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Thread: HADSR with Teensy ?

  1. #1
    Junior Member
    Join Date
    Nov 2019
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    HADSR with Teensy ?

    Hello everyone,

    As part of our synthesizer project, we chose to use the HADSR envellope from https://midisizer.com/5u/dds-ahdsr-for-5u-modulars/
    code source : https://midisizer.files.wordpress.co...7/src_adsr.zip
    (It seems to be a super envellope, very complete, and in addition the code is shared).

    Problem, it must be controllable in "midi".

    To remedy this problem we found 2 solutions:

    The first, modify the code accordingly to establish a serial communication on the pcb between the Teensy and the Atmega

    However for some time, one wonders if it would not be possible that it is the teensy which makes envellope? It would be a lot of advent (less component, and more speed).

    Concretely, to be able to adapt this envellope to a Teensy we must in theory:

    On the Harware plan:
    1- Adapt the 2 CVs in

    2-Put a DAC 10v (or use one of the Teensy 3.3v DACs with an amp)

    On the Software level:

    1-Implementing MIDI (USB)
    2- Modify the code so that some midi message replace the 3 old toggle switch
    3- Change the code again to replace the 4 potentiometers with midi messages.

    Currently we found for all that hardware, for CV IN we found a good shematic

    https://llllllll.co/uploads/default/...ba3d3203a5.PNG

    The teensy 3.6 driver already a DAC 15v 16bit 12 channels (CV VCO 1 and 2, CV cutoff, resonance, ...), we have 2 outputs available, are on the material level I think it's good.

    But I wonder if it's not too much to manage for the Teensy?

    On the circuit the Teensy manages 28 digipots (not at the same time, one by one in SPI), the DAC 12 channels (in SPI), 4 MCP23S17 (SPI), and he listens to the midi messages via USB.

  2. #2
    Junior Member
    Join Date
    Nov 2019
    Posts
    11
    voici un schéma du circuit de enveloppe piloté par un teensy 3.6.

    Le DAC sur le schéma est un DAC8718, 8 channels 16 bits. Sa plage de fonctionnement va jusqu’à 15V.
    https://imgur.com/rUBAsl8

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