The STWD100 watchdog timer circuits are self-contained devices which prevent systemfailures that are caused by certain types of hardware errors (non-responding peripherals,bus contention, etc.) or software errors (bad code jump, code stuck in loop, etc.).The STWD100 watchdog timer has an input, WDI, and an output, WDO (see Figure 2). Theinput is used to clear the internal watchdog timer periodically within the specified timeoutperiod, twd (see Section 3: Watchdog timing). While the system is operating correctly, itperiodically toggles the watchdog input, WDI. If the system fails, the watchdog timer is notreset, a system alert is generated and the watchdog output, WDO, is asserted (seeSection 3: Watchdog timing).The STWD100 circuit also has an enable pin, EN (see Figure 2), which can enable ordisable the watchdog functionality. The EN pin is connected to the internal pull-downresistor. The device is enabled if the EN pin is left floating.
針對使用硬件描述語言進行設計存在的問題，提出一種基于FPGA并采用DSP Builder作為設計工具的數字信號處理器設計方法。并按照Matlab/Simulink/DSP Builder/QuartusⅡ設計流程，設計了一個12階FIR 低通數字濾波器，通過Quartus 時序仿真及嵌入式邏輯分析儀SignalTapⅡ硬件測試對設計進行了驗證。結果表明，所設計的FIR 濾波器功能正確，性能良好。
Abstract:
Aiming at the problems in designing DSP using HDL，a method of designing DSP based on FPGA which using DSP Builder as designed tool is pointed out.A 12-order low-pass FIR digital filter was designed according to the process of Matlab/Simulink/DSP Builder/QuartusⅡ, and the design was verified by the timing simulation based on QuartusⅡand practical test based on SignalTapⅡ. The result shows the designed filter is correct in function and good in performance.
中文版詳情瀏覽：http://www.elecfans.com/emb/fpga/20130715324029.html
Xilinx UltraScale:The Next-Generation Architecture for Your Next-Generation Architecture
The Xilinx® UltraScale™ architecture delivers unprecedented levels of integration and capability with ASIC-class system- level performance for the most demanding applications.
The UltraScale architecture is the industr y's f irst application of leading-edge ASIC architectural enhancements in an All Programmable architecture that scales from 20 nm planar through 16 nm FinFET technologies and beyond, in addition to scaling from monolithic through 3D ICs. Through analytical co-optimization with the X ilinx V ivado® Design Suite, the UltraScale architecture provides massive routing capacity while intelligently resolving typical bottlenecks in ways never before possible. This design synergy achieves greater than 90% utilization with no performance degradation.
Some of the UltraScale architecture breakthroughs include:
• Strategic placement (virtually anywhere on the die) of ASIC-like system clocks, reducing clock skew by up to 50%
• Latency-producing pipelining is virtually unnecessary in systems with massively parallel bus architecture, increasing system speed and capability
• Potential timing-closure problems and interconnect bottlenecks are eliminated, even in systems requiring 90% or more resource utilization
• 3D IC integration makes it possible to build larger devices one process generation ahead of the current industr y standard
• Greatly increased system performance, including multi-gigabit serial transceivers, I/O, and memor y bandwidth is available within even smaller system power budgets
• Greatly enhanced DSP and packet handling
The Xilinx UltraScale architecture opens up whole new dimensions for designers of ultra-high-capacity solutions.
Express Mode uses an 8-bit wide bus path for fast configuration of Xilinx FPGAs. Thisapplication note provides information on how to perform Express configuration specifically forthe Spartan™-XL family. The Express mode signals and their associated timing are defined.The steps of Express configuration are described in detail, followed by detailed instructions thatshow how to implement the configuration circui
This application note covers the design considerations of a system using the performance
features of the LogiCORE™ IP Advanced eXtensible Interface (AXI) Interconnect core. The
design focuses on high system throughput through the AXI Interconnect core with F
MAX
and
area optimizations in certain portions of the design.
The design uses five AXI video direct memory access (VDMA) engines to simultaneously move
10 streams (five transmit video streams and five receive video streams), each in 1920 x 1080p
format, 60 Hz refresh rate, and up to 32 data bits per pixel. Each VDMA is driven from a video
test pattern generator (TPG) with a video timing controller (VTC) block to set up the necessary
video timing signals. Data read by each AXI VDMA is sent to a common on-screen display
(OSD) core capable of multiplexing or overlaying multiple video streams to a single output video
stream. The output of the OSD core drives the DVI video display interface on the board.
Performance monitor blocks are added to capture performance data. All 10 video streams
moved by the AXI VDMA blocks are buffered through a shared DDR3 SDRAM memory and are
controlled by a MicroBlaze™ processor.
The reference system is targeted for the Virtex-6 XC6VLX240TFF1156-1 FPGA on the
Xilinx® ML605 Rev D evaluation board
The C8051F020/1/2/3 devices are fully integrated mixed-signal System-on-a-Chip MCUs with 64 digital I/O pins (C8051F020/2) or 32 digital I/O pins (C8051F021/3). Highlighted features are listed below; refer to Table 1.1 for specific product feature selection.
Abstract: This application note describes system-level characterization and modeling techniques for radio frequency (RF) and microwavesubsystem components. It illustrates their use in a mixed-signal, mixed-mode system-level simulation. The simulation uses an RF transmitterwith digital predistortion (DPD) as an example system. Details of this complex system and performance data are presented.
針對UHF讀寫器設計中，在符合EPC Gen2標準的情況下，對標簽返回的高速數據進行正確解碼以達到正確讀取標簽的要求，提出了一種新的在ARM平臺下采用邊沿捕獲統計定時器數判斷數據的方法，并對FM0編碼進行解碼。與傳統的使用定時器定時采樣高低電平的FM0解碼方法相比，該解碼方法可以減少定時器定時誤差累積的影響；可以將捕獲定時器數中斷與數據判斷解碼相對分隔開，使得中斷對解碼影響很小，實現捕獲與解碼的同步。通過實驗表明，這種方法提高了解碼的效率，在160 Kb/s的接收速度下，讀取一張標簽的時間約為30次/s。
Abstract:
Aiming at the requirement of receiving correctly decoded data from the tag under high-speed communication which complied with EPC Gen2 standard in the design of UHF interrogator， the article introduced a new technology for FM0 decoding which counted the timer counter to judge data by using the edge interval of signal capture based on the ARM7 platform. Compared with the traditional FM0 decoding method which used the timer timed to sample the high and low level， the method could reduce the accumulation of timing error and could relatively separate capture timer interrupt and the data judgment for decoding， so that the disruption effect on the decoding was small and realizd synchronization of capture and decoding. Testing result shows that the method improves the efficiency of decoding， at 160 Kb/s receiving speed， the time of the interrogator to read a tag is about 30 times/s.
Single-Ended and Differential S-Parameters
Differential circuits have been important incommunication systems for many years. In the past,differential communication circuits operated at lowfrequencies, where they could be designed andanalyzed using lumped-element models andtechniques. With the frequency of operationincreasing beyond 1GHz, and above 1Gbps fordigital communications, this lumped-elementapproach is no longer valid, because the physicalsize of the circuit approaches the size of awavelength.Distributed models and analysis techniques are nowused instead of lumped-element techniques.Scattering parameters, or S-parameters, have beendeveloped for this purpose [1]. These S-parametersare defined for single-ended networks. S-parameterscan be used to describe differential networks, but astrict definition was not developed until Bockelmanand others addressed this issue [2]. Bockelman’swork also included a study on how to adapt single-ended S-parameters for use with differential circuits[2]. This adaptation, called “mixed-mode S-parameters,” addresses differential and common-mode operation, as well as the conversion betweenthe two modes of operation.This application note will explain the use of single-ended and mixed-mode S-parameters, and the basicconcepts of microwave measurement calibration.
