utime - SG Wireless Document Hub

utime

The utime module provides functions for getting the current time and date, measuring time intervals, and for delays.

Time Epoch: SG Wireless is ESP32 port uses standard for POSIX systems epoch of 1970-01-01 00:00:00 UTC.

Maintaining actual calendar date/time

This requires a Real Time Clock (RTC). On systems with underlying OS (including some RTOS), an RTC may be implicit. Setting and maintaining actual calendar time is responsibility of OS/RTOS and is done outside of MicroPython, it just uses OS API to query date/time. On baremetal ports however system time depends on machine.RTC() object. The current calendar time may be set using machine.RTC().datetime(tuple) function, and maintained by following means:

By a backup battery (which may be an additional, optional component for a particular board).
Using networked time protocol (requires setup by a port/user).
Set manually by a user on each power-up (many boards then maintain RTC time across hard resets, though some may require setting it again in such case).

If actual calendar time is not maintained with a system/MicroPython RTC, functions below which require reference to current absolute time may behave not as expected.

Methods

utime.gmtime([secs])

Convert a time expressed in seconds since the Epoch (see above) into an 8-tuple which contains: (year, month, mday, hour, minute, second, weekday, yearday) If secs is not provided, then the current time from the RTC is used.

year includes the century (for example 2014).
month is 1-12
mday is 1-31
hour is 0-23
minute is 0-59
second is 0-59
weekday is 0-6 for Mon-Sun
yearday is 1-366

utime.localtime([secs])

Like gmtime() but converts to local time. If secs is not provided, the current time from the RTC is used.

utime.mktime(time)

This is inverse function of localtime. It’s argument is a full 8-tuple which expresses a time as per localtime. It returns an integer which is the number of seconds since 1970-01-01 00:00:00 UTC.

utime.sleep(seconds)

Sleep for the given number of seconds. seconds can be a floating-point number to sleep for a fractional number of seconds. Note that other MicroPython ports may not accept floating-point argument, for compatibility with them use sleep_ms() and sleep_us() functions.

utime.sleep_ms(ms)

Delay for given number of milliseconds, should be positive or 0.

utime.sleep_us(us)

Delay for given number of microseconds, should be positive or 0

utime.ticks_ms()

Returns uptime, in milliseconds.

utime.ticks_us()

Just like ticks_ms above, but in microseconds.

utime.ticks_cpu()

Same as ticks_us, but faster.

utime.ticks_diff(new, old)

Measure period between consecutive calls to ticks_ms(), ticks_us(), or ticks_cpu(). The value returned by these functions may wrap around at any time, so directly subtracting them is not supported. ticks_diff() should be used instead. “old” value should actually precede “new” value in time, or result is undefined. This function should not be used to measure arbitrarily long periods of time (because ticks_*() functions wrap around and usually would have short period). The expected usage pattern is implementing event polling with timeout:

# 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

utime.time()

Returns the number of seconds, as an integer, since the Epoch, assuming that underlying RTC is set. If an RTC is not set, this function returns number of seconds since power up or reset). If you want to develop portable MicroPython application, you should not rely on this function to provide higher than second precision. If you need higher precision, use ticks_ms() and ticks_us() functions, if you need calendar time, localtime() without an argument is a better choice.

utime.timezone([secs])

Set or get the timezone offset, in seconds. If secs is not provided, it returns the current value.

In MicroPython, time.timezone works the opposite way to Python. In Python, to get the local time, you write local_time = utc - timezone, while in MicroPython it is local_time = utc + timezone.