diff options
| -rw-r--r-- | docs/rp2/quickref.rst | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/docs/rp2/quickref.rst b/docs/rp2/quickref.rst index 23071d7721..ec31442990 100644 --- a/docs/rp2/quickref.rst +++ b/docs/rp2/quickref.rst @@ -135,6 +135,12 @@ Use the :mod:`machine.Timer` class:: tim = Timer(period=5000, mode=Timer.ONE_SHOT, callback=lambda t:print(1)) tim.init(period=2000, mode=Timer.PERIODIC, callback=lambda t:print(2)) +By default, timer callbacks run as soft IRQs so they can allocate but +are prone to GC jitter and delays. Pass ``hard=True`` to the ``Timer()`` +constructor or ``init()`` method to run the callback in hard-IRQ context +instead. This reduces delay and jitter, but see :ref:`isr_rules` for the +restrictions that apply to hard-IRQ handlers. + .. _rp2_Pins_and_GPIO: |