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Need some help selecting a DSP chip to use, some questions

Question asked by justin-zazzi on Jul 2, 2017
Latest reply on Jul 9, 2017 by justin-zazzi

I'm an engineering student and this is my first post.  I'm hoping this is the best place.


I would like to build a DSP with the specifications listed at the bottom of this post.  I have spent some time browsing the SigmaDSP processors and I believe the ADAU1401A will do most of what I want and includes both ADC/DAC, but the ADAU1452 seems much more powerful however I would need to specify and design the ADC/DAC stages as well (I'm not opposed to this, just need to learn how to do that too).  This will be a multipurpose learning project with possible applications as a car audio processor, or a 2.1 processor for a desktop speaker system, or a 4.0 processor for a bluetooth speaker system.  Eventually I will concentrate on selecting a bluetooth module, audio amplifier, power supply and battery charger, but those will be other posts later.


My questions are:

1) Should I concentrate on the two SigmaDSP chips I listed above, or should I also consider something from Blackfin or SHARC or TIGERsharc too?  I read the SHARC chips sometimes have more ram or longer time delay abilities.

2) I assume the SigmaStudio is the best environment to program all of these DSP chips, correct?

3) How much time/effort is involved in using the ADAU1452 chip and building the ADC/DAC sections myself with performance at least comparable to the ADAU1401A?  Is this something I could reasonably do, or is there a lot of circuit-board level finesse that would be difficult to learn quickly?

4) For getting up and running quickly, would it be reasonable to buy a pre-made processor board similar to the Sure Electronics board below?  I assume I can interface directly with the DSP chip and configure it as if I had a demo board from Sigma, but without spending the $500 for one which is way beyond my budget. 

5) If I choose to build an external ADC/DAC section, it seems like I should choose a DSP chip that can supply a clock signal to the external chips, right?

6) Any other good questions I'm not asking?


--- my desired specs below:


Must do:

-2 channel analog input

-4 channel analog output

-each output channel needs multiple custom biquad filters (about 7 or more) and time delay (10ms or more)

-compatible with consumer home and automotive environments

-easy to connect to a bluetooth module for sound input, and an all-digital signal chain would be ideal

-high emphasis on sound quality in terms of THD, S/N, etc

-at least CD quality input and output resolution and sampling rate

-affordable on a student budget ~ $100 for this entire project and all related external components would be wonderful


Should do:

-digital input pins for changing the preset or signal processing (detecting headphones, detecting the use of certain output channels in use or not, etc)

-digital output pins for controlling things such as transistors, relays, LEDs, etc

-S/PDIF input either built-in or easily added using external circuitry, optical or coaxial

-single-ended and differential analog inputs and outputs (using an external ADC/DAC is ok)

-dynamic processing for limiters, thermal protection, excursion protection, etc

-at least 96khz/24-bit input and output with emphasis on sound quality


Would be nice:

-FIR filtering, possibly tens of thousands of taps

-convolution engine for each output channel

-headphone amplifier

-FFT and frequency-domain operations

-192khz/24-bit input and output with emphasis on sound quality

-digital output S/PDIF coaxial or optical, even if external components are needed