.
    • Pin.PULL_UP - pull up resistor enabled.

  • if value is given then it is the output value to set the pin if it is in output mode.

Pin.value([value])

Get or set the digital logic level of the pin:

  • With no argument, return 0 or 1 depending on the logic level of the pin.
  • With value given, set the logic level of the pin. value can be anything that converts to a boolean. If it converts to True, the pin is set high, otherwise it is set low.
Pin.__call__([value])

Pin objects are callable. The call method provides a (fast) shortcut to set and get the value of the pin. See Pin.value() for more details.

Pin.alt_list()

Returns a list of the alternate functions supported by the pin. List items are a tuple of the form: ('ALT_FUN_NAME', ALT_FUN_INDEX)

Availability: WiPy.

Pin.irq(*, trigger, handler=None)

Create a callback to be triggered when the input level at the pin changes.

  • trigger configures the pin level which can generate an interrupt. Possible values are:

    • Pin.IRQ_FALLING interrupt on falling edge.
    • Pin.IRQ_RISING interrupt on rising edge.

    The values can be OR’ed together to trigger on multiple events.

  • handler is an optional function to be called when the interrupt triggers.

Returns a callback object.

Attributes

class Pin.board

Contains all Pin objects supported by the board. Examples:

Pin.board.GP25
led = Pin(Pin.board.GP25, mode=Pin.OUT)
Pin.board.GP2.alt_list()

Availability: WiPy.

Constants

The following constants are used to configure the pin objects. Note that not all constants are available on all ports.

Pin.IN
Pin.OUT
Pin.OPEN_DRAIN
Pin.ALT
Pin.ALT_OPEN_DRAIN

Selects the pin mode.

Pin.PULL_UP
Pin.PULL_DOWN

Selects the whether there is a pull up/down resistor.

Pin.LOW_POWER
Pin.MED_POWER
Pin.HIGH_POWER

Selects the pin drive strength.

Pin.IRQ_FALLING
Pin.IRQ_RISING
Pin.IRQ_LOW_LEVEL
Pin.IRQ_HIGH_LEVEL

Selects the IRQ trigger type.