linux 中斷和設(shè)備驅(qū)動(dòng) 本章介紹L i n u x內(nèi)核是如何維護(hù)它支持的文件系統(tǒng)中的文件的，我們先介紹 V F S ( Vi r t u a lFile System，虛擬文件系統(tǒng))，再解釋一下L i n u x內(nèi)核的真實(shí)文件系統(tǒng)是如何得到支持的。L i n u x的一個(gè)最重要特點(diǎn)就是它支持許多不同的文件系統(tǒng)。這使 L i n u x非常靈活，能夠與許多其他的操作系統(tǒng)共存。在寫這本書的時(shí)候， L i n u x共支持1 5種文件系統(tǒng)： e x t、 e x t 2、x i a、 m i n i x、 u m s d o s、 msdos 、v f a t、 p r o c、 s m b、 n c p、 i s o 9 6 6 0、 s y s v、 h p f s、 a ffs 和u f s。無疑隨著時(shí)間的推移，L i n u x支持的文件系統(tǒng)數(shù)還會(huì)增加。
標(biāo)簽： linux 中斷 設(shè)備驅(qū)動(dòng)
上傳時(shí)間： 2013-11-13
上傳用戶：zxh122
The PCA9534 is a 16-pin CMOS device that provide 8 bits of General Purpose parallel Input/Output (GPIO) expansion for I2C-bus/SMBus applications and was developed to enhance the NXP Semiconductors family of I2C-bus I/O expanders. The improvements include higher drive capability, 5 V I/O tolerance, lower supply current, individual I/O configuration, 400 kHz clock frequency, and smaller packaging. I/O expanders provide a simple solution when additional I/O is needed for ACPI power switches, sensors, push buttons, LEDs, fans, etc.
標(biāo)簽： interru SMBus power 9534
上傳時(shí)間： 2013-10-10
上傳用戶：inwins
The PCA9535 and PCA9535C are 24-pin CMOS devices that provide 16 bits of GeneralPurpose parallel Input/Output (GPIO) expansion for I2C-bus/SMBus applications and wasdeveloped to enhance the NXP Semiconductors family of I2C-bus I/O expanders. Theimprovements include higher drive capability, 5 V I/O tolerance, lower supply current,individual I/O configuration, and smaller packaging. I/O expanders provide a simplesolution when additional I/O is needed for ACPI power switches, sensors, push buttons,LEDs, fans, etc.
上傳時(shí)間： 2013-10-21
上傳用戶：愛死愛死
The PCA9517 is a CMOS integrated circuit that provides level shifting between lowvoltage (down to 0.9 V) and higher voltage (2.7 V to 5.5 V) I2C-bus or SMBus applications.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 two buses of 400 pF. Usingthe PCA9517 enables the system designer to isolate two halves of a bus for both voltageand capacitance. The SDA and SCL pins are over voltage tolerant and arehigh-impedance when the PCA9517 is unpowered.
標(biāo)簽： translating Level 9517 PCA
上傳時(shí)間： 2013-12-25
上傳用戶：wsf950131
The PCA9555 is a 24-pin CMOS device that provides 16 bits of General Purpose parallelInput/Output (GPIO) expansion for I2C-bus/SMBus applications and was developed toenhance the NXP Semiconductors family of I2C-bus I/O expanders. The improvementsinclude higher drive capability, 5 V I/O tolerance, lower supply current, individual I/Oconfiguration, and smaller packaging. I/O expanders provide a simple solution whenadditional I/O is needed for ACPI power switches, sensors, push buttons, LEDs, fans, etc.The PCA9555 consists of two 8-bit Configuration (Input or Output selection); Input, Outputand Polarity Inversion (active HIGH or active LOW operation) registers. The systemmaster can enable the I/Os as either inputs or outputs by writing to the I/O configurationbits. The data for each Input or Output is kept in the corresponding Input or Outputregister. The polarity of the read register can be inverted with the Polarity Inversionregister. All registers can be read by the system master. Although pin-to-pin and I2C-busaddress compatible with the PCF8575, software changes are required due to theenhancements, and are discussed in Application Note AN469.
上傳時(shí)間： 2013-11-13
上傳用戶：fredguo
RSM232隔離RS-232收發(fā)器具備電源隔離、電氣隔離、RS-232收發(fā)器，有提高系統(tǒng)穩(wěn)定性，簡化設(shè)計(jì)等諸多優(yōu)點(diǎn)。完全符合EIA/TIA-232E和ITU-T V.28規(guī)格，采用5V電源供電，具有2500VDC的隔離電壓，波特率可高達(dá)115200bps
上傳時(shí)間： 2014-02-22
上傳用戶：ouyangtongze
The TRS232E is a dual driver/receiver that includes a capacitive voltage generator to supply TIA/RS-232-Fvoltage levels from a single 5-V supply. Each receiver converts TIA/RS-232-F inputs to 5-V TTL/CMOS levels.This receiver has a typical threshold of 1.3 V, a typical hysteresis of 0.5 V, and can accept ±30-V inputs. Eachdriver converts TTL/CMOS input levels into TIA/RS-232-F levels. The driver, receiver, and voltage-generatorfunctions are available as cells in the Texas Instruments LinASIC™ library.
標(biāo)簽： RECEIVER DRIVER DUAL 232
上傳時(shí)間： 2013-10-07
上傳用戶：waitingfy
The ISO7220 and ISO7221 are dual-channel digital isolators. To facilitate PCB layout, the channels are orientedin the same direction in the ISO7220 and in opposite directions in the ISO7221. These devices have a logic inputand output buffer separated by TI’s silicon-dioxide (SiO2) isolation barrier, providing galvanic isolation of up to4000 V. Used in conjunction with isolated power supplies, these devices block high voltage, isolate grounds, andprevent noise currents on a data bus or other circuits from entering the local ground and interfering with ordamaging sensitive circuitry.
標(biāo)簽： ISOLATORS DIGITAL DUAL
上傳時(shí)間： 2013-10-24
上傳用戶：hbsunhui
高壓雙管反激變換器的設(shè)計(jì):介紹一種雙管反激的電路拓?fù)?，分析了其工作原理，給出了一些關(guān)鍵技術(shù)參數(shù)的計(jì)算公式，設(shè)計(jì)并研制成功的30W 380V AC5 0H z/510V DC/+15.1 V DC(1A )、+5.2VDC(2A)輔助開關(guān)電源具有功率密度高、變換效率高、可靠性高等優(yōu)良的綜合性能。該變換器在高電壓輸人情況下有重要的應(yīng)用價(jià)值?！娟P(guān) 鍵 詞 】變換器，輔助開關(guān)電源，雙管反激 [Abstract】 A n e wt opologyfo rd oubles witchfl ybackc onverteris in troduced.Th eo perationp rincipleis a nalyzeda nds ome for mulas for calculating key parameters for the topology are presented. The designed and produced auxiliary switching power supply,i. e. 30W 380V AC5 0H z/5 10V DC/+15.1 V DC《1A )、+5.2 V DC《2A )，hase xcellentc omprehensivep erformances sucha sh ighp owerd ensity, hi ghc onversione fficiencya ndh ighr eliability.Th isc onverterh asim portanta pplicationv aluef orh igh input voltag [Keywords ]converter,au xiliary switchingp owers upply,do ubles witchf lybac
上傳時(shí)間： 2013-11-01
上傳用戶：Ants
文章提出了一種精簡指令集8 位單片機(jī)中, 算術(shù)邏輯單元的工作原理。在此基礎(chǔ)上, 對比傳統(tǒng)PIC 方案、以及在ALU 內(nèi)部再次采用流水線作業(yè)的332 方案、44 方案, 并用Synopsys 綜合工具實(shí)現(xiàn)了它們。綜合及仿真結(jié)果表明, 根據(jù)該單片機(jī)系統(tǒng)要求, 44 方案速度最高, 比332 方案可提高43.9%, 而面積僅比最小的332 方案增加1.6%。在分析性能差異的根本原因之后, 闡明了該方案的優(yōu)越性。關(guān)鍵詞: 單片機(jī), 精簡指令集, 算術(shù)邏輯單元, 流水線 Abstract: Work principle for ALU in an 8_bit RISC Singlechip microcomputer is described. The traditional PIC scheme, 332 Pipeline scheme and 44 Pipeline scheme are compared on the base of the principle, which are implemented using Synopsys design tools. Results from synthesis and simulation shows that 44 scheme operates the fast, which is 43.9% faster and only 1.6% larger than 332 scheme. The essential reason why the performance is so different is analyzed.Then the advantage of 44 scheme is clarified.Key words: Singlechip, Microcomputer, RISC, ALU, Pipeline
上傳時(shí)間： 2013-10-18
上傳用戶：xiaoyaa
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