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

 

 

 

 

 

 

 

 

 

 

 

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C callable

 

 

 

 

 

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Reentrant

 

 

 

 

 

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etc.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Algorithm Component Model

 

 

 

 

 

 

 

 

 

 

 

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Modules

 

 

 

 

 

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Packaging

 

 

 

 

 

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Generic interfaces

 

 

 

 

 

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etc.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rules for TMS320C2x

 

 

 

Rules for TMS320C5x

 

Rules for TMS320C6x

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Interrupt usage

 

 

 

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Interrupt usage

 

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Interrupt usage

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Memory usage

 

 

 

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Memory usage

 

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Memory usage

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Register usage

 

 

 

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Register usage

 

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Register usage

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etc.

 

 

 

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etc.

 

 

 

 

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etc.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Telecom

Imaging

 

 

Audio

Automotive

 

 

Other

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vocoders

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JPEG

 

 

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coders

S etc.

 

 

 

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echo cancel

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etc.

 

 

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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.

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Overview

SPRU352G –June 2005 –Revised February 2007

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Contents Users Guide Rules and GuidelinesSubmit Documentation Feedback Contents Use of the DMA Resource Urls List of Figures Intended Audience Read This First Document Overview Rule n Related DocumentationText Conventions Guideline nOverview Scope of the Standard Rules for TMS320C5x Rules for TMS320C6xRules and Guidelines Requirements of the StandardGoals of the Standard Intentional OmissionsSystem Architecture FrameworksAlgorithms Core Run-Time SupportGeneral Programming Guidelines Threads Use of C LanguageThreads and Reentrancy RulePreemptive vs. Non-Preemptive Multitasking ReentrancyExample Data Memory Data MemoryMemory Spaces Scratch versus PersistentScratch vs Persistent Memory Allocation Algorithm versus Application GuidelineROM-ability Program MemorySection Name Purpose Use of Peripherals Use of PeripheralsAlgorithm Component Model Interfaces and Modules Algorithms PackagingInterfaces and Modules Implementation Fir.hExternal Identifiers Module Initialization and Finalization Naming ConventionsModule Instance Objects Design-Time Object Creation Run-Time Object Creation and DeletionModule Configuration Example ModuleMultiple Interface Support Element Interface InheritanceSummary Description RequiredAlgorithms AlgorithmsPackaging Object CodeHeader Files Debug Verses ReleaseModuleversvendorvariant.1arch Algorithm Performance Characterization Data Memory Program Memory Interrupt Latency Execution TimeExternal Heap MemorySize Stack Memory Static Local and Global Data MemoryData Bss Object files Size Mips Is Not Enough Interrupt LatencyExecution Time OperationExecution Time Model Execution Timeline for Two Periodic Tasks198000 Process59000 198000 Submit Documentation Feedback DSP-Specific Guidelines CPU Register Types Register TypesEndian Byte Ordering Use of Floating PointTMS320C6xxx Rules and Guidelines Data ModelsRegister Use Type Register ConventionsStatus Register CSR Field Use TypeTMS320C54xx Rules and Guidelines Interrupt LatencyProgram Models TMS320C54xx Rules and Guidelines ST0 Field Name Use Type Status RegistersST1 Field Name Use Type Stack Architecture TMS320C55x Rules and GuidelinesPmst Field Name Use Type Relocatability ExampleSSP ST2 Field Name Use Type Status BitsST3 Field Name Use Type Homy TMS320C24xx Guidelines GeneralTMS320C28x Rules and Guidelines TMS320C28x Rules and GuidelinesXAR0 M0M1MAP Use of the DMA Resource Submitting DMA Transfer RequestsOverview Algorithm and FrameworkRequirements for the Use of the DMA Resource Logical ChannelData Transfer Properties Data Transfer SynchronizationDMA Guideline Abstract InterfaceDMA Rule Data Transfers bytes Frequency Resource CharacterizationAverage Maximum Runtime APIs Strong Ordering of DMA Transfer RequestsSubmitting DMA Transfer Requests Device Independent DMA Optimization GuidelineCache Coherency Issues for Algorithm Producers 13 C6xxx Specific DMA Rules and GuidelinesSupporting Packed/Burst Mode DMA Transfers 14 C55x Specific DMA Rules and GuidelinesInter-Algorithm Synchronization Minimizing Logical Channel Reconfiguration OverheadAddressing Automatic Endianism Conversion Issues Non-Preemptive SystemPreemptive System Algorithm B Algorithm a Inter-Algorithm Synchronization Appendix a General Rules Performance Characterization Rules DMA RulesGeneral Guidelines DMA Guidelines Submit Documentation Feedback DSP/BIOS Run-time Support Library Core Run-Time APIsDSP/BIOS Run-time Support Library TI C-Language Run-Time Support LibraryBibliography BooksSubmit Documentation Feedback Glossary Glossary of TermsGlossary of Terms Glossary of Terms Important Notice
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