How to Make Right Selection Between Fpga and Dsp

EE Times-India | eetindiaDevice Cost Range
FPGA is an electronic device that helps the designMinimum Cents/MMAC for FPGA
engineers to create custom logic for highMinimum Cents/MMAC for DSP
commutation signal processing and DSP is a CPU forHigh (>1000 MMAC)
signal processing applications that has been designed$100 to $300
to execute signal processing algorithms for which the2.9
principle algorithm that is multiply-and-accumulate5.8
operation is similar to all other algorithms. In the$300 to $1000
implementation of DSP (Digital Signal Processor) and4.2
FPGA (Field Programmable Gate Array), design13.4
engineers focus on various parameters such as:$1000 to $10000
Power Consumption, System Performance, Form20
Factor, System’s Future Upgrade Ability,Medium (300 to 1000 MMAC)
Non-Recurring Engineering (NRE) Investment,$10 to $30
Bill-of-Materials (BOM) Cost and Project Risk. Generally1.4
the engineers know about DSP but not completely1.6
aware of FPGA and hence this creates a situation$30 to $100
where they need to select any one of them.2.8
 3
These devices are very different from each otherLow (
and designed to serve different purposes. DSP< $10
provide an optimized platform for signal processing1.8
algorithms implemented in software whereas FPGA 
were for glue logic. Nowadays, there are certain 
applications where both these devices deliverFor applications with perfor­mance requirements
optimum solutions. FPGA is the better choice forabove 1000 MMAC, FPGA/DSP Hybrid solu­tions are
networking applications and DSP is at its best in videooften the ideal solution. These applications often
applications. This example indicates their performanceinclude multiple signal processing algo­rithms, some
has gone through a remarkable change over theof which have low performance requirements. In
years.such cases, relatively inexpen­sive DSPs can
 implement the algorithms with low-to-medium
In terms of cost-performance values, DSP and FPGAperformance requirements, leaving the
are compared in three MMAC (Millions ofhigher-performance algorithms to FPGAs. For designs
Multiply-Accumulate Operations per Second)with MMAC re­quirement below 300 MMAC, DSPs
performance categories viz. High, Medium and Low.are in general the optimum solution from cost
MMAC is the number of fixed-point-32-bit orperformance perspective. For designs with MMAC
single-precision floating-point multiply-and-accumulaterequirement between 300 and 1000 MMAC, the DSP
operations that can be executed in units of millionsis generally preferable when it comes with application
per second. The table given below can help thespecific resources (such as video/audio ports, ARM
design engineers in making the right selectionprocessor, etc., as is the case with the DaVinci
between DSP and FPGA.digi­tal media processors). When a DSP with
 application specific resources does not exist, other
 aspects of the design must be considered.
MMAC Category