Implementing Digital Audio Effects Using a Hardware/Software Co-Design Approach
M. Pfaff, D. Malzner, J. Seifert, J. Traxler, H. Weber, G. Wiendl - Implementing Digital Audio Effects Using a Hardware/Software Co-Design Approach - Digital Audio Effects 2007 - DAFx-07, Bordeaux, France, 2007, pp. 125-132
Digital realtime audio effects as of today are realized in
software in almost all cases. The hardware platforms used
for this purpose reach from multi purpose processors like
the Intel Pentium class over embedded processors (e.g. the
ARM family) to specialized DSP.
The upcoming technology of complete systems on a single
programmable chip contrasts such a software centric solution,
because it combines software and hardware via some
co-design methodology and makes for a promising alternative
for the future of realtime audio. Such systems are able
to combine the vast amount of computing power provided
by dedicated hardware with the flexibility offered by software
in a way the designer is free to influence.
While the main realization vehicles for these systems
FPGAs were already promising but unfortunately offered
limited possibilities a decade ago  they have made rapid
progress over the years being one of the product classes that
drive the silicon technology of tomorrow.
We describe an example for such a realtime digital effects
system which was developed using a hardware/software
co-design method. While digital realtime audio processing
takes place in low latency dedicated hardware units
the control and routing of audio streams is done by software
running on a 32 bit NIOS II softcore processor. Implementation
of the hardware units is done using a DSP centric
methodology for raising the abstraction level of VHDL descriptions
while still making use of standard of the shelf
FPGA synthesis tools. The physical implementation of the
complete system uses a rapid prototyping board tailored for
communications and audio applications based on an Altera
Cyclone II FPGA.