4447874821161vsC6711_12| Application Note

4447874821161vsC6711_12| Application Note

LOW-COST SIMD

Considerations For Selecting a DSP Processor Why Buy The ADSP-21161?
The Analog Devices ADSP-21161 SIMD SHARC vs. Texas Instruments TMS320C6711 and TMS320C6712
Author : K. Srinivas

Introduction
Rich, powerful instruction sets, floating point precision and high speed execution make floating point Digital Signal Processors (DSPs) a popular choice for designers of Signal processing systems. Designers of systems ranging from medical imaging to graphical transform engines (arcade games) choose among floating point DSPs using criteria such as feature integration, computational power and IO capabilities. This application note discusses the features of two popular floating point DSP processors The ADSP 21161 compared with TMS320C6711 and TMS320C6712. Both the TMS320C6711 and TMS3206712 share the same TMS320C67xx floating point DSP core and a very similar set of onchip peripheral support. Hence both the processors are considered in this application note. Table 1 shows the comparison for two of the DSPs. The ADSP21161 offers the following features over the TMS320C6711/TMS32C6712 processors: Compute blocks Two compute blocks PEx and PEy are available which work on different data values but both execute th
e same instruction thus improving on the code density. This is called SIMD mode of execution. The compute blocks consist of an adder, multiplier, barrel shifter and a dedicated register file to load and store the data values. Each compute block provides parallel (multi function) instructions. The combination of SIMD and multi function instructions generates as much as 600 Megaflops of peak compute power from ADSP21161. Data Addressing ADSP21161 has two Data Address Generators (DAGs) to generate addresses for fetching data and/or programs on DM and PM buses. These DAGs execute instructions in parallel to the compute instructions. The DAGs support a variety of addressing modes and circular buffering. Memory Enormous RAM is available on chip in ADSP21161 processor. There is 128 K bytes of RAM available in this processor. This is equal to 21.3K of ADSP-21161 instructions. The onchip memory is dual ported. I/O capabilities Very flexible and on-intrusive DMA support that enables parallel transfers between an
y of 4 serial ports, 2 link ports and the external port. There are a total of 14 DMA channels are supported in ADSP21161. This allows for the connection of a number of peripherals to the DSP processor and ensures data availability.

24 Jun 2001

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