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Modifying saved config in an existing system

Category: Hardware
Product Number: ADAU1701

Hi,

I'm looking at putting some active power amp modules into some of my passive loudspeaker systems.

I've been able to track down some suitable "complete build" modules that should simply drop in to the cabinets. However, the pre-programmed EQ and crossover curves are unsuitable for my speakers/cabinets and I wish to change them.

The manufacturer of the modules has not been helpful so I thought that since the processor is made by AD, I might be able to change things myself.

Since the ADAU1701 processor is already on the main circuit board, is there a way to make a small modification that will allow me communication access so that I can change these parameters? I've been looking through the SigmaStudio software but at first glance there does not seem to be a way to dump the config out so that I can make a change and put it back.

Has anyone done this? If so, how did you configure an interface to communicate with the device and is is possible to get the config out to change it since the device is soldered to the existing board?

This seems like something that would be possible to achieve but I don't really know where to start. Can anyone point me in the right direction? Thanks.

  • Hello Gaztech,

    You cannot read the program that is stored in the EEPROM and reconstruct the SigmaStudio program. You have to obtain the actual SigmaStudio program file that is used in the device. I assume that whoever made this is not going to give this to you. 

    This leaves you with the option of trying to reverse engineer the hardware schematic and the SigmaStudio schematic or just go with some other product that is more friendly towards the DIY community. Dayton Audio has been great for that. I personally have taken one of their kits for a passive two-way speaker and built it without the crossover and then used their four channel amplifier with an ADAU1701 to build a bi-amped system. I did also obtain a measurement microphone and software to measure the speakers and designed the crossover to match the speakers. It was a fun project and I intend to detail it eventually on the YouTube channel. 

    Dave T

  • Hi Dave,

    Ah, it's as I suspected. The documentation doesn't seem to specifically state that you can't read the program out but I assumed that this was the case.

    I have zero chance of getting the original file as it is from a Chinese manufacturer. It's bad enough trying to get parts out the Chinese. This would be impossible.

    I'll take your advice and check out the Dayton Audio stuff as from what you are saying it may deal with my problem. It's a real shame I can't use the module I was talking about as it would be perfect for the job if I could change the crossover and EQ characteristics. 

    Many thanks for your insight.

    G>

  • 0
    •  Analog Employees 
    •  Super User 
    in reply to Gaztech

    Hello Gaztech,

    Most of the Dayton Audio stuff is also Chinese made so you usually cannot get the actual schematics but you can get the SigmaStudio files that you can customize to your liking. What modules did you purchase? Is there a link? 

    Dave T

  • Hi Dave,

    Sorry about the delay in getting back to you.

    I was looking at these:

    https://www.ebay.com/itm/334675910772

    We already have a load of the QSC products and it seems that these modules are the actual modules used in the K12 series that we already own.

    It would be great if we could use a module that is tried and tested. I wish to extend the low end and change the crossover point to allow the use of a 15" low end and a larger HF driver (that goes down lower). These modules have the ADU1701 chip on board  so it would be an ideal platform to get this done. I'm wondering now if it would be worthwhile downloading the Dayton Audio files,putting them into SigmaStudio,  modifying the files and then downloading the file to the processor in the module. I'm "assuming" I could do that??

    G>

  • 0
    •  Analog Employees 
    •  Super User 
    in reply to Gaztech

    Hello Gazech,

    These are great looking modules. I see why you would like to use them. The problem is that you would have to know some details about how the hardware is interfaced. It is using GPIO, AUXADCs for things like level controls, options switches and LEDs. I suppose you could experiment with it to learn what is connected to what.  Is there a 10-way header for the USBi inside the unit?

    So it would take some reverse engineering and then you would have to write your own program to run it. This is most likely possible but I really cannot help you reverse engineer someone else's product. 

    Perhaps you could contact the company that builds these to see if they would do a custom run for you? 

    Dave T

  • Hi Dave,

    Switches, pots etc on the board are connected directly to the ADU1701. I managed to get a schematic for the QSC K12 version and it looks identical to these modules. My thoughts are as you say, write a program to run it.

    I'm thinking that I could write a program configuration, then dump it to an external ROM and short the appropriate pins on the processor to read that on boot up instead of its own internal ROM.There's no programming header on the board.

    I think that is the most effective way to do it. That way, I don't need to mess about with trying to get into the chip itself that is on the board. I can use a standard USBi interface board to program the external ROM. I'll need to put a small "piggy-back" board on top of the main board to take the ROM but that might not be too painful. It also gives me a way to try several combinations easily by swapping ROMs with different configs on them.

    I need to get into programming the 1701 first. Not done these before but the software doesn't look like it's a really steep learning curve. 

    Thanks for your help.

    G>

  • 0
    •  Analog Employees 
    •  Super User 
    in reply to Gaztech

    Hello Gaztech,

    You should go to the analog.com main web site and download the AN-1006 which is an App Note for using the USBi. Some of the details in there will be handy for wiring it up. 

    Then you should subscribe and watch some of my videos on my YouTube channel. (84) How to SigmaDSP and SigmaStudio - YouTube

    I need to add a ton more videos and I have been busy over the past few weeks so I have not had the chance to make some new ones but that will change and I will add some more. There is one for a crossover up there. 

    Dave T