8 thoughts on “Welcome”

    1. The approach described in these pages is to directly control the DSP with the micro in real time. This is a much more flexible approach than simply using SigmaStudio to load a self-boot EEPROM. This approach allows much more flexibility in designing the system tools and user interface–this will be clear when the article on ASD is posted. The approach also allows us to use a wide range of hardware, including the $20 Sure ADAU1701 board, the miniDSP board, or custom designs that are available in the download section. Unfortunately, the freeDSP board is hard-wired to use self-boot mode, so this approach is not compatible with the freeDSP board 🙁

  1. I totally welcome and agree about the aim of this collaborative project. I think, the freeDSP project is not a competitor but a good complement. =) It is focused on open DSP hardware and all boards are released with sources in GitHub. They can be easily modified and build by the community to fit your application, e.g. to boot directly to slave mode. There are also several extension boards (additional IOs, amplifiers, …) and more powerful DSP boards coming soon (with ADAU 1452, e.g. the PiDSP for Raspberry Pi stacking). To make boards compatible (e.g. using a standard I2S connector for extension boards) might be a benefit for the whole community. If you like, you could think about contributing your hardware design to the freeDSP repository. This way both projects can benefit from each other.

    During startup, the current freeDSP CLASSIC acts as MASTER on the data bus and loads the memory and register contents from the connected eeprom. After the data is loaded it sets itself to SLAVE mode. Fabian contributed a comprehensive getting started guide on “Serial communication with the freeDSP” using an Arduino example, which is linked in the “Application notes” section of freeDSP.cc. However, the designs are open source and can be copied and modified to suit your needs. =)

    1. The Audiodevelopers effort is not focused on hardware development, although there will be a number of “specialized” hardware designs posted. The primary reason for avoiding hardware kits or other products is that large commercial producers like Sure Electronics can sell a complete ADAU1701 board for $20, and it makes no sense to compete with that. I’ll be posting some DSP designs with integrated amplifiers and some other designs that work well for active speakers, and if somebody wants to take those designs and market them, that’s fine with me.

      It’s true that the Arduino software described on these pages can work with the freeDSP Classic board, as long as the design does not use the write-back feature. See this link for more info: https://ez.analog.com/message/14318#14318

    1. At this point I’m only comfortable with giving code to those who ask personally (send me email). Much of the code was done quickly and it needs another cycle of refactoring before it is something I would want to publish. However, there always seems to be other development efforts that push a code publishing effort down on the priority list. Also, there is a lot of code–I had to switch from a teensyLC as my “go-to” CPU to the teensy3.2, as there is now more than 65K of code. The code that interfaces to the ADAU1701 is relatively small–probably two pages at the most. If that is all you are interested in, send me an email at administrator@audiodevelopers.com with a description of what you are trying to accomplish with the code.
      The code and roadmap for new development efforts and possibly publishing the code are described in this article.

  2. Hi Neil,
    Just in case you’re still interested, the “power-down problem” with the JAB3 boards made by Sure seems to have a very easy solution: shorting VIN and RST on the J4 connector is supposed to disable the whole “Signal Level Detection” system.

    They mention it here:


    and here:


    I say “seems” because I just found it, remembered having read your article but I haven’t yet tested it. I will next week.

    Cheers and thank you for all the info that you share here.

    1. I need to get back to that JAB3 project–it’s still got a lot of potential as an easy solution for active 2-way speakers. The “right” solution is easy: just save the state in the EEPROM whenever there is a change from the app. Then, when the ADAU1701 wakes up again, it will load that previous state from EEPROM. The code needs to make sure the EEPROM is written with the Program data, Parameter RAM data and register configuration, using the self-boot format documented in the data sheet. I want to finish this off–just haven’t gotten to it due to too many things going on.

      Having this code could also be useful for the low-cost ADUA1701 modules that have the on-board EEPROM, so it is definitely on my “to-do” list.

      The ability to disable the Signal Level Detection is nice for certain applications–thanks for passing that along.

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