Audio DSP Processor architecture

[shroff_rushi]

I find it tough for understanding DSP Processor architecture..so need your expertise assistance.. I am quite clear in microprocessor concepts.

Looking at some PPTs, web resources.

shroff_rushi@rediffmail.com

 

[shroff_rushi]

DSP processors are special class of processors designed specifically for DSP algorithms and
operations. They are also designed with power and space constraints in mind for portable
devices like mobile phones and PDAs. They give better performance and low latency for DSP
applications as compare to general purpose processors.

The traditional view is that a DSP Processor is a processor optimized for DSP - meaning the
narrow aspects of multiply/accumulates that are aimed at filters and FFTs. I would first
extend that to say that a DSP processes Signals, so typically has good mechanisms for getting
signals on and off chip - and then challenge it to say that DSP is about much more than
multiply/accumulates, so many architectures may be 'DSP including VLIW and those that are
supplemented by hardware co-processors (video DSP chips often have much more hardware co-
processing than software).

To be honest I think the discussion of 'DSP Processors' is a bit pointless now - most DSP is
done by non-traditional DSP chips, and even what is called a 'DSP' may not be a traditional
one (for instance many multi-core video chips do their audio on what is called 'The DSP' but
is in fact a general purpose ARM core renamed for marketing purposes).

I stick with the definition that a DSP is designed to do DSP but would now challenge any
attempt to say that implies a particular architecture or features - it is application-
specific. However some features are commonly found - like two data memories, cache,
multiply/accumulate operations, address generation, extended precision registers, hardware co-
processors, software and hardware parallelism, special I/O provision, power management.

I declare an interest here as I teach the module 'DSP Processors' at the University of
Kingston London in their MSc Embedded Systems:

Much of my introductory session is devoted to discussing your question - to which there is no
ready answer, only an ability to understand what are DSP applications and so to see what
features are needed and hence what a DSP processor for such an application may look like. The
curriculum content for that module looks as follows, which covers some of the areas I think
important:

o DSP applications
o Hardware layers
o Parallel processing
o Multitasking
o System On Chip Media Processor
o DSP cores
o Memory hierarchy
o Development tools and platforms

=================================
Chris Bore
BORES Signal Processing | Kingston University London

After seeing this question I asked an industry expert who surveys DSP markets, and he said
that 90% of the DSP market is for very big SoC devices with multiple cores and lots of
hardware co-processors and I/O. Of the 10%, much is done with microcontrollers (that can now
easily outperform the original specialist DSPs) - either with special DSP features or not. For
example I am this year adopting the Microchip dsPIC as a teaching platform because it is low-
cost, mass market, with a decent development platform and has many classic traditional DSP
features.