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Old 7th March 2005, 12:28 AM   #1
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Default Ad1940

Is anyone working on SigmaDSP AD1940 and SigmaStudio 2.0?

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Old 19th December 2006, 06:43 AM   #2
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Yes, I have used the AD1940 and Sigma Studio.

The software suite is poorly documented, but once you get past that it is pretty easy to use.

The AD1940 is easy to use, simple I/O. Some of the registers take a bit of getting used to programming as does generating the 5.23 data.

I have built a DSP based active crossover that uses the AD1939 codec, and AD1940 DSP. It does stereo in, and four stereo bands out. 1st, 2nd and 4th order XO, with time delay on all channels. Coding the DSP in signa studio was a doddle.

Writing the software to calculate coefficients to allow the user to program XO freqs etc in real time was less of a doddle, but not that bad.

If you want more details, email me at I have a PCB and a PIC micro program that acts as the boot loader for the DSP if you are interested.
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Old 16th January 2007, 09:48 AM   #3
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Default SigmaDSP


I have deceloped custom flow for Home theatre and cinema theatre decoder.

My SigmaDSP software did not come bundled with the ADI algorithms for Surround and Virtual Speakers.

I need the same for comparing the outputs.

Kindly share the same if you have it.

Thanks and regards,

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Old 16th March 2008, 04:17 AM   #4
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Default SigmaDSP w/ ADAU1701

I am interested in building a plate amp w/ DSP for Biamped studio monitors. I have the demo version of SigmaStudio and would like to avoid buying the evaluation board if possible. Has anyone tryed using SigmaStudio with there own USB to I2C interface? DLP Design makes a development board that uses the same FTD USB chip and also has the same PIC MCU in a very similar circuit. I am assuming that the PIC is just doing RS232 to I2C conversion, but that is just an assumption. Any one have any experience with a similar setup?
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Old 16th March 2008, 11:49 PM   #5
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What you are thinking of should be fairly easy - given a couple of proviso's:
-1- You need to be able to write a bunck of data to a range of addresses in the DSP chip (assuming it uses a similar architecture to the AD1940, which I expect is reasonable given the DSP coding that Sigma Studio does).

A consequence of this is that you will be making a number of transfers of data to the DSP chip. Whatever software you use on the PC needs to support this.

Additionally, if you want to tweak parameters in "real time" then the software will need to understand the data and addressing structure for the DSP.

This is not actually that big a deal, as there are not an awful lot of registers you need to "talk to". I guess the reason I raise it is that there will be time and effort required to get this written, then debugged. (The documentation is not earth shatteringly complete for these DSPs!)

The Sigma Studio software has this built in, but it expects to find the USB to I2C interface they supply with the development system. There is no documentation on this interface at all.

If you COULD use the Analog Devices GUI to drive a third party USB to I2C board then that would be great, as you won't need to write the PC application.

It is a long time since I used the AD board, but it does have features like multilpe memories for storing (on the USB to I2C board) copies of the code, allowing auto loading without the PC being present. This suggests to me that the board is not a straight-through USB to I2C converter. Watch out for this if you go for a third party converter.

-2- In the end, I would expect that you will want to build an offboard boot loader for the DSP anyway.

The one I did uses (well there are 2 now) originally PIC16F877, then once that ran out of room I moved to a PIC18F4520.

Because I am lazy, I simply embed the AD1940 code in a header file for the PIC program, and the PIC writes this to the DSP over an I2C bus.

This has the downside that fiddling with the AD code requires it to be compiled and written to the PIC first.

Here is the odd part though - with the AD Sigma series DSPs, you are very much less likely to be fiddling with the actual DSP code itself, than with the IIR filter parameters.

The consequence of this is that you will not likely be wanting to change the actual DSP code. You will be updating the coefficient memory - which your PIC micro can calculate for itself.

Anyway, that is a couple of random thoughts on the topic!!!

If you want help with (2) feel free to drop me an email.
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Old 9th November 2008, 07:34 PM   #6
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I tried using this:

To conect to sigma studio, I have no idea how to do it >.< Im gonna build the ADAU1701 system and feed the I2C to it using that module. How do i get sigma studio to recognise it?

Is it possible???
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Old 10th November 2008, 04:28 AM   #7
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I am not sure that Sigme Studio would recognise the ADUA1701 if it were interfaced using this USB adapter. The reason is that sigma studio seems to look for the development system - which is a custom USB, memory and SPI interface board.

Then again, why would you want to use Sigma Studio? It is great to develop the DSP code, but once developed surely you would want an interface specific to your application.

In this case you would use Sigma Studio to generate the DSP code, and then write an application on the PC that:
-1- Loads the code generated by Sigma Studio (it is generated when you compile the application)
-2- Configures the DSP registers,
-3- Provides a GUI to the user, and updates the DSP registers.

This would be really easy using the interface board you indicated, as the ADIA1701 is controlled simply by writing and reading from the USB port.

I don't know if you have played with sigma studio, but it is a totally generic development tool, and would be really cumbersome for any "normal user". (even for a tecchie, there are too many cnotrols that could easily mess up the behaviour of the ADUA1701, and possibly mess with your speakers!!!)

So personally I would probably not worry about trying to trick sigma studio into thinking the USB converter is the deevlopment system - I would just get in there and write the app.
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Old 2nd July 2009, 04:49 PM   #8
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Hello! Excuse me for my bad English, I from Russia.

Now I am engaged in the version of the digital filter on AD1940. I the lamer in this area also would like to look at schemes of your product for the approximate sample. I will use the components (DIR1703 as SPDIF receiver, PCM1798 as DAC), simply wished to look at system topology: as it is better to connect AD1940, what components to use for AD1940, in what modes it is better to use AD1940. I will try to write the program independently.
I have a question to you: whether will consult AD1940 with 3 band a stereo the filter (6 speakers), 4 parametric equalizers for middle and high frequencies, 2 reject filters and blocks of a delay for middle speakers and tweters? Or it is necessary to divide the project on two AD1940 (the left channel / the right channel)
I want the scheme and pcb your project.

Once again I am sorry for my English!
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Old 3rd July 2009, 09:35 AM   #9
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GoFren DIY
If I understand what you wish to do, I would say that the AD1940 will fit the processing you want easily into a single device.

My processor is four band stereo, with:
- fourth order crossovers
- DC block
- two parametrics per band
- CD hord compensation for each band (it was easier that way)
- Delays for each band (the delay does not use DSP resources)

From memory there is about 50% resources spare (except delay).

I will try to remember to email you the schematics and stuff.
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