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Get or set the pin hold. You can apply a hold to a pin by passing
True
(or clear it by
passing
False
). When a pin is held, its value cannot be changed by using
Pin.value()
or
Pin.toggle()
until the hold is released. This Can be used to retain the pin state through a
core reset and system reset triggered by watchdog time-out or Deep-sleep events. Only pins
in the RTC power domain can retain their value through deep sleep or reset. These are:
P2,
P3, P4, P6, P8, P9, P10, P13, P14, P15, P16, P17, P18, P19, P20, P21, P22, P23
.
pin.callback(trigger, handler=None, arg=None)
Set a callback to be triggered when the input level at the pin changes.
trigger
is the type of event that triggers the callback. Possible values are:
Pin.IRQ_FALLING interrupt on falling edge.
Pin.IRQ_RISING interrupt on rising edge.
Pin.IRQ_LOW_LEVEL interrupt on low level.
Pin.IRQ_HIGH_LEVEL interrupt on high level.
The values can be OR-ed together, for instance
trigger=Pin.IRQ_FALLING | Pin.IRQ_RISING
handler
is the function to be called when the event happens. This function will receive
one argument. Set
handler
to
None
to disable it.
arg
is an optional argument to pass to the callback. If left empty or set to
None
, the
function will receive the Pin object that triggered it.
Example:
from machine import Pin
def pin_handler (arg) :
print( "got an interrupt in pin %s" % (arg.id()))
p_in = Pin( 'P10' , mode=Pin.IN, pull=Pin.PULL_UP)
p_in.callback(Pin.IRQ_FALLING | Pin.IRQ_RISING, pin_handler)
For more information on how Pycom’s products handle interrupts, see here .
Attributes
class pin.exp_board
Contains all Pin objects supported by the expansion board. Examples:
5.2.1.4 Pin
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