76 lines
2.2 KiB
ReStructuredText
76 lines
2.2 KiB
ReStructuredText
class RTC -- real time clock
|
|
============================
|
|
|
|
The RTC is and independent clock that keeps track of the date
|
|
and time.
|
|
|
|
Example usage::
|
|
|
|
rtc = pyb.RTC()
|
|
rtc.datetime((2014, 5, 1, 4, 13, 0, 0, 0))
|
|
print(rtc.datetime())
|
|
|
|
|
|
Constructors
|
|
------------
|
|
|
|
.. class:: pyb.RTC()
|
|
|
|
Create an RTC object.
|
|
|
|
|
|
Methods
|
|
-------
|
|
|
|
.. 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)
|
|
|
|
``weekday`` is 1-7 for Monday through Sunday.
|
|
|
|
``subseconds`` counts down from 255 to 0
|
|
|
|
.. method:: rtc.wakeup(timeout, callback=None)
|
|
|
|
Set the RTC wakeup timer to trigger repeatedly at every ``timeout``
|
|
milliseconds. This trigger can wake the pyboard from both the sleep
|
|
states: :meth:`pyb.stop` and :meth:`pyb.standby`.
|
|
|
|
If ``timeout`` is ``None`` then the wakeup timer is disabled.
|
|
|
|
If ``callback`` is given then it is executed at every trigger of the
|
|
wakeup timer. ``callback`` must take exactly one argument.
|
|
|
|
.. method:: rtc.info()
|
|
|
|
Get information about the startup time and reset source.
|
|
|
|
- The lower 0xffff are the number of milliseconds the RTC took to
|
|
start up.
|
|
- Bit 0x10000 is set if a power-on reset occurred.
|
|
- Bit 0x20000 is set if an external reset occurred
|
|
|
|
.. method:: rtc.calibration(cal)
|
|
|
|
Get or set RTC calibration.
|
|
|
|
With no arguments, ``calibration()`` returns the current calibration
|
|
value, which is an integer in the range [-511 : 512]. With one
|
|
argument it sets the RTC calibration.
|
|
|
|
The RTC Smooth Calibration mechanism addjusts the RTC clock rate by
|
|
adding or subtracting the given number of ticks from the 32768 Hz
|
|
clock over a 32 second period (corresponding to 2^20 clock ticks.)
|
|
Each tick added will speed up the clock by 1 part in 2^20, or 0.954
|
|
ppm; likewise the RTC clock it slowed by negative values. The
|
|
usable calibration range is:
|
|
(-511 * 0.954) ~= -487.5 ppm up to (512 * 0.954) ~= 488.5 ppm
|