匯編器在微處理器的驗(yàn)證和應(yīng)用中舉足輕重，如何設(shè)計(jì)通用的匯編器一直是研究的熱點(diǎn)之一。本文提出了一種開(kāi)放式的匯編器系統(tǒng)設(shè)計(jì)思想，在匯編語(yǔ)言與機(jī)器語(yǔ)言間插入中間代碼CMDL（code mapping description language）語(yǔ)言，打破匯編語(yǔ)言與機(jī)器語(yǔ)言的直接映射關(guān)系，由此建立起一套描述匯編語(yǔ)言與機(jī)器語(yǔ)言的開(kāi)放式映射體系。基于此開(kāi)放式映射體系開(kāi)發(fā)了一套匯編器系統(tǒng)，具有較高層次上的通用性和可移植性。【關(guān)鍵詞】指令集，CMDL，匯編器，開(kāi)放式 Design of Retargetable Assembler System Liu Ling Feng Wen Nan Wang Ying Chun Jiang An Ping Ji Li Jiu IME of Peking University, 100871【摘要】An assembler plays a very important role in the field of microprocessor verifications and applications, thus how to build a retargetable assembler system has been a hotspot in this field for long time. This paper presents a new method about the retargetable assembler system design.It provides a kind of language CMDL, code mapping description language. During the process of assembling, assembler languages are firstly translated to CMDL, and then mapped to the machine codes. In an other word, CMDL is inserted between assembler languages and machine codes during the translation procedure. As a medium code, CMDL has a lot of features, such as high extraction, strong descript capabilities. It can describe almost all attributes of assembler languages. By breaking the direct mapping relationship between assembler languages and machine codes, the complexities of machine codes are hided to the users, therefore, the new retargetable assembler system has higher retargetable level by converting the mapping from assembler languages and machine codes to assembler languages and CMDL, and implementationof it becomes easier. Based on the new mapping system structure, a retargetable assemblersystem is developed. It proved the whole system has good retargetability and implantability.【關(guān)鍵詞】instruction set, symbol table, assembler, lexical analysis, retargetability
上傳時(shí)間： 2013-10-10
上傳用戶：meiguiweishi
<Almost since the introduction of microcontrollers as electronic components there always has been an oscillatorcircuit on the device to make it work. From application point of view only some external components wererequired to make it work. However, to make sure that it will always work required more effort. This report is basedon feedback from the market from customers applying 8-bit mircrocontrollers.>
標(biāo)簽： oscillators X-tal bit mic
上傳時(shí)間： 2013-11-12
上傳用戶：穿著衣服的大衛(wèi)
The PCA9519 is a 4-channel level translating I2C-bus/SMBus repeater that enables theprocessor low voltage 2-wire serial bus to interface with standard I2C-bus or SMBus I/O.While retaining all the operating modes and features of the I2C-bus system during thelevel shifts, it also permits extension of the I2C-bus by providing bidirectional buffering forboth the data (SDA) and the clock (SCL) lines, thus enabling the I2C-bus or SMBusmaximum capacitance of 400 pF on the higher voltage side. The SDA and SCL pins areover-voltage tolerant and are high-impedance when the PCA9519 is unpowered.
標(biāo)簽： 4channel transla level 9519
上傳時(shí)間： 2013-11-19
上傳用戶：jisiwole
The PCA9541 is a 2-to-1 I2C-bus master selector designed for high reliability dual masterI2C-bus applications where system operation is required, even when one master fails orthe controller card is removed for maintenance. The two masters (for example, primaryand back-up) are located on separate I2C-buses that connect to the same downstreamI2C-bus slave devices. I2C-bus commands are sent by either I2C-bus master and are usedto select one master at a time. Either master at any time can gain control of the slavedevices if the other master is disabled or removed from the system. The failed master isisolated from the system and will not affect communication between the on-line masterand the slave devices on the downstream I2C-bus.
標(biāo)簽： master C-bus 9541 PCA
上傳時(shí)間： 2013-10-09
上傳用戶：3294322651
The PCA9557 is a silicon CMOS circuit which provides parallel input/output expansion for SMBus and I2C-bus applications. The PCA9557 consists of an 8-bit input port register, 8-bit output port register, and an I2C-bus/SMBus interface. It has low current consumption and a high-impedance open-drain output pin, IO0. The system master can enable the PCA9557’s I/O as either input or output by writing to the configuration register. The system master can also invert the PCA9557 inputs by writing to the active HIGH polarity inversion register. Finally, the system master can reset the PCA9557 in the event of a time-out by asserting a LOW in the reset input. The power-on reset puts the registers in their default state and initializes the I2C-bus/SMBus state machine. The RESET pin causes the same reset/initialization to occur without de-powering the part.
標(biāo)簽： C-bus SMBus reset port
上傳時(shí)間： 2014-01-18
上傳用戶：bs2005
Luminary Micro provides an analog-to-digital converter (ADC) module on some members of theStellaris microcontroller family. The hardware resolution of the ADC is 10 bits; however, due to noiseand other accuracy-diminishing factors, the true accuracy is less than 10 bits. This application noteprovides a software-based oversampling technique, resulting in an improved Effective Number OfBits (ENOB) in the conversion result. This document describes methods of oversampling an inputsignal, and the impact on precision and overall system performance.
標(biāo)簽： Oversampling Techniques ADC fo
上傳時(shí)間： 2013-12-17
上傳用戶：zhyiroy
基于PIC單片機(jī)的脈沖電源:設(shè)計(jì)了一種金屬凝固過(guò)程用脈沖電源。該電源采用PIC16F877作為主控芯片，實(shí)現(xiàn)對(duì)窄脈沖電流幅值的檢測(cè)，以及時(shí)電流脈沖幅值根據(jù)模糊PID算法進(jìn)行閑環(huán)控制。使用結(jié)果表明：該電源的輸出脈沖波形良好，電流幅值穩(wěn)定，滿足合金材料凝固過(guò)程的工藝要求且運(yùn)行穩(wěn)定可靠。關(guān)鍵詞：脈沖電源；PIC16F877單片機(jī)；模糊PID；閑環(huán)控制 Abstract：A kind of pulse power supply was designed which uses in the metal solidification process ．．I11is power supply used PIC16F877 to take the master control chip reali on to the narrow pulse electric current peak-to-peak value examination，carried on the closed-loop control to the electric current pulse peak-to-peak value basis fuzzy PID algorithm．The use result indicated ，this power supply output se profile is good，and the electric current peak-to-p~k value is stable，It satisfies the alloy material solidification process the technological requirement and movement stable reliable，Key words：p se po wer supply；PIC16F877single-chip microcontroller；f r PID；closed-loop control
上傳時(shí)間： 2013-10-27
上傳用戶：xcy122677
基于單DSP的VoIP模擬電話適配器研究與實(shí)現(xiàn):提出和實(shí)現(xiàn)了一種新穎的基于單個(gè)通用數(shù)字信號(hào)處理器(DSP)的VoIP模擬電話適配器方案。DSP的I/O和存儲(chǔ)資源非常有限，通常適于運(yùn)算密集型應(yīng)用，不適宜控制密集型應(yīng)用[5]。該系統(tǒng)高效利用單DSP的I/O和片內(nèi)外存儲(chǔ)器資源，采用μC/OS-II嵌入式實(shí)時(shí)操作系統(tǒng)，支持SIP和TCP-UDP/IP協(xié)議，通過(guò)LAN或者寬帶接入，使普通電話機(jī)成為Internet終端，實(shí)現(xiàn)IP電話。該系統(tǒng)軟硬件結(jié)構(gòu)緊湊高效，運(yùn)行穩(wěn)定，成本低，具有廣闊的應(yīng)用前景。關(guān)鍵詞：模擬電話適配器；IP電話；數(shù)字信號(hào)處理器；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
上傳時(shí)間： 2013-11-20
上傳用戶：Wwill
基于單片機(jī)的步進(jìn)電機(jī)開(kāi)環(huán)控制系統(tǒng):通過(guò)ATMEL89C51單片機(jī)對(duì)步進(jìn)電機(jī)進(jìn)行控制,主要介紹了步進(jìn)電機(jī)控制器、驅(qū)動(dòng)電路和LED顯示電路的設(shè)計(jì),實(shí)現(xiàn)了步進(jìn)電機(jī)的開(kāi)環(huán)控制。在步進(jìn)電機(jī)控制器的設(shè)計(jì)中,重點(diǎn)闡述了脈沖產(chǎn)生電路以及對(duì)速度的控制。該系統(tǒng)具有成本低、控制方便的特點(diǎn)。關(guān)鍵詞: 單片機(jī); 步進(jìn)電機(jī); 開(kāi)環(huán)控制 Abstract: The design using ATMEL89C51 single chip to control the step2motor with its controller, driving circuit and LED disp lay circuit to realize step motor open2loop controlwere introduced. For the controller in this design,the circuit to p roduce pulse and the speed controlwere expatiated emphatically. This system possesses features of lower cost, easier control.Key words: single ch ip; step2motor; open2loop con trol
標(biāo)簽： 單片機(jī) 步進(jìn)電機(jī) 開(kāi)環(huán) 控制系統(tǒng)
上傳時(shí)間： 2013-10-13
上傳用戶：cicizoe
摘要：本水位監(jiān)測(cè)報(bào)警器使用5V低壓直流電源（也可以用3節(jié)5號(hào)電池代替）就可以對(duì)5~15厘米的水位進(jìn)行監(jiān)測(cè)，用LED顯示和數(shù)碼管顯示水位，并可以對(duì)不再此范圍內(nèi)的水位發(fā)出報(bào)警。主要采用CD4066、74LS86、74LS32、CD4511芯片，再加上數(shù)碼管、蜂鳴器、發(fā)光二極管、電阻這些器件組成一個(gè)簡(jiǎn)單而靈敏的監(jiān)測(cè)報(bào)警電路，操作簡(jiǎn)單，接通電源即可工作。因?yàn)榇蟛糠蛛娐凡捎脭?shù)字電路，所以本水位監(jiān)測(cè)報(bào)警器還具有耗能低、準(zhǔn)確性高的特點(diǎn)。關(guān)鍵字：譯碼電路 報(bào)警電路 監(jiān)測(cè)電路 Abstract: The water level alarm monitoring the use of 5 V low-voltage DC power (can also use three batteries replaced on the 5th) will be able to 5 to 15 centimeters of water level monitoring, with LED display and digital display of water level, and this can no longer Within the scope of a water level alarm. Mainly CD4066, 74LS86, 74LS32, CD4511 chips, coupled with digital control, buzzer, light-emitting diode, the resistance of these devices composed of a simple and sensitive monitoring alarm circuits. Because the majority of circuits using digital circuitry, so the water level monitored alarm system also has low energy consumption, high accuracy of the characteristics. Keyword: Decoding circuit alarm circuit monitoring circuit
標(biāo)簽： 水位 監(jiān)測(cè)報(bào)警 系統(tǒng)原理
上傳時(shí)間： 2013-11-05
上傳用戶：王慶才
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