Texas Instruments TMS320C28x™ Digital Signal Processor Opens New Possibilities for Designing Digital Control Systems
Today's digital control systems are being asked to do more than ever for less system cost. Manufacturers of a wide range of industrial, consumer, computer, automotive and other applications are seeking ways to make their products more versatile and reliable, while at the same time less expensive and more energy-efficient. Sophisticated software algorithms, which make these advances possible, require digital control processors capable of executing more instructions in less time with greater precision than ever.
The new TMS320C28x™ digital signal processor (DSP) core from Texas Instruments (TI) provides the performance needed for these advanced algorithms, along with higher precision and an instruction set that reduces common control operations to fewer steps. In addition, C28x™ DSP technology offers code compatibility with TI's TMS320C24x™ DSPs, already widely used in digital control systems, as well as software support designed specifically to simplify the development of digital control applications. The TMS320C28x™ DSPs based on the C28x™ DSP core will be easier to use, reducing time-to-market for new product development, and their optimized performance will open up new application possibilities for digital control systems.
Significance of Digital Control
Real-time digital control is becoming pervasive in a wide variety of industrial, automotive, computer, communications, consumer and other equipment areas. Motors increasingly employ electronic control to achieve greater operating efficiency, reduce energy consumption, operate in variable speed without gears or pulleys, compensate for changes in load, perform multimotor synchronization and improve reliability. Uninterruptible power supplies (UPS) and switching power supplies protect network equipment and data from the damage that can result from voltage spikes, low voltages and other inconsistencies in line power. Mass storage products, such as hard disk drives (HDDs), achieve extremely high numbers of tracks per inch for ever-greater density of data storage. Automotive applications such as hybrid electric vehicles achieve ultra efficient and cost-effective electric motor control.
Digital control systems will benefit from the optimized performance that the C28x™ DSP core delivers. Capable of executing 400 million instructions per second (MIPS), the C28x™ DSP offers a performance enhancement within TI's widely used C2000™ DSP platform. These additional MIPS give system designers the performance margin needed to implement sophisticated signal processing techniques that will drive the capabilities of digital control to new levels.
For instance, C28x™ DSPs can save costs in motors by implementing control using fewer motion sensors and minimizing motor vibration and noise through the control of signal resonances. Optimized performance enables any type of system to sample signals, such as line power, more frequently reducing sample jitter and achieving improved precise control for a more stable system. In fact, in many applications, customers are able to use this additional DSP processing power to further analyze motor operation characteristics and further optimize the control, essentially using the motor as a sensor.
An Architecture Designed for Control
The C28x™ DSP represents a leap forward, not only in raw processing power, but also in the quality of performance for control systems. Greater precision, a larger address range, improved pipelining and other hardware features serve to optimize the C28x™ DSP for use in targeted applications.
A 32 X 32 single cycle multiply-accumulate (MAC) function, supplemented by 64-bit shift and saturate operations, vastly increases the speed and resolution of mathematical operations. Extended addressing supports up to 8 megabytes (MB) of program memory and up to 8 gigabytes (GB) of data, providing greater support for extensive control procedures. With its 32-bit wide bus structure and predominantly 16-bit instruction set, the processor fetches two instructions simultaneously, achieving near zero wait states, while allowing designers to use slower, less expensive memories.
The core architecture features a deeper pipeline for improved memory operations, supported by improved conditional branching that keeps the pipeline full and minimizes latencies. Automatic context save and restore features enable fast interrupt service routines (ISRs) with minimal overhead in cycles. Fast ISRs are essential to control systems, which must continually deal with input/output (I/O) operations. All of these architectural enhancements make the C28x™ DSP a more efficient machine for performing signal processing and control.
A Control-Specific Instruction Set
In addition to its DSP operation codes, the C28x™ DSP instruction set includes operations often found in microcontrollers. These instructions not only simplify the programming of control routines with the high-level C language, they make the code more compact in memory and faster in execution. The C28x™ DSP is software code compatible with the C24x™ DSP family allowing manufacturers to preserve their software engineering and directly transfer ongoing development from C24x™ DSPs to new C28x™ DSP devices.
One of the important control feature sets of the C28x™ DSP is its read-modify-write (RMW) instructions that performs a common series of program steps in a single operation. Using the atomic RMW instruction, a programmer can treat any memory location as a register. This flexibility offers significant advantages in working with control code, where a large number of values may be stored and retrieved for diverse system tasks. Moreover, DSP performance allows the RMW operation to be completed in 2.5 nanoseconds (ns), compared to 120 ns in microcontrollers.
Other control features include improved saturation, and circular addressing, which simplify the implementation of recursive control algorithms and filtering with the C language. Stored conditional operations improve performance and a stack management feature allows offset indexing for improved C compiler efficiency.
eamlining Digital Control Development
Support for the new DSP includes features that help streamline the development of digital control systems. A highly efficient C/C++ compiler produces compiled code that is best in class and approaches hand-coded assembly in density. The compact compiled code of the C28x™ DSP runs faster, reducing system memory costs. The compiler's efficiency and C++ support allow software developers to work in a familiar high-level language without concerns about compromising performance. Manufacturers can concentrate their coding efforts in areas where they can get the greatest return.
TI's debugging tools link internal structures in the DSP with easy-to-use external emulation hardware and software. As a result, developers gain increased real-time visibility into the internal operation of the DSP, allowing them to debug their systems more quickly. Developers may seek added tools and software support from TI's extensive Third Party Network, the largest in the industry, which can help speed up system development.
Enabling Next-Generation Digital Control Systems
For advanced control applications of the future, TI's new C28x™ DSP core provides the technology of choice. With 400 MIPS of performance and 32x32 single cycle MAC capabilities, the C28x™ DSP architecture provides the power and precision needed for sophisticated signal processing and uniprocessor control. As manufacturers of industrial, consumer, computer, automotive and other applications push for higher capabilities in their products, they have and will continue to turn to TI's programmable C2000™ DSP platform for digital control.
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TRADEMARKS
TMS320C28x™ is a trademark of Texas Instruments Incorporated.
C28x™ is a trademark of Texas Instruments Incorporated.
TMS320C24x™ is a trademark of Texas Instruments Incorporated.
C2000™ is a trademark of Texas Instruments Incorporated.
TMS320C27x™ is a trademark of Texas Instruments Incorporated.
C24x™ is a trademark of Texas Instruments Incorporated.
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