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..
MicroPython license information
===============================
The MIT License (MIT)
Copyright (c) 2013-2017 Damien P. George, and others
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
utime
*****
.. py:module:: utime
The ``utime`` module provides functions for getting the current time and date,
measuring time intervals, and for delays.
.. note::
The ``utime`` module is a MicroPython implementation of the standard Python
``time`` module. It can be imported using both ``import utime`` and
``import time``, but the module is the same.
Functions
=========
.. method:: utime.sleep(seconds)
Sleep for the given number of seconds. You can use a floating-point number
to sleep for a fractional number of seconds, or use the
:func:`utime.sleep_ms()` and :func:`utime.sleep_us()` functions.
.. method:: utime.sleep_ms(ms)
Delay for given number of milliseconds, should be positive or 0.
.. method:: utime.sleep_us(us)
Delay for given number of microseconds, should be positive or 0.
.. method:: utime.ticks_ms()
Returns an increasing millisecond counter with an arbitrary reference point,
that wraps around after some value.
.. method:: utime.ticks_us()
Just like :func:`utime.ticks_ms()` above, but in microseconds.
.. method:: utime.ticks_add(ticks, delta)
Offset ticks value by a given number, which can be either positive or
negative. Given a ticks value, this function allows to calculate ticks
value delta ticks before or after it, following modular-arithmetic
definition of tick values.
Example:
.. code-block:: python
# Find out what ticks value there was 100ms ago
print(ticks_add(time.ticks_ms(), -100))
# Calculate deadline for operation and test for it
deadline = ticks_add(time.ticks_ms(), 200)
while ticks_diff(deadline, time.ticks_ms()) > 0:
do_a_little_of_something()
# Find out TICKS_MAX used by this port
print(ticks_add(0, -1))
.. method:: utime.ticks_diff(ticks1, ticks2)
Measure ticks difference between values returned from
:func:`utime.ticks_ms()` or :func:`ticks_us()` functions, as a signed value
which may wrap around.
The argument order is the same as for subtraction operator,
``ticks_diff(ticks1, ticks2)`` has the same meaning as ``ticks1 - ticks2``.
:func:`utime.ticks_diff()` is designed to accommodate various usage
patterns, among them:
Polling with timeout. In this case, the order of events is known, and you
will deal only with positive results of :func:`utime.ticks_diff()`:
.. code-block:: python
# Wait for GPIO pin to be asserted, but at most 500us
start = time.ticks_us()
while pin.value() == 0:
if time.ticks_diff(time.ticks_us(), start) > 500:
raise TimeoutError
Scheduling events. In this case, :func:`utime.ticks_diff()` result may be
negative if an event is overdue:
.. code-block:: python
# This code snippet is not optimized
now = time.ticks_ms()
scheduled_time = task.scheduled_time()
if ticks_diff(scheduled_time, now) > 0:
print("Too early, let's nap")
sleep_ms(ticks_diff(scheduled_time, now))
task.run()
elif ticks_diff(scheduled_time, now) == 0:
print("Right at time!")
task.run()
elif ticks_diff(scheduled_time, now) < 0:
print("Oops, running late, tell task to run faster!")
task.run(run_faster=true)
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