In machine.RTC().datetime(), microseconds are always 0.

[hdragonkr]

Dear MicroPython Community

In machine.RTC().datetime(), microseconds are always 0.
V1.20.0 ~ V1.23.0

MicroPython v1.23.0 on 2024-06-02; Teensy 4.1 with MIMXRT1062DVJ6A

import machine
machine.RTC().datetime()
(2024, 7, 8, 0, 12, 8, 27, 0)

MicroPython v1.19.1 on 2022-06-18; Teensy 4.1 with MIMXRT1062DVJ6A

import machine
machine.RTC().datetime()
(2024, 7, 8, 0, 13, 19, 50, 646668)

Please fix it in the next version.

Thank you for your time and assistance.

[robert-hh]

The support for microseconds was removed because it did not add any additional value to using ticks_us(). The RTC itself does not provide a microsecond value. Instead the counter of ticks_us() was used simulate the RTC µs value. But the RTC and the ticks_us() counter are not synchronized and will have a drift. Usually after a few hours the difference will accumulate to 1 second.

For getting µs time differences, using ticks_us() works better, since the call itself takes way less time.

[hdragonkr]

This feature has been removed.
OK, I will use the ticks_us() instead of the RTC us.

Thanks for your answer.

[Josverl]

Roberts,
would it make sense to update the RTC.datetime docs on this ?

something like:

.. method:: RTC.datetime([datetimetuple])

   Get or set the date and time of the RTC.

   With no arguments, this method returns an 8-tuple with the current
   date and time.  With 1 argument (being an 8-tuple) it sets the date
   and time.

   The 8-tuple has the following format:

       (year, month, day, weekday, hours, minutes, seconds, subseconds)

   -The meaning of the ``subseconds`` field is hardware dependent.
   +In v1.23.0 the support for subseconds was removed because it did not add any additional value to using ticks_us(). 
   +The RTC itself does not provide a microsecond value.

[robert-hh]

I could add these works to the open MIMXRT service pack PR.