Forum Rule: Always post complete source code & details to reproduce any issue!
Results 1 to 5 of 5

Thread: Reading line I/o on audio shield

  1. #1
    Junior Member
    Join Date
    Sep 2019
    Posts
    6

    Reading line I/o on audio shield

    I wish to read any line input (using teensy 4.0 £ from the audio shield and then write it either to the line or headphone output or both. Are there any primitive functions in C to do this ? Does a simple program exist to do this in the audio library ?

  2. #2
    Senior Member+ defragster's Avatar
    Join Date
    Feb 2015
    Posts
    9,695
    This page : pjrc.com/teensy/td_libs_Audio.html

    Has link to:
    Teensy Audio Library
    A toolkit for building streaming audio projects, featuring Polyphonic Playback, Recording, Synthesis, Analysis, Effects, Filtering, Mixing, Multiple Simultaneous Inputs & Outputs, and Flexible Internal Signal Routing.
    All audio is CD quality (16 bits, 44.1 kHz) and streams automatically as your Arduino Sketch Runs
    Tutorial

    Tutorial examples from this video are available in Arduino, from File > Examples > Audio > Tutorial.
    Design Tool
    Audio System Design Tool

  3. #3
    Senior Member+ defragster's Avatar
    Join Date
    Feb 2015
    Posts
    9,695
    Was the second post - a duplicate post - or asking a different question?:
    Access to analog input and headphones
    Are there primitive functions in the audio lib (or outside it) which will allow me to read single 16 bit values from the line inputs of the audio shield into the Teensy 4.0 and also the complementary...

  4. #4
    Junior Member
    Join Date
    Sep 2019
    Posts
    6
    Thanks defragster, Yes. I think thatís the way forward for me. I dismissed the tutorial previously, as being trivial and not the way I need to process my guitar project, however I can see that if I set up a design which uses io to the audio board then I can export that design onto a blank sketch and pick out from it the relevant function calls for my standalone use.
    I already have the project irunning on a Due (FFT not fast enough 22mS) also the io on the Due is poor and Iím hoping that the io on the Teensy shield is cd quality as advertised ?
    Certainly the Teensy 4.0 processor is incredibly powerful - I can do a 256 point FFT in 124 uS.

  5. #5
    Junior Member
    Join Date
    Sep 2019
    Posts
    6
    Fragster. Thanks for your help. I have all the new components purchased for the Teensy 4 + Audio. Have been using the GUI tool and reading the documentation on the Audio chip itself but cannot find a hook to where the audio samples arrive from the line ADC and to where they are dispatched to the DAC.
    It appears that they fill a buffer by DMA. Is that so? Can you pinpoint a place where I can collect a 16 bit sample and, once processed, deposit it.
    Thanks , Brian Fish

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •