匯編器在微處理器的驗證和應用中舉足輕重，如何設計通用的匯編器一直是研究的熱點之一。本文提出了一種開放式的匯編器系統設計思想，在匯編語言與機器語言間插入中間代碼CMDL（code mapping description language）語言，打破匯編語言與機器語言的直接映射關系，由此建立起一套描述匯編語言與機器語言的開放式映射體系。基于此開放式映射體系開發了一套匯編器系統，具有較高層次上的通用性和可移植性。【關鍵詞】指令集，CMDL，匯編器，開放式 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.【關鍵詞】instruction set, symbol table, assembler, lexical analysis, retargetability
上傳時間： 2013-10-10
上傳用戶：meiguiweishi
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.
標簽： 4channel transla level 9519
上傳時間： 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.
上傳時間： 2013-10-09
上傳用戶：3294322651
The PCA9544A provides 4 interrupt inputs, one for each channeland one open drain interrupt output. When an interrupt is generated byany device, it will be detected by the PCA9544A and the interruptoutput will be driven LOW. The channel need not be active fordetection of the interrupt. A bit is also set in the control byte.Bits 4 – 7 of the control byte correspond to channels 0 – 3 of thePCA9544A, respectively. Therefore, if an interrupt is generated byany device connected to channel 2, the state of the interrupt inputs isloaded into the control register when a read is accomplished.Likewise, an interrupt on any device connected to channel 0 wouldcause bit 4 of the control register to be set on the read. The mastercan then address the PCA9544A and read the contents of thecontrol byte to determine which channel contains the devicegenerating the interrupt. The master can then reconfigure thePCA9544A to select this channel, and locate the device generatingthe interrupt and clear it. The interrupt clears when the deviceoriginating the interrupt clears.
標簽： 4channel multiple 9544A 9544
上傳時間： 2014-12-28
上傳用戶：潛水的三貢
The PCA9670 provides general purpose remote I/O expansion for most microcontrollerfamilies via the two-line bidirectional bus (I2C-bus) and is a part of the Fast-mode Plusfamily.The PCA9670 is a drop-in upgrade for the PCF8574 providing higher Fast-mode Plus(Fm+) I2C-bus speeds (1 MHz versus 400 kHz) so that the output can support PWMdimming of LEDs, higher I2C-bus drive (30 mA versus 3 mA) so that many more devicescan be on the bus without the need for bus buffers, higher total package sink capacity(200 mA versus 100 mA) that supports having all 25 mA LEDs on at the same time andmore device addresses (64 versus 8) are available to allow many more devices on the buswithout address conflicts.
上傳時間： 2013-10-15
上傳用戶：stella2015
The PCA9671 provides general purpose remote I/O expansion for most microcontrollerfamilies via the two-line bidirectional bus (I2C-bus) and is a part of the Fast-mode Plus(Fm+) family.The PCA9671 is a drop in upgrade for the PCF8575 providing higher I2C-bus speeds(1 MHz versus 400 kHz) so that the output can support PWM dimming of LEDs, higherI2C-bus drive (30 mA versus 3 mA) so that many more devices can be on the bus withoutthe need for bus buffers, higher total package sink capacity (400 mA versus 100 mA) thatsupports having all 25 mA LEDs on at the same time and more device addresses (64versus 8) to allow many more devices on the bus without address conflicts.
上傳時間： 2013-10-12
上傳用戶：laomv123
The PCA9672 provides general purpose remote I/O expansion for most microcontrollerfamilies via the two-line bidirectional bus (I2C-bus) and is a part of the Fast-mode Plusfamily.The PCA9672 is a drop-in upgrade for the PCF8574 providing higher Fast-mode Plus(Fm+) I2C-bus speeds (1 MHz versus 400 kHz) so that the output can support PWMdimming of LEDs, higher I2C-bus drive (30 mA versus 3 mA) so that many more devicescan be on the bus without the need for bus buffers, higher total package sink capacity(200 mA versus 100 mA) that supports having all LEDs on at the same time and moredevice addresses (16 versus 8) are available to allow many more devices on the buswithout address conflicts.
上傳時間： 2013-10-23
上傳用戶：jasonheung
The PCA9673 provides general purpose remote I/O expansion for most microcontrollerfamilies via the two-line bidirectional bus (I2C-bus) and is a part of the Fast-mode Plusfamily.The PCA9673 is a drop in upgrade for the PCF8575 providing higher Fast-mode Plus(Fm+) I2C-bus speeds (1 MHz versus 400 kHz) so that the output can support PWMdimming of LEDs, higher I2C-bus drive (30 mA versus 3 mA) so that many more devicescan be on the bus without the need for bus buffers, higher total package sink capacity(400 mA versus 100 mA) that supports having all 25 mA LEDs on at the same time andmore device addresses (16 versus 8) are available to allow many more devices on the buswithout address conflicts.
上傳時間： 2013-10-29
上傳用戶：wkchong
The PCA9674/74A is a drop-in upgrade for the PCF8574/74A providing higher Fast-modePlus I2C-bus speeds (1 MHz versus 400 kHz) so that the output can support PWMdimming of LEDs, higher I2C-bus drive (30 mA versus 3 mA) so that many more devicescan be on the bus without the need for bus buffers, higher total package sink capacity(200 mA versus 100 mA) that supports having all LEDs on at the same time and moredevice addresses (64 versus 8) are available to allow many more devices on the buswithout address conflicts.
上傳時間： 2013-10-22
上傳用戶：wwwwwen5
The Philips family of Multiplexers and Switches consists of bi-directional translating switches controlled via the I2C or SMBus to fan out an upstream SCL/SDA pair to 2, 4 or 8 downstream channels of SCx/SDx pairs. The Multiplexers allow only one downstream channel to be selected at a time, while the Switches allow any individual downstream channel or combination of downstream channels to be selected, depending on the content of the programmable control register. Once one or several channels have been selected, the device acts as a wire, allowing the master on the upstream channel to send commands to devices on all the active downstream channels, and devices on the active downstream channels to communicate with each other and the master. External pull-up resistors are used to pull each individual channel up to the desired voltage level. Combined interrupt output and hardware reset input are device options that are featured.
上傳時間： 2013-10-11
上傳用戶：dianxin61
