utime module provides functions for getting the current time and date, measuring time intervals, and for delays.
Time Epoch: Pycom’s ESP32 port uses standard for POSIX systems epoch of
1970-01-01 00:00:00 UTC.
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:
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.
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.
yearincludes the century (for example 2014).
weekdayis 0-6 for Mon-Sun
gmtime() but converts to local time. If
secs is not provided, the current time from the RTC is used.
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.
Sleep for the given number of
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
Delay for given number of milliseconds, should be positive or 0.
Delay for given number of microseconds, should be positive or 0
Returns uptime, in milliseconds.
ticks_ms above, but in microseconds.
ticks_us, but faster.
Measure period between consecutive calls to
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
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_us() functions, if you need calendar time,
localtime() without an argument is a better choice.
Set or get the timezone offset, in seconds. If
secs is not provided, it returns the current value.
time.timezoneworks 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.