diff options
Diffstat (limited to 'docs/source/lang/api/analogwrite.rst')
| -rw-r--r-- | docs/source/lang/api/analogwrite.rst | 43 |
1 files changed, 23 insertions, 20 deletions
diff --git a/docs/source/lang/api/analogwrite.rst b/docs/source/lang/api/analogwrite.rst index 9147b96..dd2192a 100644 --- a/docs/source/lang/api/analogwrite.rst +++ b/docs/source/lang/api/analogwrite.rst @@ -52,7 +52,7 @@ you much more precise control over the duty cycle of your PWM output. If you're porting code from the Arduino and want a quick-and-dirty fix, one solution is to :ref:`map <lang-map>` the argument to -analogWrite into the right range:: +analogWrite() into the right range:: // Arduino code: analogWrite(pin, duty); @@ -65,14 +65,14 @@ This will convert values in the range 0-255 to values in the range which control PWM output. See the :ref:`timers reference <timers>` for more information. -Another fix is to consult the :ref:`pin mapping mega table -<pin-mapping-mega-table>` to find the timer which controls PWM on the -pin you're using, then set that Timer's overflow to 255. Subsequent -calls to analogWrite() should work as on the Arduino (with the same -loss of precision). Note, however, that that affects the overflow for -the **entire timer**, so other code relying on that timer (such as any -:ref:`interrupts <lang-attachinterrupt>` the timer controls) will -likely need to be modified as well. +Another fix is to consult your board's :ref:`pin maps <gpio-pin-maps>` +to find the timer which controls PWM on the pin you're using, then set +that Timer's overflow to 255. Subsequent calls to analogWrite() +should work as on the Arduino (with the same loss of precision). +Note, however, that that affects the overflow for the **entire +timer**, so other code relying on that timer (such as any +:ref:`interrupts <lang-hardwaretimer-interrupts>` the timer controls) +will likely need to be modified as well. Difference 2: You must use pinMode() to set up PWM ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -140,24 +140,28 @@ If your application definitely requires Arduino's PWM frequency, then the steps are: 1. Figure out which :ref:`timer <lang-hardwaretimer>` controls PWM - output on your pin (\ :ref:`this table <pwm-timer-table>` is your - friend here). Let's say it's ``Timern``\ , where ``n`` is some - number 1, 2, 3, or 4. + output on your pin (\ :ref:`your board's Timer Pin Map + <gpio-pin-maps>` is your friend here). -2. Call ``Timern.setPeriod(2041)``\ . This will set the timer's - period to approximately 2041 microseconds, which is a frequency of - approximately 490 Hz. +2. Let's say it's timer ``n``, where ``n`` is some number. You'll + then need to put "``HardwareTimer timer(n);``" with your variables, + as described in the :ref:`HardwareTimer + <lang-hardwaretimer-getting-started>` reference. + +3. In your :ref:`lang-setup`, put "``timer.setPeriod(2041);``". This + will set the timer's period to approximately 2041 microseconds, + which is a frequency of approximately 490 Hz. Be aware that this will change the period for the **entire timer**\ , and will affect anything else in your program that depends on that timer. The important examples are :ref:`timer interrupts -<lang-hardwaretimer-attachinterrupt>` and :ref:`PWM +<lang-hardwaretimer-interrupts>` and :ref:`PWM <timers-pwm-conflicts>`\ . -See also +See Also -------- -- :ref:`Maple PWM tutorial <pwm>` +- :ref:`pwm` .. rubric:: Footnotes @@ -169,5 +173,4 @@ See also Maple uses 2 bytes of memory, and an unsigned (i.e., nonnegative) integer with size 2 bytes can hold the values between 0 and 65,535. - -.. include:: cc-attribution.txt +.. include:: /arduino-cc-attribution.txt |