diff options
| -rw-r--r-- | docs/pyboard/tutorial/amp_skin.rst | 28 |
1 files changed, 27 insertions, 1 deletions
diff --git a/docs/pyboard/tutorial/amp_skin.rst b/docs/pyboard/tutorial/amp_skin.rst index 64f139bb7e..697637f9d2 100644 --- a/docs/pyboard/tutorial/amp_skin.rst +++ b/docs/pyboard/tutorial/amp_skin.rst @@ -69,4 +69,30 @@ Then you can do:: >>> f = wave.open('test.wav') >>> dac.write_timed(f.readframes(f.getnframes()), f.getframerate()) -This should play the WAV file. +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. |