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Thread: Teensy - Voltage Control. Which DAC chip?

  1. #1
    Junior Member
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    Teensy - Voltage Control. Which DAC chip?

    Hi guys, I'm new in teensy environment.

    I'm trying to create a Voltage Control with my Teensy.
    I would to creare a DIGITAL control (teensy) in order to control an Analog Circuit .. IE a Synth ecc

    I'd like to use DAC8565 (16bit with 4 ch out), cause i found this chip used with teensy in a Eurorack Module, but i'm surprise about lack of documentation/example/ecc.


    So is there a, alternative, well documented DAC chip that you advise me to check?

    I really apprecciate code example or little project :-)

  2. #2
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    The DAC8565 is not an I2C controlled device. You need to bit bang it with a 24-bit serial stream (pg6). Bet if you looked into the Eurorack Module & its software, you would find the code used to talk to it. Only other DAC I have used was the MCP4728a0, but that is a quad 12-bit unit with I2C.

  3. #3
    Hello,

    I don't know if it fits your requirements, but I have successfully used MCP4726 (12bit, I2C).

    Here is the data sheet of the IC: https://ww1.microchip.com/downloads/...Doc/22272C.pdf

    And here is a library for Arduino (also runs on my teensy project): https://github.com/uChip/MCP47X6

    Have fun

  4. #4
    The DAC8565 is used in the ornament and crime eurorack module. It's simple enough to interface with via SPI and the entire App ecosystem is open source, so a great learning opportunity (albeit complex for a beginner). Keep in mind though that as on the o_C module, you'll need to scale the DAC output voltages to eurorack levels. This is outlined nicely here.

    If you want to experiment with generating CV signals digitally without the analog circuitry to scale voltages, I'd recommend checking out the MAX11300, for which there is a simple Arduino library here. There is a relatively cheap breakout (MAX11300PMB1) available for about 25€ at the usual locations. With this IC you can generate up to 20 CV signals at +-5V or 0-10V if you like.

  5. #5
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    Thank you very much.
    I know O_C module it's my start point inspiration. But i'm new about firmware (not software, Java ecc ecc) and the O_C code source is not clear at all for me. So i tried to found some simplest example about the DAC8565 but without luck.
    DAC8565 would be my first choice course i saw that a lot of eurorack module use this family of product. But I would have more code example. Instead for the MCP i found more documentation. Newbie problem i think.

    I dont know MAX11300 but you description is really interesting cause support . Some Eurorack module or other product use this chip?

    Thanks a lot!!

  6. #6
    Junior Member
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    Thank you very much .. i will try to find out some information about MCP4726.

  7. #7
    Quote Originally Posted by Svenson View Post
    Thank you very much.
    I know O_C module it's my start point inspiration. But i'm new about firmware (not software, Java ecc ecc) and the O_C code source is not clear at all for me. So i tried to found some simplest example about the DAC8565 but without luck.
    DAC8565 would be my first choice course i saw that a lot of eurorack module use this family of product. But I would have more code example. Instead for the MCP i found more documentation. Newbie problem i think.
    As a "newbie", I wouldn't recommend using o_C source code as a starting point for interfacing with the DAC8565. The o_C is designed to generate *precision* CV signals, like V/Oct, where DC accuracy is extremely important. The o_C source is very much optimized, and naturally more complex in order to achieve this. I you really want to use the o_C as a starting point, then just build or buy one! Then you can play with the firmware to familiarize yourself with the concepts, starting from a tested and working foundation.

    Quote Originally Posted by Svenson View Post
    I dont know MAX11300 but you description is really interesting cause support . Some Eurorack module or other product use this chip?
    The Poly2 from Polyend uses the MAX11300, but is not open source.

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