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diff --git a/docs/pyboard/tutorial/amp_skin.rst b/docs/pyboard/tutorial/amp_skin.rst deleted file mode 100644 index 697637f9d..000000000 --- a/docs/pyboard/tutorial/amp_skin.rst +++ /dev/null @@ -1,98 +0,0 @@ -The AMP audio skin -================== - -Soldering and using the AMP audio skin. - -.. image:: img/skin_amp_1.jpg - :alt: AMP skin - :width: 250px - -.. image:: img/skin_amp_2.jpg - :alt: AMP skin - :width: 250px - -The following video shows how to solder the headers, microphone and speaker onto the AMP skin. - -.. raw:: html - - <iframe style="margin-left:3em;" width="560" height="315" src="http://www.youtube.com/embed/fjB1DuZRveo?rel=0" frameborder="0" allowfullscreen></iframe> - -For circuit schematics and datasheets for the components on the skin see :ref:`hardware_index`. - -Example code ------------- - -The AMP skin has a speaker which is connected to ``DAC(1)`` via a small -power amplifier. The volume of the amplifier is controlled by a digital -potentiometer, which is an I2C device with address 46 on the ``IC2(1)`` bus. - -To set the volume, define the following function:: - - import pyb - def volume(val): - pyb.I2C(1, pyb.I2C.MASTER).mem_write(val, 46, 0) - -Then you can do:: - - >>> volume(0) # minimum volume - >>> volume(127) # maximum volume - -To play a sound, use the ``write_timed`` method of the ``DAC`` object. -For example:: - - import math - from pyb import DAC - - # create a buffer containing a sine-wave - buf = bytearray(100) - for i in range(len(buf)): - buf[i] = 128 + int(127 * math.sin(2 * math.pi * i / len(buf))) - - # output the sine-wave at 400Hz - dac = DAC(1) - dac.write_timed(buf, 400 * len(buf), mode=DAC.CIRCULAR) - -You can also play WAV files using the Python ``wave`` module. You can get -the wave module `here <http://micropython.org/resources/examples/wave.py>`__ and you will also need -the chunk module available `here <http://micropython.org/resources/examples/chunk.py>`__. Put these -on your pyboard (either on the flash or the SD card in the top-level directory). You will need an -8-bit WAV file to play, such as `this one <http://micropython.org/resources/examples/test.wav>`_, -or to convert any file you have with the command:: - - avconv -i original.wav -ar 22050 -codec pcm_u8 test.wav - -Then you can do:: - - >>> import wave - >>> from pyb import DAC - >>> dac = DAC(1) - >>> f = wave.open('test.wav') - >>> dac.write_timed(f.readframes(f.getnframes()), f.getframerate()) - -This should play the WAV file. Note that this will read the whole file into RAM -so it has to be small enough to fit in it. - -To play larger wave files you will have to use the micro-SD card to store it. -Also the file must be read and sent to the DAC in small chunks that will fit -the RAM limit of the microcontroller. Here is an example function that can -play 8-bit wave files with up to 16kHz sampling:: - - import wave - from pyb import DAC - from pyb import delay - dac = DAC(1) - - def play(filename): - f = wave.open(filename, 'r') - total_frames = f.getnframes() - framerate = f.getframerate() - - for position in range(0, total_frames, framerate): - f.setpos(position) - dac.write_timed(f.readframes(framerate), framerate) - delay(1000) - -This function reads one second worth of data and sends it to DAC. It then waits -one second and moves the file cursor to the new position to read the next second -of data in the next iteration of the for-loop. It plays one second of audio at -a time every one second. |