The “bottom-line” metrics of cash flow, demand, price, and return on investment
are driven by a second set of financial metrics represented by value to the
customer, cost, and the pace of innovation. Get them right relative to competition
and impressive bottom-line results should follow. Because of their importance, we
call value to the customer, variable cost, and the pace of innovation the
“fundamental metrics.”
Low power operation of electronic apparatus has becomeincreasingly desirable. Medical, remote data acquisition,power monitoring and other applications are good candidatesfor battery driven, low power operation. Micropoweranalog circuits for transducer-based signal conditioningpresent a special class of problems. Although micropowerICs are available, the interconnection of these devices toform a functioning micropower circuit requires care. (SeeBox Sections, “Some Guidelines for Micropower Designand an Example” and “Parasitic Effects of Test Equipmenton Micropower Circuits.”) In particular, trade-offs betweensignal levels and power dissipation become painful whenperformance in the 10-bit to 12-bit area is desirable.
The LTC®4099 high effi ciency USB power manager andLi-Ion/Polymer battery charger seamlessly managespower distribution from multiple sources in portableapplications. It is differentiated from other USB powermanagers by its bidirectional I2C port that allows the hostmicroprocessor to control and monitor all aspects of theUSB power management and battery charging processes.In addition, a programmable interrupt generation functionalerts the host microprocessor to changes in device statusand provides unprecedented control of power managementfunctions. This high degree of confi gurability allowspost-layout changes in operation, even changes in thefi eld, and it allows a single qualifi ed device to be usedin a variety of products, thus reducing design time andeasing inventory management.
In an increasing trend, telecommunications, networking,audio and instrumentation require low noise power supplies.In particular, there is interest in low noise, lowdropout linear regulators (LDO). These components powernoise-sensitive circuitry, circuitry that contains noisesensitiveelements or both. Additionally, to conserve power,particularly in battery driven apparatus such as cellulartelephones, the regulators must operate with low input-tooutputvoltages.1 Devices presently becoming availablemeet these requirements (see separate section, “A Familyof 20mVRMS Noise, Low Dropout Regulators”).
HIGH SPEED 8051 μC CORE
- Pipe-lined Instruction Architecture; Executes 70% of Instructions in 1 or 2
System Clocks
- Up to 25MIPS Throughput with 25MHz System Clock
- 22 Vectored Interrupt Sources
MEMORY
- 4352 Bytes Internal Data RAM (256 + 4k)
- 64k Bytes In-System Programmable FLASH Program Memory
- External Parallel Data Memory Interface – up to 5Mbytes/sec
DIGITAL PERIPHERALS
- 64 Port I/O; All are 5V tolerant
- Hardware SMBusTM (I2CTM Compatible), SPITM, and Two UART Serial
Ports Available Concurrently
- Programmable 16-bit Counter/Timer Array with 5 Capture/Compare
Modules
- 5 General Purpose 16-bit Counter/Timers
- Dedicated Watch-Dog Timer; Bi-directional Reset
CLOCK SOURCES
- Internal Programmable Oscillator: 2-to-16MHz
- External Oscillator: Crystal, RC, C, or Clock
- Real-Time Clock Mode using Timer 3 or PCA
SUPPLY VOLTAGE ........................ 2.7V to 3.6V
- Typical Operating Current: 10mA @ 25MHz
- Multiple Power Saving Sleep and Shutdown Modes
100-Pin TQFP (64-Pin Version Available)
Temperature Range: –40°C to +85°C
針對(duì)目前使用的RS232接口數(shù)字化B超鍵盤(pán)存在PC主機(jī)啟動(dòng)時(shí)不能設(shè)置BIOS，提出一種PS2鍵盤(pán)的設(shè)計(jì)方法。基于W78E052D單片機(jī)，采用8通道串行A/D轉(zhuǎn)換器設(shè)計(jì)了8個(gè)TGC電位器信息采集電路，電位器位置信息以鍵盤(pán)掃描碼序列形式發(fā)送，正交編碼器信號(hào)通過(guò)XC9536XL轉(zhuǎn)換為單片機(jī)可接收的中斷信號(hào)，軟件接收到中斷信息后等效處理成按鍵。結(jié)果表明，在滿足開(kāi)機(jī)可設(shè)置BIOS同時(shí)，又可實(shí)現(xiàn)超聲特有功能，不需要專門(mén)設(shè)計(jì)驅(qū)動(dòng)程序，接口簡(jiǎn)單，成本低。
Abstract: Aiming at the problem of the digital ultrasonic diagnostic imaging system keyboard with RS232 interface currently used couldn?蒺t set the BIOS when the PC boot， this paper proposed a design method of PS2 keyboards. Based on W78E052D microcontroller，designed eight TGC potentiometers information acquisition circuit with 8-channel serial A/D converter， potentiometer position information sent out with keyboard scan code sequentially.The control circuit based on XC9536 CPLD is used for converting the mechanical actions of the encoders into the signals that can be identified by the MCU， software received interrupt information and equivalently treatmented as key. The results show that the BIOS can be set to meet the boot， ultrasound specific functionality can be achieved at the same time， it does not require specially designed driver，the interface is simple and low cost.
設(shè)計(jì)一種基于AT89C52的語(yǔ)音錄放系統(tǒng)，利用單片機(jī)、ISD2560語(yǔ)音錄放器件、麥克風(fēng)、揚(yáng)聲器等元器件實(shí)現(xiàn)硬件電路的設(shè)計(jì)，并利用C51高級(jí)語(yǔ)言設(shè)計(jì)ISD2560器件控制字的寫(xiě)入和定時(shí)中斷程序。經(jīng)軟硬件調(diào)試，結(jié)果表明該系統(tǒng)錄放效果良好，具有一定的工程實(shí)用價(jià)值。
Abstract:
Voice recording and playback system based on AT89C52is designed in this paper.Using the single-chip microcomputer，voice recording and playback chip ISD2560，microphone and speaker to realize the hardware circuit design.Writing ISD2560control words and timing interrupt procedures are designed by C51advanced language.Through the hardware and software test,voice recording and playback system play better voice,and this system has some engineering practical values.
介紹基于ISA總線與KH-9300的數(shù)據(jù)采集板卡的設(shè)置，詳細(xì)說(shuō)明8254定時(shí)計(jì)數(shù)器及8259中斷控制器的結(jié)構(gòu)特點(diǎn)、工作方式、控制字等，探討中斷類(lèi)型、中斷處理程序、中斷矢量表及其填寫(xiě)。重點(diǎn)講述使用TorboC編寫(xiě)中斷服務(wù)程序的方法，應(yīng)注意的主要問(wèn)題及程序測(cè)試的結(jié)果。
Abstract:
The settings of KH-9300 data acquisition board based on the ISA bus is introduced,the structural characteristics,working methods,control characters of the timing counter 8254 and interruptioncontroller 8259 are explained in detail.The interruption type,interrupt handling programs,interruption vector table and its filling also are discussed.Further,great emphasis is put on the method of interrupt service program compiled by Torbo C,the main issues that should be noted,and the results of program testing.
