Class Pin – control I/O pins

Pin objects are used to control I / O pins (also known as GPIO-general purpose input / output). Pin objects are usually associated with physical pins that can drive the output voltage and read the input voltage. The pin class has a method to set the pin mode (IN, OUT, etc.) and a method to obtain and set the digital logic level. For analog control of pins, please refer to ADC class.

Construct a pin object by using an identifier that explicitly specifies a certain I/O pin. The allowed identifier form and the physical pin to which the identifier is mapped are port-specific。 The possibility of the identifier is an integer, a string or a tuple with port and pin number.

Example:

from machine import Pin

# create an output pin on pin #32
p0 = Pin(32, Pin.OUT)

# set the value low then high
p0.value(0)
p0.value(1)

# create an input pin on pin #33, with a pull up resistor
p2 = Pin(33, Pin.IN, Pin.PULL_UP)


# configure an irq callback
p2.irq(trigger=Pin.IRQ_FALLING, handler=lambda t:print("IRQ"))

Build Object

class Pin.Pin(id, mode=1, pull=1, value, drive, alt)

Access the pin peripheral (GPIO pin) id associated with the given. If other parameters are given in the build object, they are used to initialize the pins. Any settings not specified will maintain their previous state.

Attention

The mPython control board provides its own pin mapping, mapping pins to GPIO of ESP32.For example, the P0 pin of the control board corresponds to the IO33 of ESP32, then you can use Pin.P0 to replace 33 .

Parameter:

  • id is mandatory and can be any object. Possible value types include：int (Internal pin identifier), str（Pin name）and tuple（[port，pin] match）. If you use mPython, you can use Pin.P(0~20), for example (Pin.P0)P0 pin provides mapping as GPIO.
  • mode specifies the pin mode, which can be one of the following：
    • Pin.IN - Pin is configured as input. If it is regarded as an output, the pin is in a high-impedance state.
    • Pin.OUT - Pin is configured as (normal) output.
    • Pin.OPEN_DRAIN - Pin is configured as an open-drain output. The open-drain output works in the following way：If the output value is set to 0, the pin is active low; if the output value is 1, the pin is high impedance. Not all ports implement this mode, or some ports may only be implemented on certain pins.
    • Pin.ALT_OPEN_DRAIN - Pin configuration as open drain。

pull specifies whether a (weak) pull resistor is connected to the pin, which can be one of the following：

  • None - No pull-up or pull-down resistors
  • Pin.PULL_UP - Pull-up resistor enabled
  • Pin.PULL_DOWN - Pull-down resistor enabled
  • value is only valid for Pin.OUT and Pin.OPEN_DRAIN modes, and specifies the initial output pin value, otherwise the state of the pin peripherals remains unchanged.

Method

Pin.init(mode=1, pull=1, value, drive, alt)

Reinitialize the pin with the given parameters. Only set the specified parameters. The rest of the pin peripheral state will remain unchanged. For detailed information about the parameters, see the build object documentation.

Return None.

Pin.value([x])

This method allows setting and getting the value of the pin, depending on whether x provides the parameter.

If this parameter is omitted, the method obtains the digital logic level of the pin and returns 0 or 1 corresponding to the low voltage signal and the high voltage signal, respectively. The behavior of this method depends on the mode of the pin：

  • Pin.IN - This method returns the actual input value currently present on the pin.
  • Pin.OUT - This method returns the actual input value currently present on the pin.
  • Pin.OPEN_DRAIN - If the pin is in state “0”, the behavior and return value of the method are undefined. Otherwise, if the pin is in state “1”, the method returns the actual input value currently present on the pin.

If parameters are provided, this method sets the digital logic level of the pin. Parameter x can be any value converted to Boolean. If converted to True, set the pin to state “1”, otherwise set it to “0” state. The behavior of this method depends on the mode of the pin：

  • Pin.IN - This value is stored in the output buffer of the pin. The state of the pin will not change, it is still in a high impedance state. Once changed to Pin.OUT or Pin.OPEN_DRAIN mode, the stored value will be activated on the pin.
  • Pin.OUT - The output buffer is immediately set to the given value.
  • Pin.OPEN_DRAIN - If the value is “0”,the pin is set to a low voltage state. Otherwise, the pin is set to high impedance.

When setting the value returned by this method None.

Pin.__call__([x])

Pin object is callable. The call method provides a (quick) shortcut to set and get the value of the pin. It is equivalent to Pin.value([x]). For details, see Pin.value() 。

Pin.on()

Set the pin to high level

Pin.off()

Set the pin to low level

Pin.irq(handler=None, trigger=(Pin.IRQ_FALLING | Pin.IRQ_RISING), wake=None)

Configure the interrupt handler to be called when the trigger source of the pin is active. If the pin mode is Pin.IN, then the trigger source is the external value on the pin. If the pin mode is Pin.OUT, then the trigger source is the output buffer of the pin. Otherwise, if the pin mode is Pin.OPEN_DRAIN, then the trigger source is the output buffer of state ‘0’ and the external pin value of state ‘1’.

Parameter:

  • handler is an optional function that is called when the interrupt is triggered.

  • trigger configure events that can trigger an interrupt. Possible values are：

    • Pin.IRQ_FALLING falling interruption
    • Pin.IRQ_RISING rising interruption
    • Pin.IRQ_LOW_LEVEL low level interruption
    • Pin.IRQ_HIGH_LEVEL high level interruption
    • Pin.WAKE_HIGH Used for wake-up function, high level trigger
    • Pin.WAKE_LOW Used for wake-up function, low level trigger

    These values can be used to perform OR operations together to trigger multiple events.

  • wake select this interrupt to wake up the power mode of the system. It can be machine.IDLE ，machine.SLEEP or machine.DEEPSLEEP . These values can also be “or” calculated together to cause pins to break in multiple power consumption modes.

This method returns a callback object.

Constant

The board’s own pin mapping maps of the mPython Board pins to the GPIO of ESP32 mPython

Pin.P0
Pin.P1
Pin.P2
Pin.P3
Pin.P4
Pin.P5
Pin.P6
Pin.P7
Pin.P8
Pin.P9
Pin.P10
Pin.P11
Pin.P13
Pin.P14
Pin.P15
Pin.P16
Pin.P19
Pin.P20
Pin.P23
Pin.P24
Pin.P25
Pin.P26
Pin.P27
Pin.P28

The following constants are used to configure pin objects.

Pin.IN
Pin.OUT
Pin.OPEN_DRAIN

Select pin mode.

Pin.PULL_UP
Pin.PULL_DOWN
Pin.PULL_HOLD

Select whether there is a pull-up / pull-down resistor. Use None value.

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

Select IRQ trigger type.