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docs/library/pyb.Timer: Document how to use BKIN pin with example. 

Document how to connect the Timer block BRK_IN to a physical Pin alternate
function.

Add an example of PWM Motor drive using complementary outputs with dead
time and break input to kill the PWM and generate a callback.

Signed-off-by: Chris Mason <c.mason@inchipdesign.com.au>
This commit is contained in:
chrismas9 2022-06-26 23:54:37 +10:00 committed by Damien George
parent 33ea400ce8
commit c038ea0cc6
1 changed files with 14 additions and 1 deletions
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15
docs/library/pyb.Timer.rst
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@ -111,7 +111,9 @@ Methods
the PWM when the ``BRK_IN`` input is asserted. The value of this the PWM when the ``BRK_IN`` input is asserted. The value of this
argument determines if break is enabled and what the polarity is, and argument determines if break is enabled and what the polarity is, and
can be one of ``Timer.BRK_OFF``, ``Timer.BRK_LOW`` or can be one of ``Timer.BRK_OFF``, ``Timer.BRK_LOW`` or
``Timer.BRK_HIGH``. ``Timer.BRK_HIGH``. To select the ``BRK_IN`` pin construct a Pin object with
``mode=Pin.ALT, alt=Pin.AFn_TIMx``. The pin's GPIO input features are
available in alt mode - ``pull=`` , ``value()`` and ``irq()``.
You must either specify freq or both of period and prescaler. You must either specify freq or both of period and prescaler.
@ -204,6 +206,17 @@ Methods
ch2 = timer.channel(2, pyb.Timer.PWM, pin=pyb.Pin.board.X2, pulse_width=8000) ch2 = timer.channel(2, pyb.Timer.PWM, pin=pyb.Pin.board.X2, pulse_width=8000)
ch3 = timer.channel(3, pyb.Timer.PWM, pin=pyb.Pin.board.X3, pulse_width=16000) ch3 = timer.channel(3, pyb.Timer.PWM, pin=pyb.Pin.board.X3, pulse_width=16000)
PWM Motor Example with complementary outputs, dead time, break input and break callback::
from pyb import Timer
from machine import Pin # machine.Pin supports alt mode and irq on the same pin.
pin_t8_1 = Pin(Pin.board.Y1, mode=Pin.ALT, af=Pin.AF3_TIM8) # Pin PC6, TIM8_CH1
pin_t8_1n = Pin(Pin.board.X8, mode=Pin.ALT, af=Pin.AF3_TIM8) # Pin PA7, TIM8_CH1N
pin_bkin = Pin(Pin.board.X7, mode=Pin.ALT, af=Pin.AF3_TIM8) # Pin PA6, TIM8_BKIN
pin_bkin.irq(handler=break_callabck, trigger=Pin.IRQ_FALLING)
timer = pyb.Timer(8, freq=1000, deadtime=1008, brk=Timer.BRK_LOW)
ch1 = timer.channel(1, pyb.Timer.PWM, pulse_width_percent=30)
.. method:: Timer.counter([value]) .. method:: Timer.counter([value])
Get or set the timer counter. Get or set the timer counter.