Texas Instruments TMS320 DSP manual Scope of the Standard, Rules for TMS320C5x Rules for TMS320C6x

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Scope of the Standard

Digital Signal Processors (DSPs) are often programmed like "traditional" embedded microprocessors. That is, they are programmed in a mix of C and assembly language, they directly access hardware peripherals, and, for performance reasons, almost always have little or no standard operating system support. Thus, like traditional microprocessors, there is very little use of commercial off-the-shelf (COTS) software components for DSPs.

However, unlike general-purpose embedded microprocessors, DSPs are designed to run sophisticated signal processing algorithms and heuristics. For example, they may be used to detect DTMF digits in the presence of noise, to compress toll quality speech by a factor of 20, or for speech recognition in a noisy automobile traveling at 65 miles per hour.

Such algorithms are often the result of many years of doctoral research. However, because of the lack of consistent standards, it is not possible to use an algorithm in more than one system without significant reengineering. Since few companies can afford a team of DSP PhDs, and the reuse of DSP algorithms is so labor intensive, the time-to-market for a new DSP-based product is measured in years rather than in months.

This document defines a set of requirements for DSP algorithms that, if followed, allow system integrators to quickly assemble production-quality systems from one or more such algorithms. Thus, this standard is intended to enable a rich COTS marketplace for DSP algorithm technology and to significantly reduce the time-to-market for new DSP-based products.

1.1Scope of the Standard

The TMS320 DSP Algorithm Standard defines three levels of guidelines.

Figure 1-1. TMS320 DSP Algorithm Standard Elements

Level 1

Level 2

Level 3

Level 4

General Programming Guidelines
S	C callable					S	Reentrant
S No hard coded addresses						S	etc.
Algorithm Component Model
S	Modules					S	Packaging
S	Generic interfaces					S	etc.
Rules for TMS320C2x				Rules for TMS320C5x					Rules for TMS320C6x
S	Interrupt usage			S	Interrupt usage				S	Interrupt usage
S	Memory usage			S	Memory usage				S	Memory usage
S	Register usage			S	Register usage				S	Register usage
S	etc.			S	etc.				S	etc.
Telecom		Imaging				Audio		Automotive			Other
S	vocoders	S	JPEG			S	coders	S etc.
S	echo cancel	S	etc.			S	etc.

Setc.

Level 1 contains programming guidelines that apply to all algorithms on all DSP architectures regardless of application area. Almost all recently developed software modules follow these common sense guidelines already, so this level just formalizes them.

Level 2 contains rules and guidelines that enable all algorithms to operate harmoniously within a single system. Conventions are established for the algorithm'suse of data memory and names for external identifiers, for example. In addition, simple rules for how algorithms are packaged are also specified.

10 Overview SPRU352G –June 2005 –Revised February 2007

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