8. utime

MicroPython contains an utime module based upon the time module in the Python standard library.

This module gets measure time intervals and create delays.

8.1. sleep

The standard microbit library has its own sleep method (in millisecs).

utime.sleep may be convenient for micro sleeps or sleeps in seconds.

utime.sleep(seconds): Sleep for the given number of seconds. seconds is an int or float.

utime.sleep_ms(ms): Delay for given number of milliseconds. milliseconds is a positive int or 0.

utime.sleep_us(us): Delay for given number of microseconds. microseconds is a positive int or 0.

The code below has a sleep of 2 seconds between scrolling text.

from microbit import *
import utime

while True:
    display.scroll(".")
    utime.sleep(2)

8.2. ticks

utime.ticks_ms(): Returns an increasing millisecond counter with an arbitrary reference point, that wraps around after some value.

utime.ticks_us(): Returns an increasing microsecond counter with an arbitrary reference point, that wraps around after some value.

To find out wrap value use:

from microbit import *
import utime

# Find out TICKS_MAX used by this port
print(utime.ticks_add(0, -1))

8.3. ticks_add

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 a ticks value, delta ticks before or after it.

Find out TICKS_MAX for the wrapping.

from microbit import *
import utime

# Find out TICKS_MAX
tick_max = utime.ticks_add(0, -1)
print(tick_max)

Use for a deadline:

from microbit import *
import utime

timer = 3000
deadline = utime.ticks_add(utime.ticks_ms(), timer)
while utime.ticks_diff(deadline, utime.ticks_ms()) > 0:
    utime.sleep_ms(200)
display.show(Image.SKULL)

8.4. ticks_diff

utime.ticks_diff(ticks1, ticks2)

Measure ticks difference between values returned from utime.ticks_ms() or 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.

The code below, checks for a change in the pin2 reading for up to 2 seconds, then displays a “TIMEDOUT” message.

from microbit import *
import utime

display.scroll(pin2.read_digital())
start = utime.ticks_ms()
while pin2.read_digital() == 0:
    if utime.ticks_diff(utime.ticks_ms(), start) > 2000:
        display.scroll("TIMEDOUT")