Which SigmaDSP Processor for my Application?

Hello,

The ADAU1701 is a popular choice. It can self-boot from an external E2Prom which SigmaStudio can program for you, thus no system microcontroller is needed. You get two analog inputs and four analog outputs. I2S digital audio in / out is also available, but the -1701 has no built-in sample rate converters. The -1701 runs on 3.3V, at about 110 mA. Its SigmaStudio toolbox has a large enough assortment of algorithms satisfy most applications. At a sample rate of 96 KHz, you have about 500 instructions available for your program. To show what this can do for you, the layout below (10 parametric IRR filters and a L-R 48 dB two-way crossover, all in stereo) uses 388 instructions. A FIR algorithm is also available in the toolbox, but you'll have specify your own kernel for each filter, and if your filters get too large you'll run out of the chip's 2 K sample data memory.

You can download SigmaStudio before committing to a particular IC, in order to try out signal flows and see what fits.

Best regards,

Bob

You only have 512 instructions with -1701 at 96kHz, which is pushing it for the number of filters you want. My recommendation would be to write your proposed program in SigmaStudio and see if can be made to fit on -1701. Otherwise, you'll need to use -144x or -145x.

Hello Jon,

Yes you are correct. Although the -1701 has enough room to run the project shown above at 96 K, an attempt to use FIR filters would run out of instructions long before exhausting the data RAM. Thanks for pointing this out.

Mantabernd -- I do like your avatar, of course. Right now, mine is doing what cats do best, sleeping.

Best regards,

Bob

Hello,

thanks a lot for the fast and high quality replies. I will install SigmaStudio and have a look what fits best in my application but I think 1701 will do a good job for a fair price.

KJBob: Thanks Cats are great!