DS1302中文手册DS1302 是一款高性能、低功耗的实时时钟芯片，被广泛应用于各种需要准确计时的电子设备中。
一、DS1302 的基本特性1、实时时钟功能能够精确记录年、月、日、时、分、秒等时间信息。
2、低功耗设计在电池供电的情况下，仍能保持长时间的计时准确性。
3、数据存储具备 31 字节的非易失性静态 RAM，可用于存储一些关键数据。
4、简单的接口通过串行接口与微控制器进行通信，易于集成到系统中。
二、DS1302 的引脚功能1、 Vcc1 和 Vcc2Vcc1 是主电源引脚，Vcc2 是备用电源引脚。
当主电源正常供电时，芯片使用 Vcc1 供电；当主电源断电时，自动切换到 Vcc2（通常为电池）以保持时钟运行。
2、 GND接地引脚。
3、 CLK时钟输入引脚，用于同步数据传输。
4、 I/O数据输入/输出引脚。
5、 RST复位引脚，高电平有效。
三、DS1302 的通信协议DS1302 采用串行通信方式，通信数据以字节为单位进行传输。
1、起始位在每个字节传输开始时，RST 引脚被置为高电平，启动通信过程。
2、控制字节首先发送一个控制字节，用于指定后续操作是读操作还是写操作，以及要操作的寄存器地址。
3、数据字节根据控制字节的指示，接着传输数据字节。
4、停止位在传输完一个字节的数据后，将 RST 引脚置为低电平，结束本次通信。
四、DS1302 的寄存器1、时钟/日历寄存器包括年、月、日、时、分、秒等寄存器，用于存储时间信息。
2、控制寄存器用于设置时钟的工作模式，如是否开启振荡器、是否进行写保护等。
3、充电寄存器用于控制备用电源的充电特性。
4、 31 字节的 RAM 寄存器用于用户自定义数据存储。
五、DS1302 的初始化与设置在使用 DS1302 之前，需要进行初始化设置，包括设置初始时间、开启振荡器、关闭写保护等操作。
1、写入初始时间通过串行通信将准确的初始时间写入到相应的时钟/日历寄存器中。
2、开启振荡器将控制寄存器的相应位设置为 1，使振荡器开始工作。
DevicesPart Number HDSP-ColorDescriptionFront View0781High-Efficiency Red Numeric, Right Hand DP A 0782Low Power Numeric, Left Hand DP B 0783Over Range ±1C 0784HexadecimalD 0791High-Efficiency Red Numeric, Right Hand DP A 0792High Brightness Numeric, Left Hand DP B 0793Over Range ±1C 0794HexadecimalD 0881YellowNumeric, Right Hand DP A 0882Numeric, Left Hand DP B 0883Over Range ±1C 0884HexadecimalD 0981High-Performance GreenNumeric, Right Hand DP A 0982Numeric, Left Hand DP B 0983Over Range ±1C 0984HexadecimalDHDSP-078x HDSP-079x HDSP-088x HDSP-098xFeatures• Three Character Options Numeric, Hexadecimal, Over Range• Three ColorsHigh Efficiency Red, Yellow,High Performance Green• 4x 7 Dot Matrix Character • High Efficiency Red, Yellow and High Performance Green • Two High Efficiency Red OptionsLow Power, High Brightness • Performance Guaranteed Over Temperature• High Temperature Stabilized • Memory Latch/Decoder/DriverTTL Compatible• Categorized for Luminous IntensityDescriptionThese standard solid state displays have a 7.4 mm (0.29 inch) dot matrix character and an on-board IC with data memory latch/decoder and LED drivers in a glass/ceramic package.The hermetic HDSP-078x,-079x/-088x displays utilize a solder glass frit seal. The HDSP-098X displays utilize an epoxy glass-to-ceramic seal.The numeric devices decode posi-tive BCD logic into characters “0-9,” a “–” sign, decimal point,and a test pattern. Thehexadecimal devices decodeGlass/Ceramic Numeric and Hexadecimal Displays for Industrial Applications Technical Datapositive BCD logic into 16characters, “0-9, A-F.” An input is provided on the hexadecimal devices to blank the display (all LEDS off) without losing the contents of the memory.The over range device displays “±1” and right hand decimal point and is typically driven via external switching transistors.COUNTRY CODEPackage DimensionsAbsolute Maximum RatingsNotes:1. The nominal thermal resistance of a display mounted in a socket that is soldered onto a printed circuit board isRθJA=50°C/W/device. The device package thermal resistance is RθJ-PIN = 15°C/W/device. The thermal resistance device pin-to-ambient through the PC board should not exceed 35°C/W/device for operation up to T A = +100°C.2. Voltage values are with respect to device ground, pin 6.3. These displays are categorized for luminous intensity with the intensity category designated by a letter code located on the back ofthe display package. Case temperature of the device immediately prior to the light measurement is equal to 25°C.Electrical/Optical Characteristics T A = –55°C to +100°CNotes:4. The luminous intensity at a specific operating ambienttemperature, I v(T A), may be approximated from the following exponential equation: I v(T A)=I v(25°C) e[k(T-25°C)].Device KHDSP-078 Series–0.0131/°CHDSP-079x SeriesHDSP-088x Series–0.0112/°CHDSP-098x Series–0.0104/°C 5. The dominant wavelength, λd, is derived from the CIE chroma-ticity diagram and represents the single wavelength whichdefines the color of the device.6. The HDSP-088X and HDSP-098X series devices are categor-ized as to dominant wavelength with the category designated by a number on the back of the display package.7. All typical values at V CC = 5.0 V and T A = 25°C.Operational ConsiderationsElectricalThese devices use a modified4x7 dot matrix of light emitting diodes to display decimal/ hexadecimal numeric informa-tion. The high efficiency red and yellow displays use GaAsP/GaP LEDs and the high performance green displays use GaP/GaP LEDs. The LEDs are driven by constant current drivers, BCD information is accepted by the display memory when the enable line is at logic low and the data islatched when the enable is atlogic high. Using the enable pulsewidth and data setup and holdtimes listed in the RecommendedOperating Conditions allows datato be clocked into an array ofdisplays at a 6.7MHz rate.The decimal point input is activelow true and this data is latchedinto the display memory in thesame fashion as the BCD data.The decimal point LED is drivenby the on-board IC.The blanking control input on thehexadecimal displays blanks(turns off) the displayedinformation without disturbingthe contents of display memory.The display is blanked at aminimum threshold level of 2.0volts. When blanked, the displaystandby power is nominally 250mW at T A = 25°C.The ESD susceptibility of the ICdevices is Class A of MIL-STD-883 or Class 2 of DOD-STD-1686and DOD-HDBK-263.AMechanicalThese displays are hermetically sealed for use in environments that require a high reliability device. These displays are designed and tested to meet a helium leak rate of5x10-8cc/sec.These displays may be mounted by soldering directly to a printed circuit board or insertion into a socket. The lead-to-lead pin spacing is 2.54 mm (0.100 inch) and the lead row spacing is 15.24 mm (0.600 inch). These displays may be end stacked with 2.54 mm (0.100 inch) spacing between outside pins of adjacent displays. Sockets such as Augat 324-AG2D (3 digits) or Augat 508-AG8D (one digit, right anglemounting) may be used.The primary thermal path forpower dissipation is through thedevice leads. Therefore, to insurereliable operation up to anambient temperature of +100°C,it is important to maintain abase-to-ambient thermalresistance of less than35°C watt/device as measured ontop of display pin 3.For further information onsoldering and post soldercleaning, see Application Note1027, Soldering LEDComponents.PreconditioningThese displays are 100% pre-conditioned by 24 hour storage at125°C, at 100°C for the HDSP-098x Series.Contrast EnhancementThese display devices aredesigned to provide an optimumON/OFF contrast when placedbehind an appropriate contrastenhancement filter. For furtherinformation on contrastenhancement, see ApplicationNote 1015, ContrastEnhancement for LEDDisplays.Over Range DisplayThe over range devices display“±1” and decimal point. Thecharacter height and packageconfiguration are the same as thenumeric and hexadecimaldevices. Character selection isobtained via external switchingtransistors and current limitingresistors.Absolute Maximum RatingsDescription Symbol Min Max Unit Storage Temperature, Ambient T S–65+125°C Operating Temperature, Ambient T A–55+100°C Forward Current, Each LED I F10mA Reverse Voltage, Each LED V R5VPackage DimensionsLuminous Intensity per LED(Digit Average) at T= 25°C Figure 3. Typical Driving Circuit.Notes:0: Line switching transistor in Figure 7 cutoff.1: Line switching transistor in Figure 7 saturated.X: ‘don’t care.’Electrical Characteristics T A = –55°C to +100°CColor Bin Limits (Dominant Wavelength)Note:Bin categories are established for classification of products. Productsmay not be available in all bin categories. Please consult your localAgilent Technologies representative./semiconductorsFor product information and a complete list ofdistributors, please go to our web site.For technical assistance call:Americas/Canada: +1 (800) 235-0312 or(916) 788-6763Europe: +49 (0) 6441 92460China: 10800 650 0017Hong Kong: (+65) 6756 2394India, Australia, New Zealand: (+65) 6755 1939Japan: (+81 3) 3335-8152 (Domestic/Interna-tional), or 0120-61-1280 (Domestic Only)Korea: (+65) 6755 1989Singapore, Malaysia, Vietnam, Thailand,Philippines, Indonesia: (+65) 6755 2044Taiwan: (+65) 6755 1843Data subject to change.Copyright © 2004 Agilent Technologies, Inc.Obsoletes 5964-6390EJuly 14, 20045988-2261EN。
