基于单DSP的VoIP模拟电话适配器研究与实现:提出和实现了一种新颖的基于单个通用数字信号处理器(DSP)的VoIP模拟电话适配器方案。DSP的I/O和存储资源非常有限，通常适于运算密集型应用，不适宜控制密集型应用[5]。该系统高效利用单DSP的I/O和片内外存储器资源，采用μC/OS-II嵌入式实时操作系统，支持SIP和TCP-UDP/IP协议，通过LAN或者宽带接入，使普通电话机成为Internet终端，实现IP电话。该系统软硬件结构紧凑高效，运行稳定，成本低，具有广阔的应用前景。关键词：模拟电话适配器；IP电话；数字信号处理器；μC/OS-II 【Abstract】This paper presents a VoIP ATA solution based on a single digital signal processor (DSP). DSPs are suitable for arithmetic-intensiveapplication and unsuitable for control-intensive application because of the limitation of I/O and memory resources. This solution is based on a 16-bitfixed-point DSP and μC/OS-II embedded real-time operating system. It makes good use of the limited resources, supports SIP and TCP-UDP/IPprotocol. It can connect the analog telephone to Internet and realize the VoIP application. This system has a great future for its high efficiency andlow cost.【Key words】Analog telephone adapter (ATA); Voice over Internet protocol (VoIP); Digital signal processor (DSP); μC/OS-II Research and Implementation of VoIPATA Based on Single DSP
上传时间： 2013-11-20
上传用户：Wwill
Designing Boards with Atmel AT89C51, AT89C52, AT89C1051, and AT89C2051 for Writing Flash at In-Circuit Test:Recent improvements in chips andtesters have made it possible for thetester to begin taking over the role traditionallyassigned to the PROM programmer.Instead of having a PROM programmerwrite nonvolatile memoriesbefore assembling the board, the in-circuittester writes them during in-circuittesting operations. Many Teradyne Z18-series testers are now in use loadingcode into nonvolatile memories, microcontrollersand in-circuit programmable logic devices. The purpose of this note is to explain how the Z18 approaches the writing task for Atmel AT89C series IC’s,so that designers of boards using these chips can get the best results.
标签： Designing Boards Atmel with
上传时间： 2013-11-20
上传用户：lijianyu172
The μPSD32xx family, from ST, consists of Flash programmable system devices with a 8032 MicrocontrollerCore. Of these, the μPSD3234A and μPSD3254A are notable for having a complete implementationof the USB hardware directly on the chip, complying with the Universal Serial Bus Specification, Revision1.1.This application note describes a demonstration program that has been written for the DK3200 hardwaredemonstration kit (incorporating a μPSD3234A device). It gives the user an idea of how simple it is to workwith the device, using the HID class as a ready-made device driver for the USB connection.IN-APPLICATION-PROGRAMMING (IAP) AND IN-SYSTEM-PROGRAMMING (ISP)Since the μPSD contains two independent Flash memory arrays, the Micro Controller Unit (MCU) can executecode from one memory while erasing and programming the other. Product firmware updates in thefield can be reliably performed over any communication channel (such as CAN, Ethernet, UART, J1850)using this unique architecture. For In-Application-Programming (IAP), all code is updated through theMCU. The main advantage for the user is that the firmware can be updated remotely. The target applicationruns and takes care on its own program code and data memory.IAP is not the only method to program the firmware in μPSD devices. They can also be programmed usingIn-System-Programming (ISP). A IEEE1149.1-compliant JTAG interface is included on the μPSD. Withthis, the entire device can be rapidly programmed while soldered to the circuit board (Main Flash memory,Secondary Boot Flash memory, the PLD, and all configuration areas). This requires no MCU participation.The MCU is completely bypassed. So, the μPSD can be programmed or reprogrammed any time, anywhere, even when completely uncommitted.Both methods take place with the device in its normal hardware environment, soldered to a printed circuitboard. The IAP method cannot be used without previous use of ISP, because IAP utilizes a small amountof resident code to receive the service commands, and to perform the desired operations.
标签： Demonstration 3200 USB for
上传时间： 2014-02-27
上传用户：zhangzhenyu
This white paper discusses how market trends, the need for increased productivity, and new legislation have accelerated the use of safety systems in industrial machinery. This TÜV-qualified FPGA design methodology is changing the paradigms of safety designs and will greatly reduce development effort, system complexity, and time to market. This allows FPGA users to design their own customized safety controllers and provides a significant competitive advantage over traditional microcontroller or ASIC-based designs. Introduction The basic motivation of deploying functional safety systems is to ensure safe operation as well as safe behavior in cases of failure. Examples of functional safety systems include train brakes, proximity sensors for hazardous areas around machines such as fast-moving robots, and distributed control systems in process automation equipment such as those used in petrochemical plants. The International Electrotechnical Commission’s standard, IEC 61508: “Functional safety of electrical/electronic/programmable electronic safety-related systems,” is understood as the standard for designing safety systems for electrical, electronic, and programmable electronic (E/E/PE) equipment. This standard was developed in the mid-1980s and has been revised several times to cover the technical advances in various industries. In addition, derivative standards have been developed for specific markets and applications that prescribe the particular requirements on functional safety systems in these industry applications. Example applications include process automation (IEC 61511), machine automation (IEC 62061), transportation (railway EN 50128), medical (IEC 62304), automotive (ISO 26262), power generation, distribution, and transportation. 图Figure 1. Local Safety System
上传时间： 2013-11-05
上传用户：维子哥哥
Designing withProgrammable Logicin an Analog WorldProgrammable logic devicesrevolutionized digital design over 25years ago, promising designers a blankchip to design literally any functionand program it in the field. PLDs canbe low-logic density devices that usenonvolatile sea-of-gates cells calledcomplex programmable logic devices(CPLDs) or they can be high-densitydevices based on SRAM look-up tables
标签： Solutions Analog Xilinx FPGAs
上传时间： 2013-11-01
上传用户：a67818601
Designing withProgrammable Logicin an Analog WorldProgrammable logic devices revolutionizeddigital design over 25 years ago,promising designers a blank chip todesign literally any function and programit in the field. PLDs can be low-logicdensity devices that use nonvolatilesea-of-gates cells called complexprogrammable logic devices (CPLDs)or they can be high-density devicesbased on SRAM look-up tables (LUTs)
标签： Solutions Analog Altera FPGAs
上传时间： 2013-11-08
上传用户：虫虫虫虫虫虫
This application note shows how to achieve low-cost, efficient serial configuration for Spartan FPGA designs. The approachrecommended here takes advantage of unused resources in a design, thereby reducing the cost, part count, memory size,and board space associated with the serial configuration circuitry. As a result, neither processor nor PROM needs to be fullydedicated to performing Spartan configuration.In particular, information is provided on how the idle processing time of an on-board controller can be used to loadconfiguration data from an off-board source. As a result, it is possible to upgrade a Spartan design in the field by sending thebitstream over a network.
上传时间： 2014-08-16
上传用户：adada
The introduction of Spartan-3™ devices has createdmultiple changes in the evolution of embedded controldesigns and pushed processing capabilities to the “almostfreestage.” With these new FPGAs falling under $20, involume, with over 1 million system gates, and under $5for 100K gate-level units, any design with programmablelogic has a readily available 8- or 16-bit processor costingless than 75 cents and 32-bit processor for less than $1.50.
上传时间： 2013-12-10
上传用户：zgu489
The SDI standards are the predominant standards for uncompressed digital videointerfaces in the broadcast studio and video production center. The first SDI standard,SD-SDI, allowed standard-definition digital video to be transported over the coaxial cableinfrastructure initially installed in studios to carry analog video. Next, HD-SDI wasto support high-definition video. Finally, dual link HD-SDI and 3G-SDIdoubled the bandwidth of HD-SDI to support 1080p (50 Hz and 60 Hz) and other videoformats requiring more bandwidth than HD-SDI provides.
上传时间： 2013-10-08
上传用户：yjj631
Prakash Rashinkar has over 15 years experience in system design and verificationof embedded systems for communication satellites, launch vehicles and spacecraftground systems, high-performance computing, switching, multimedia, and wirelessapplications. Prakash graduated with an MSEE from Regional Engineering College,Warangal, in India. He lead the team that was responsible for delivering themethodologies for SOC verification at Cadence Design Systems. Prakash is anactive member of the VSIA Functional Verification DWG. He is currently Architectin the Vertical Markets and Design Environments Group at Cadence.
上传时间： 2014-01-24
上传用户：xinhaoshan2016
