Hello. I've been working on an open source programmable digital effects pedal for about one or 2 months, but I found out something that really destroyed the concept and I had to scrap it. The DSP inside the pedal is the ADAU1701 from Analog Devices, and I liked it really much because it was programmed by dragging and dropping DSP blocks, and I found it to be very user friendly and educational. The thing is that a couple of days ago, I was on an Analog Devices Forum, and I stumbled on a post about a cheap USBi board (USBi is the name of a board sold by Analog Devices which is used to program their SigmaDSP evaluation boards. It is a USB-I2C interface that works (and is the only one supported) with Sigma Studio and it is like $80 USD). In the post, a guy was asking if he could clone the EEPROM inside their USBi to make a cheaper version of it, and another guy from analog devices said that there was no restriction prohibiting him to do that,
BUT he also said
(...)I want to clearly state that SigmaStudio is absolutely not freeware or open source, and it cannot be distributed. You need to obtain it either by purchasing our evaluation hardware or by requesting a key via our email address, and you may not distribute it to the public. SigmaStudio may only be used by system designers, and may not be distributed to end customers using products containing SigmaDSP. In effect, we want to limit SigmaStudio distribution to people who have purchased evaluation hardware, although we do allow people to request it for evaluation as well.
And, well... that really took my project apart...
(it was probably my fault. I should have looked this up first
)
Anyway... I wanted to share my designs with the community in case anyone wants to build it (I have not tested it yet).
It has an FTDI chip to make the conversion between USB and I2C and it is most likely not compatible with Sigma Studio, but you can probably make a program that can load the files from Sigma Studio to the EEPROM. It also has some breakout pins for the General Propose Ports of the DSP chip, a selectable LPF for the inputs and a fixed LPF for the outputs. I wanted it to be as simple as possible at first.
If anyone wants to point out potential and/or obvious design errors in my design, I will thank you very much, since I don't have much experience.
Here is the link for the files (in KiCAD).
https://github.com/DiegoRosales/El_Rockero.git