Digital signal processor of choice?

Digital signal processor (DSP) processor for a wide field of application, but in fact not a processor capable of satisfying all or most application needs, design engineers need select processor based on performance, cost, integration, development of ease and power consumption and other factors to be considered. DSP devices according to the design requirements can be divided into two categories. The first type, application area for low-cost, large-scale embedded systems, such as mobile phones, disk drive (DSP for servo motor control) as well as portable digital audio player, etc. In these applications in the price and integration are the most important consideration. For portable battery-powered devices, power consumption is also a key factor. Although these applications often need to be developed to run on a DSP application software and peripheral customer support hardware, but the ease of development requirements remains a minor factor, because mass production could share development costs, thereby reducing the development costs per product. Another one is the need to use complex algorithms on a large amount of data processed by applications, such as sonar and seismic detection, also need to use DSP devices. Class device volume General smaller, algorithm demanding, the product is fairly large and very complex. So the design engineer in select processor will ensure as far as possible to choose the best performance, ease of development and support of multiprocessor DSP devices. Sometimes, the design engineers prefer choosing out-of-the-box Development Board to develop system rather than from scratch and design of hardware and software, and can be used out-of-the-box functionality for developing application software library file. In the actual design should be based on specific application to select appropriate DSP. Different DSP has different characteristics, suitable for different applications, select keep the following points when you can follow. DSP development simplicity for different applications, the requirements for simplicity. For research and prototype development, General requirements for system tools can facilitate development. But if the company in the development of next-generation mobile phone products, cost is the most important factor, as long as they can reduce the cost of the final product, generally they are willing to endure a lengthy development, the use of sophisticated development tools (of course if significantly delayed the time to market is another matter). Therefore select the DSP considerations when software development tools (including compilations, link, simulation, commissioning, compilation, code libraries, and real-time operating systems, etc.), hardware tools (Development Board and Simulator) and advanced tools (such as code generation based on block diagram environment). Use these tools in the design process, as shown in Figure 4. Select DSP devices often have the problem of how to implement a programming. General design engineer to select the Assembly language or high level language (such as C or Ada), or a combination of both. Now most of the DSP programs use assembly language, because the compiler-generated assembly code optimized for General needs without manually program optimization, reducing program code size and make the process more reasonable to further accelerate the program execution speed. This kind of work for consumer electronics products are very meaningful, because through code optimization can compensate for the lack of DSP performance. Using high-level language compiler design engineers will find that floating-point DSP compiler performs better than the fixed-point DSP effects, there are several reasons: first, the most advanced language itself does not support decimal arithmetic; Secondly, floating-point processors generally has more than targeted processor instructions, instructions, rules, more suitable for restricted compiler processes; and, third, because of the floating-point processor support for larger storage, provides sufficient space. Compiler-generated code is generally lower than manually generated code. Whether it is a high-level language or assembly language programming, must pay attention to debugging and hardware simulation tools in use, because a large part of your development time will be spent here. Almost all manufacturers provide instruction set Simulator, pending the completion of the hardware, use instruction set Simulator for software debugging. If you are using a high-level language for advanced language debugger features for evaluation is important, including the possible and analog machine and/or hardware emulator running properties. Most of the DSP vendors provide hardware simulation tool, now many processor with on-chip debug emulation function/, through the use of a standard serial interface IEEE1149.1JTAG. The serial interface allows the simulation based on scanning, i.e. programmer through the interface to load the breakpoint, and then scan processor internal register to view processor reaches a breakpoint after the contents of a register and modify. Many manufacturers offer ready-made DSP development system board. The development of the hardware is not available until the completion of the Development Board to run software real-time debugging, you can improve the end product manufacturability. For some systems even small batches can be used as a final product the Development Board. Support for multiple processors in some data calculation of great applications, often require the use of multiple DSP processors. In this case, multiple processor interconnection and interconnect performance (on their traffic, cost and time delay) as important considerations. If ADI's ADSP-2106X series provides simplified multiprocessor system design of dedicated hardware. Power management and power consumption DSP devices are increasingly applied in portable products, these application power consumption is an important consideration, and DSP manufacturers as far as the product's power management and reduce operating voltage to reduce system power consumption. In some DSP device power management features include: a. lower operating voltage: many producers provide low voltage DSP version (3.3V, 2.5V, or 1.8V), this processor is in the same clock down power consumption far less than 5V power supply of similar products. b.“ Sleep "or" idle "mode: the vast majority of processors with the broken processor features some clock, reduce power consumption. In some cases, non-masked interrupt signals can be processor from "sleep" mode, in other cases, the only set of several external interrupts to wake up the processor. Some processors can provide different power saving function and delay of more than one "sleep" mode. C. programmable clock divider: some DSP allowed under software control to change the processor clock to a specific task, use the minimumClock frequency to reduce power consumption. D. perimeter control: some DSP device allows the program to stop the system is not used to the work of the external circuit. No matter how power management features, the design engineers to obtain excellent power saving design is difficult, because the DSP power with the implementation of the directive. Most manufacturers provide power indicators as typical or maximum value, and TI company gives the index is an exception, the application instance in detail in the implementation of the different directives and the different configurations of power consumption. Cost factors in meet the design requirements of the condition to make full use of low-cost DSP, even if this DSP programming is very difficult and bad flexibility. In the processor series, the cheaper processors feature fewer on-chip memory is less than the price of high-performance processors. Package different DSP device prices vary. For example, PQFP, TQFP package than the PGA package is much cheaper. In considering the costs to bear in mind that two points. First, the processor prices continued to decline; the second point, the price is also dependent on the volume, such as 10,000 tablets price may be higher than the price cheap 1,000 tablets.