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| author | Dan Halbert <halbert@halwitz.org> | 2018-02-27 22:03:52 -0500 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2018-02-27 22:03:52 -0500 |
| commit | 568c04e6afa8016062f685b2198c0209f62827f4 (patch) | |
| tree | d07b76119f715add462983b335797adf64b61249 /docs/wipy/tutorial/timer.rst | |
| parent | 6a2379fd0bfe10017d8abc5c36ef1d470c0d9b27 (diff) | |
| parent | ea633117d01d94e8d56ed94344e4b3e46b4eef03 (diff) | |
Merge pull request #650 from tannewt/merge_2x3.0.0-alpha.2
Merge in commits from 2.x branch.
Diffstat (limited to 'docs/wipy/tutorial/timer.rst')
| -rw-r--r-- | docs/wipy/tutorial/timer.rst | 70 |
1 files changed, 0 insertions, 70 deletions
diff --git a/docs/wipy/tutorial/timer.rst b/docs/wipy/tutorial/timer.rst deleted file mode 100644 index c87ac4495..000000000 --- a/docs/wipy/tutorial/timer.rst +++ /dev/null @@ -1,70 +0,0 @@ -Hardware timers -=============== - -Timers can be used for a great variety of tasks, calling a function periodically, -counting events, and generating a PWM signal are among the most common use cases. -Each timer consists of two 16-bit channels and this channels can be tied together to -form one 32-bit timer. The operating mode needs to be configured per timer, but then -the period (or the frequency) can be independently configured on each channel. -By using the callback method, the timer event can call a Python function. - -Example usage to toggle an LED at a fixed frequency:: - - from machine import Timer - from machine import Pin - led = Pin('GP16', mode=Pin.OUT) # enable GP16 as output to drive the LED - tim = Timer(3) # create a timer object using timer 3 - tim.init(mode=Timer.PERIODIC) # initialize it in periodic mode - tim_ch = tim.channel(Timer.A, freq=5) # configure channel A at a frequency of 5Hz - tim_ch.irq(handler=lambda t:led.toggle(), trigger=Timer.TIMEOUT) # toggle a LED on every cycle of the timer - -Example using named function for the callback:: - - from machine import Timer - from machine import Pin - tim = Timer(1, mode=Timer.PERIODIC, width=32) - tim_a = tim.channel(Timer.A | Timer.B, freq=1) # 1 Hz frequency requires a 32 bit timer - - led = Pin('GP16', mode=Pin.OUT) # enable GP16 as output to drive the LED - - def tick(timer): # we will receive the timer object when being called - global led - led.toggle() # toggle the LED - - tim_a.irq(handler=tick, trigger=Timer.TIMEOUT) # create the interrupt - -Further examples:: - - from machine import Timer - tim1 = Timer(1, mode=Timer.ONE_SHOT) # initialize it in one shot mode - tim2 = Timer(2, mode=Timer.PWM) # initialize it in PWM mode - tim1_ch = tim1.channel(Timer.A, freq=10, polarity=Timer.POSITIVE) # start the event counter with a frequency of 10Hz and triggered by positive edges - tim2_ch = tim2.channel(Timer.B, freq=10000, duty_cycle=5000) # start the PWM on channel B with a 50% duty cycle - tim2_ch.freq(20) # set the frequency (can also get) - tim2_ch.duty_cycle(3010) # set the duty cycle to 30.1% (can also get) - tim2_ch.duty_cycle(3020, Timer.NEGATIVE) # set the duty cycle to 30.2% and change the polarity to negative - tim2_ch.period(2000000) # change the period to 2 seconds - - -Additional constants for Timer class ------------------------------------- - -.. data:: Timer.PWM - - PWM timer operating mode. - -.. data:: Timer.A -.. data:: Timer.B - - Selects the timer channel. Must be ORed (``Timer.A`` | ``Timer.B``) when - using a 32-bit timer. - -.. data:: Timer.POSITIVE -.. data:: Timer.NEGATIVE - - Timer channel polarity selection (only relevant in PWM mode). - -.. data:: Timer.TIMEOUT -.. data:: Timer.MATCH - - Timer channel IRQ triggers. |
