DSP systems and, in particular, real-time DSP systems application of d - PDF document

DSP systems and, in particular, real-time DSP systems application of data-driven behavioursdefined by mathematical algorithmsstrict timing constraintsDSP processors are designed for repetitive, numerically DSP applications define two main requirementssequence of operations must be performed in given timeaccuracy of results must be less than specifiedDSP processors contain features to improve the accuracy and performance of computations DSP Processors:DSP Processors:The Most Important FeaturesThe Most Important FeaturesFast multiply-accumulatesingle-instruction cycle MACmultiplier and accumulator integrated into main arithmetic unit (data path)Multiple-access memory parallel instruction fetch and Specialized addressing dedicated address Specialized execution efficient looping capabilitiesSpecialized features to accuracyinput/output interfaces processor is divided into procesoris complex or requires large number of I/O separate packages allow use of smaller and cheaper increased flexibilityButterfly DSP: LH9124 processor and LH9320 address generator are separate components. Several address generators can be used with a single processor.Multiprocessorshigh-performance systems requiring programmabilitysome DSP’shave been designed especially for multiprocessor systemsTMS320C4X and ADSP-2106X have dedicated communication ports for inter-processor TMS320C8X contains four DSP processors and a RISC processor 6 Custom HWDSP CoresDSP CoresFinal chip is combination ofexisting development toolsexisting SW librarieslow production costlow power consumptionUsed in high-volume designs DSP Core Based DSP Core Based ASICsASICs DSP CoreSpeech Coding ASICAudio ASICModem ASICDigital Cellular TelephoneHi-FiAudio EquipmentFax MachineWireless LANApplication-specific Foundry-Captive Corescore vendor provides also the foundry services for TI: standard DSP processors are macrocellswhich are surrounded by full-custom layouts, standard celss, or gate arrays or mixture of these.SGS-Thompson: D950-CORE is offered as macrocellin standard ASIC library.core vendor licenses the core design to the customer, who selects an appropriate typically optimized full-custom layout compatible with fabrication process of a particular foundryalso synthesizable HDL foundry selected freely Modification of the core itself rather than including additional surrounding circuitryDSP processor, which may be extended or modifiedadditional functional units in data path bit manipulation unitModifications in core must be reflected also to the AT&T Microelectronics: DSP1600 was designed for easy attachment of extra execution units into the data path and the development tools support new units.Philips: EPICS core has been demonstrated with different word widths. General-Purpose Microprocessors in for less-demanding DSP compared to DSP processorsmore cost effectivedevelopment tools more sophisticated and powerfulRISCshave features to single instruction cycle MAC (under certain circumstances)software-only DSP with loose requirementsscientific and engineering DSP simulations (no real-time requirements)cost effective (no extra hardware required)extended with add-on on-board DSP processorsA/D and D/A converterstelephone line interfaces Custom Hardwarethe best performancethe lowest production costboard level realization the most standard logic devicesfixed-function or configurable arithmetic unitsapplication-specific processorsdevelopment may be time-difficult to modify (fixed nature)Implementation options exclusiveIn reality, DSP systems different technologies for different parts of the system