限制#

初始化限制类#

使用以下构造函数创建限位开关：

Limit(port)

此构造函数使用一个参数：

范围

描述

port

限位开关连接到的 3 线端口，无论它是 大脑 上的端口，还是 3 线扩展器 上的端口。

必须先创建 Brain 或 3-Wire Expander，然后才能使用 Limit Class 构造函数创建对象。

# Create the Brain.
brain = Brain()
# Construct a Limit Switch "limit" with the Limit class.
limit = Limit(brain.three_wire_port.a)

This limit object will be used in all subsequent examples throughout this API documentation when referring to Limit class methods.

类方法#

pressed()#

The pressed(callback, arg) method registers a callback function for when the Limit Switch is pressed.

参数

描述

打回来

按下限位开关时调用的回调函数。

arg

**可选。**传递给回调函数的参数元组。

**返回：**无。

# Define a function switch_pressed().
def switch_pressed():
    # The Brain will print that the Limit Switch was pressed 
    # on the Brain's screen.
    brain.screen.print("switch pressed")
# Run switch_pressed when the Limit Switch is pressed.
limit.pressed(switch_pressed)

released()#

The released(callback, arg) method registers a callback function for when the Limit Switch is released.

参数

描述

打回来

当限位开关被释放时调用的回调函数。

arg

**可选。**传递给回调函数的参数元组。

**返回：**无。

# Define a function switch_released().
def switch_released():
    # The Brain will print that the Limit Switch was released
    # on the Brain's screen.
    brain.screen.print("switch released") 
# Run switch_released when the Limit Switch is released.
limit.released(switch_released)

pressing()#

The pressing() method checks if the Limit Switch is currently being pressed.

Returns: True if the Limit Switch is currently being pressed. False if it is not.

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