SanDisk安全数码卡毕业设计(论文)外文资料翻译

毕业设计(论文)外文资料翻译学 院： 计算机科学与工程学院 专 业： 计算机科学与技术 姓 名： 学 号： 外文出处： Product ManualVersion 2.2Document No. 80-13-00169 September (用外文写) 附 件： 1.外文资料翻译译文；2.外文原文。 指导教师评语： 签名： 年 月 日附件1：外文资料翻译译文SanDisk安全数码卡SD卡介绍这个安全数码卡是一种基于闪存的记忆卡,被专门设计来满足安全,生产能力,固有的性能和环境要求的新兴的音频和视频的消费者电子产品设备。SD卡的机制包括版权保护,符合SDMI的安全标准,速度更快,更高的记忆容量的能力。SD卡安全系统采用的相互影响新密码认证和“算法”,防止受到非法使用。一个不安全的访问对与使用者的内容也是可以利用的。SD卡的通信是基于一种先进的九针脚接口(时钟,命令,4xData和xPower线)下运作而设计,在一个低电压范围内。通信协议的定义是SD卡规格的一部分。SD卡主界面的常规操作支持多媒体卡。 换句话说,论述了前向兼容 多媒体卡被保存。 其实SD卡与多媒体卡的主要区别,在其初始化的过程。 SD卡规格最初是由松下电器公司、东芝公司和SanDisk公司定义的。目前,规格由安全电子协会控制。SanDisk SD卡被定义为和SD卡的物理规格是是兼容的SD卡接口便于整合成任何设计,不论微处理器的使用。为与现有的控制器,兼容性SanDisk SD卡提供除了以SD卡接口,交替通信协议,是基于SPI的标准。当前的SD卡提供1024亿字节的内存使用闪存芯片,设计了特别是用于大容量存储的应用。SD总线接口闪存模块SanDisk单芯片控制器数据输入输出控制 图1-1 SD卡的块图表1.1 范围本文档描述了关键特征和规格的SD卡,以及所需的本产品主机接口系统的信息。1.2 产品模型SD卡的型号和容量如表1 - 1所示。型号容量SDSDB-1616MBSDSDJ-3232 MBSDSDJ-6464 MBSDSDJ-128128 MBSDSDJ-256256 MBSDSDJ-512512MBSDSDJ-10241024 MBSDSDJ-20482048 MB表1-11.3 系统特征SD卡提供了以下特点:.2GB的存储容量.SD卡协议兼容的协议.支持SPI模式.针对便携式和固定 (版权保护申请担保)和不安全的数据存储。电压范围: .(CMD0 -基本通信,CMD15 ACMD41,CMD55):2.0-3.6V,。.其他指令和记忆访问:2.7-3.6V。.时钟的速度0-25 ?变量兆赫。.多达25个万位/秒的数据传输速率(使用4个并行数据线)。.最大的数据率多达10卡。.修正的错误记忆领域。.保护机制版权支持最高的SDMI标准.卡的密码协议(非所有模型)。.写保护功能使用机械的开关。.写保护特征(内置临时和永久性)。.探测(卡插入/迁移)。.应用程序特有的命令。.舒适的擦除机制。表1 - 2描述通信信道的性能表1-2SD卡的SD总线SD的SPI总线六根写通信总线三根连续的写数据总线错误保护数据转换可选择的不受保护的数据转换可用模式单一的或多个定向转换但一个或多个定向转换1.4 SD卡标准SD卡是完全相容于下列的SD卡实体层的规格标准:实体层的SD卡的系统规格说明1.10版本可以从以下方式的到规格说明书：SD卡协会53 Muckelemi St.邮政信箱189San Juan Bautista,95045-0189美国电话:831-623-2107 传真:831-623-2248 电子邮件:rcreechsdcard.org http:/www.sdcard.org1.5 功能描述SD卡SanDisk含有高标准、智能子系统如图1 1这个智能的(处理器)子系统提供了很多其它类型的记忆卡不具备的能力。这些功能包括:从细节独立主机擦除和编程闪存。复杂的系统管理缺陷(很类似系统发现在磁盘驱动器)。复杂的系统为差错恢复包括一个强大的纠错码(ECC)。对于低功率电源管理操作。1.5.1 闪存技术独立在一个IDE磁盘驱动器中，512字节的SD卡的扇区的大小都是一样的。为了写或读一个区域(或多个领域),主机软件简单的确保SD卡读或写命令。这命令包含地址。主机软件然后等待他们的命令去完成。主机软件不会涉及快闪记忆体细节的擦除,编程或读取信息。在未来的这是极其重要的作为闪光装置将会变的越来越复杂。由于SD卡使用一个智能的车载控制器、宿主系统软件不需要改变,新的快闪记忆体为基础。在其他支持的话,系统的SD卡今天就可以使用未来SanDisk SD卡一起建造新的闪光技术而无需修改或改变主机软件。1.5.2 缺陷和错误管理SD卡都包括一个复杂的缺陷和错误的管理体系。该系统是类似于系统发现在磁盘驱动器和在许多情况下提供改进。例如,磁盘驱动器通常都不会执行一个阅读一个写之后的数据,因为那会招致执行处罚。SD卡做下一个阅读在边缘写条件来验证资料是否正确地写自后。在有一个字节有缺陷的看见情况下,SD卡代替这个坏的字节,外加一张位在领域的标题。如果必要时,SD卡甚至会取代整个领域,与一个备用的部门。这是完全透明的主机和不消耗任何用户数据的空间。SD卡的软错误率规格远远超过磁盘驱动器的规格。在极为罕见的情况下一个读错误发生时,SD卡有创新的算法来恢复数据。这是类似于在使用磁盘驱动，但是它更复杂了。最后一道防线是要用一个强大的纠错码到正确的数据。如果ECC被用来恢复数据,有缺陷的比特位被替换为备用,以确保他们不造成任何未来的问题。这些缺陷和错误管理系统再加上固态建设给SD卡无与伦比的可靠性。1.5.3 版权保护详细描述的版权保护机制及相关安全的SD卡的命令可以在SD卡安全规格文档从SD卡协会找到。所有的SD卡安全相关的命令操作的数据传输模式。SDMI所定义的规范中,该数据内容就是保存在卡是保存已加密和它通过透明的和从卡。没有操作过的数据和没有约束的阅读数据在任何时间。每个资料封包联系在一起,比如(歌曲),这是存在未受保护的记忆有一种特别的数据保存在内存保护区域。对于任何访问(任何读写或擦除命令)从/到的数据,在受保护的区域。做一个认证的程序是卡”和“之间的连接装置,要么LCM(PC为例)或PD(移动设备中,例如SD玩家)。1.5.4 持久性SD卡有一个持久性的SanDisk规格各个部门的典型(阅读10万写逻辑部门是无限的)。这一数字远远超过通常要求是什么在几乎所有的应用程序的SD卡。例如, SD卡的经常使用在数字相机,手机,个人通信器、寻呼机和声音录音机将仅一小部分的总耐力的典型设备的寿命。例如,它将经过十多年的磨损面积在SD卡上的一个文件的任何尺寸(从512个字节来吗最大容量)被重写,3次每小时每天八小时,每一年365天。以典型的应用中,耐力极限不是任何实际的关注广大用户。1.5.5 穿平Wear-leveling是一种内在的一部分使用的功能,消除池NAND SD记忆。SD卡的支持穿一级命令操作维护作为NOP向后兼容性与现有的软件公用事业。1.5.6 使用擦除指令部门或组织的擦除(的能力)指令提供了极大地增加写性能的SD卡。一旦一个部分已经擦除,用擦除指令部分写给那将会快得多。这是因为一个正常的写操作,包括一个独立的擦写部门。1.5.7 自动休眠模式一个独有的特点的SD卡(和其它SanDisk SanDisk产品进口和出口)是自动进入或退出睡眠模式。在完成后, 在5msec内没有收到下一步的命令SD卡将进入睡眠模式以节约用电。为这发生主机没有采取任何行动。在大多数系统,SD卡在睡眠模式,只有当主机访问时才被唤醒,从而节约电源。当宿主已准备好去访问SD卡和睡眠模式,它是在发出的任何命令之后能使其退出睡眠模式并产生回应。1.5.8 热插拔主机的要求是支持热插但要通过连接器获得支持。连接器制造商将提供连接器产品,有权柄针脚的时间还不够长,无法接触前制作与动力另一个针脚。请参阅连接器数据表为更多的细节。这个方法是用于PCMCIA相似MMCA装置,以允许热插入。1.5.9 SD Card-SD总线模式下面的章节提供有价值的信息对SC的卡片上,装在SD总线模式。1.5.9.1 SD卡符合的标准SD卡是完全遵守SD卡V1.01物理层标准规格。卡规格数据寄存器的构造是服从CSD1.0版本的。1.5.9.2 谈判操作条件SD卡支持的操作条件验证序列中定义的SD卡标准规格。SD卡主机应该定义一个工作电压范围,从而不支持的SD卡将本身存在一种停滞状态,而忽视任何总线式通信。使SD卡从停滞状态出来的唯一的方法是给其上电再放电。此外主机可明确地利用GO_INACTIVE_STATE命令把卡片处于停滞状态。1.5.9.3 卡采集和识别SD卡的总线是一单个主机(SD卡)和multi-slaves主机应用程序(卡)总线。时钟和电源线是常见的卡总线。在识别过程,主机通过自己的命令行访问每一张卡片另行规定。SD卡的CID登记的二级管卡是用一种独特的识别数字,它被用于在识别程序。此外,SD卡的主机可读卡片的CID注册使用READ_CID SD卡的命令。CID登记是程序在制造平台上对SD卡的测试和格式化程序。SD卡主机只能阅读这个注册并不能写。一个内部拉电阻器在DAT3线可以用于检测(插入/迁移卡)。本电阻器ACMD42在数据传输(使用)时可以被断开。额外的实用卡检测方法中都能找到SD物理规格的应用笔记所给出的现代化进程。1.5.9.4 卡状态这张卡状态分为以下两大领域:卡状态储存在一个32位的状态寄存器中，而这个寄存器是用来回应主机命令的。状态寄存器提供有关卡的现状和完成编码在过去的主机的命令。这张卡状态可以通过SEND_STATUS这个命令显式地读。被储存在512位，回应被请求的主机利用SD_STATUS(ACMD13)的命令命令。它作为一个单独的数据块。SD_Status包括扩展的状态位，这些位关系到BUS_WIDTH、安全相关位和未来中的具体应用。1.5.9.5 内存阵列分区SD卡数据传输的基本单位是一个字节。所有命令一个块大小的的数据转移操作需要总是定义块长度尺寸为字节的整数倍。一些特殊功能需要其他的分隔尺寸。图1 - 2显示内存阵列分区。为初始块的指令, 使用了以下定义:块-这个单位是涉及块初始化读和写的命令。 它的规模是当主机发送块命令时所转移的字节的数量。一个块的大小是可编程的或是固定。在CSD中存储了关于块得大小和可编程的信息。可擦除单元的间隔尺寸一般和初始化命令是不同的扇区-这个单位,是涉及擦除的命令。它的规模被擦除的部分的块的大小。每台设备扇区的大小是固定的。关于扇区大小的信息存储在CSD中。写保护的设备, 使用了包括以下定义: WP组最小的单元可能被分成独立的写保护。它的规模是被一位写保护的组的数量。对每个设备来说WP-组的大小是固定的。有关组信息被存储在CSD中。WP组一WP组二第二扇区第一扇区第三扇区第n扇区第一扇区第n扇区SD记忆卡块n块0保护区块n块0图1-2内存阵列分区1.5.9.6 SD卡的读写操作SD卡支持读写两种模式，如图所示多块模式记忆扇区记忆扇区记忆扇区 记忆扇区记忆扇区 记忆扇区记忆扇区单模块记忆扇区记忆扇区记忆扇区 记忆扇区记忆扇区 记忆扇区记忆扇区 图1-3数据转换格式单块模式在这种模式下主机在一个预定义的长度下读或写一个数据块。这些数据的块传输是16位的CRC被保护的，CRC是在被接受单元发送和检查时产生的。读操作的块长度是由设备扇区的大小(512个字节)所限制的能和单字节一样大小。不允许错位的。每一个数据块必须包含一个单独的物理领域。块长度为写操作必须相同的扇区的大小和启动地址排列成一个部门的界限。多个块模式该机型是类似于单块模式,但主机可读/写多个数据块(都是相等的长度),在连续内存地址中会被储存或检索。操作终止以终止传输命令。错位与块长限制也适用于多块和单块一致1.5.9.7数据传输速率SD卡的可操作使用的是一个单独的数据)或四线(DAT0数据线(DAT0-DAT3)数据转让。最大的数据转移率为一个单一的数据行, 第二是25-Mb 100-Mb每秒每(12 MB)使用4个数据传输线。1.5.9.8 数据保护在卡片每个部门都是保护用误差修正代码(ECC)。人们对错误校正码的生成(在你的记忆卡)的时候这些扇区都被书面记录并且验证了在数据被读取。如果缺陷被发现后,数据被提前纠正送往主机。1.5.9.9 擦除SD卡最小的可擦写单元是一个扇区。为了加快擦除的速度，多个扇区可以同时被擦除。为了促进选择第一个开始的命令是被第二个命令和最后一个指令所允许的，所有范围之内的扇区将被选为擦除。1.5.9.10 写保护两个卡标准的写保护可供选择:临时和永久性的。两者皆可设置使用PROGRAM_CSD命令(见下文)。 永久写保护点,一旦被创立,就不能被清除。这一特点在SD卡实现控制器固件和不与物理编译OTP单元。注意:使用写保护(工作)开关位于卡的边上,以防止主机在卡上写或者擦除数据。在CSD中WP开关永远不会对临时的或永久的WP位产生影响。1.5.9.1 复制位在CSD寄存器中SD卡的内容可以作为原件或副本被使用。一旦被拷贝(标记成一个副本),它不能被清除。复制位(SD卡是在测试过程中,编程格式化生产层)作为一个副本。SD卡可以购买与复制或位元(复印件)清除,并说明卡是一个控制。此功能是实现控制器在SD卡固件而不能用一种物理编译OTP单元。1.5.9.12 CSD寄存器D卡所有的配置信息储存在CSD寄存器中。寄存器的每个字节包含制造商数据和两个最小有效字节包含主机控制数据,卡复制、写保护和用户文件格式的想法。主机可以读取CSD注册并改变主机使用SEND_CSD控制和PROGRAM_CSD命令。1.5.10 SD Card-SPI模式该模式为SD卡的一个次要通讯协议。这种模式的一个子集的SD卡协议,一个SPI设计与沟通渠道,普遍存在于摩托罗拉(和最近一些其他供应商的)微控制器。1.5.10.1 谈判操作条件在操作条件谈判的功能支持的SD卡总线的方法,在利用SPI模式READ_OCR(CMD58)命令。 主机应工作在2.7 36伏特有效电压范围内的卡片或者把卡在GO_INACTIVE停滞状态通过发送命令给卡。1.5.10.2 卡采集和识别主机必须通过总线知道当前卡的链接数量。通过CS信号选择是做具体卡(CD / DAT3)。在内部元器件库中的上拉电阻CD / DAT3线可以用于卡检测(插入/迁移)。额外的实用卡检测方法,可以在SD物理规格中发现。1.5.10.3 卡状态在SPI模式,只有16位(包括错误相关模式),可以去读SPI的32位的SD卡的状态。使用ACMD13可以读的SD卡的状态,在SD总线模式下也一样。1.5.10.4 内存阵列分区记忆在模式划分,相当于SD SPI总线模式。所有读和写命令是在1.5.9.5中给出的有限制的可寻址的位。1.5.10.5 读和写操作支持在SPI模式、单体及多块数据传输模式。1.5.10.6 数据传输速率在该模式,在每个方向只使用一根数据线。该模式的数据传输速率是相同的标准差主机模式的数据转移率只使用一个数据行(每秒多达25 Mbits)。1.5.10.7 SD卡的数据保护同SD卡模式。1.5.10.8 擦除同SD卡模式。1.5.10.9 写保护同SD卡模式。1.5.10.10 版权保护同SD卡模式. .附件2：外文原文（复印件）1. introduction to the SD card. Introduction to the SDThe Secure Digital Card is a flash-based memory card that is specifically designed to meet the security, capacity,performance and environmental requirements inherent in newly emerging audio and video consumer electronicdevices. The SD Card includes a copyright protection mechanism that complies with the security of the SDMIstandard, and is faster and capable of higher Memory capacity. The SD Card security system uses mutualauthentication and a “new cipher algorithm” to protect from illegal usage of the card content. A non-secured accessto the users own content is also available. The physical form factor, pin assignment and data transfer protocol areforward compatible with the SD Card, with some additions.The SD Card communication is based on an advanced nine-pin interface (Clock, Command, 4xData and 3xPowerlines) designed to operate in a low voltage range. The communication protocol is defined as part of this specification. The SD Card host interface supports regular MultiMediaCard operation as well. In other words, MultiMediaCard forward compatibility was kept. Actually the main difference between SD Card and MultiMediaCard is the initialization process. The SD Card specifications were originally defined by MEI (Matsushita Electric Company), Toshiba Corporation and SanDisk Corporation. Currently, the specifications arecontrolled by the Secure Digital Association (SDA). The SanDisk SD Card was designed to be compatible with theSD Card Physical Specification.The SD Card interface allows for easy integration into any design, regardless of microprocessor used. For compatibility with existing controllers, the SanDisk SD Card offers, in addition to the SD Card interface, an alternate communication protocol, which is based on the SPI standard.The current SD Card provides up to 1024 million bytes of memory using flash memory chips, which were designedespecially for use in mass storage applications. In addition to the mass storage specific flash memory chip, the SDCard includes an on-card intelligent controller which manages interface protocols,securityalgorithms for copyrightprotection, data storage and retrieval, as well as Error Correction Code (ECC)algorithms, defect handling anddiagnostics, power management and clock control.Figure 1-1. SD Card Block Diagram1.1. ScopeThis document describes the key features and specifications of the SD Card, as well as the information required tointerface this product to a host system.1.2. Product ModelsThe SD Card is available in the capacities shown in Table 1-1.1.3. System FeaturesThe SD Card provides the following features: Up to 2-GB of data storage. SD Card protocol compatible. Supports SPI Mode. Targeted for portable and stationary applications for secured (copyrights protected) and non-secureddata storage. Voltage range: Basic communication (CMD0, CMD15, CMD55, ACMD41): 2.0-3.6V. Other commands and memory access: 2.7-3.6V. Variable clock rate 0-25 MHZ. Up to 25 MB/sec data transfer rate (using 4 parallel data lines). Maximum data rate with up to 10 cards. Correction of memory field errors. Copyrights Protection MechanismComplies with highest security of SDMI standard.Introduction to the SD CardSanDisk Secure Digital (SD) Card Product Manual, Rev. 2.2 2004 SANDISK CORPORATION 1-3 Password Protected of Cards (not on all models). Write Protect feature using mechanical switch. Built-in write protection features (permanent and temporary). Card Detection (Insertion/Removal). Application-specific commands. Comfortable erase mechanism.The performance of the communication channel is described in Table 1-2.1.4. SD Card StandardSanDisk SD Cards are fully compatible with the following SD Card Physical Layer Specification standard:The SD Card Physical Layer System Specification, Version 1.10This specification may be obtained from:SD Card Association53 Muckelemi St.P.O. Box 189San Juan Bautista, CA 95045-0189USAPhone: 831-623-2107Fax: 831-623-2248Email: rcreechsdcard.orghttp:/www.sdcard.org1.5. Functional DescriptionSanDisk SD Cards contain a high level, intelligent subsystem as shown in Figure 1-1. This intelligent (microprocessor) subsystem provides many capabilities not found in other types of memory cards. These capabilities include: Host independence from details of erasing and programming flash memory. Sophisticated system for managing defects (analogous to systems found in magnetic disk drives). Sophisticated system for error recovery including a powerful error correction code (ECC). Power management for low power operation.1.5.1. Flash Technology IndependenceThe 512-byte sector size of the SD Card is the same as that in an IDE magnetic disk drive. To write or read a sector(or multiple sectors), the host computer software simply issues a Read or Write command to the SD Card. Thiscommand contains the address. The host software then waits for the command to complete. The host software does not get involved in the details of how the flash memory is erased, programmed or read. This is extremely importantas flash devices are expected to get more and more complex in the future. Because the SD Card uses an intelligent on-board controller, the host system software will not require changing as new flash memory evolves. In other words, systems that support the SD Card today will be able to access future SanDisk SD Cards built with new flash technology without having to update or change host software.1.5.2. Defect and Error ManagementSD Cards contain a sophisticated defect and error management system. This system is analogous to the systems found in magnetic disk drives and in many cases offers enhancements. For instance, disk drives do not typically perform a read after write to confirm the data is written correctly because of the performance penalty that would be incurred. SD Cards do a read after write under margin conditions to verify that the data is written correctly. In the rare case that a bit is found to be defective, SD Cards replace this bad bit with a spare bit within the sector header. If necessary, SD Cards will even replace the entire sector with a spare sector. This is completely transparent to the host and does not consume any user data space.The SD Cards soft error rate specification is much better than the magnetic disk drive specification. In the extremely rare case a read error does occur, SD Cards have innovative algorithms to recover the data. This is similar to using retries on a disk drive but is much more sophisticated. The last line of defense is to employ a powerful ECC to correct the data. If ECC is used to recover data, defective bits are replaced with spare bits to ensure they do not cause any future problems. These defect and error management systems coupled with the solid-state construction give SD Cards unparalleled reliability.1.5.3. Copyright ProtectionA detailed description of the Copyright Protection mechanism and related security SD Card commands can be found in the SD Card Security Specification document from the SD Card Association. All SD Card security related commands operate in the data transfer mode.As defined in the SDMI specification, the data content that is saved in the card is saved already encrypted and it passes transparently to and from the card. No operation is done on the data and there is no restriction to read the data at any time. Associated with every data packet (song, for example) that is saved in the unprotected memory there is a special data that is saved in a protected memory area. For any access (any Read, Write or Erase command) from/to the data in the protected area. For an authentication procedure is done between the card and the connected device, either the LCM (PC for example) or the PD (portable device, such as SD player). After the authentication process passes, the card is ready to accept or give data from/to the connected device. While the card is in the secured mode of operation (after the authentication succeeded) the argument and the associated data that is sent to the card or read from the card are encrypted. At the end of the Read, Write or Erase operation, the card gets out automatically of its secured mode. 1.5.4. EnduranceSanDisk SD Cards have an endurance specification for each sector of 100,000 writes typical (reading a logical sector is unlimited). This far exceeds what is typically required in nearly all applications of SD Cards. For example, even very heavy use of the SD Card in digital still cameras, cellular phones, personal communicators, pagers and voice recorders will use only a fraction of the total endurance over the typical devices lifetime. For instance, it would take over 10 years to wear out an area on the SD Card on which a file of any size (from 512 bytes to maximum capacity) was rewritten 3 times per hour, 8 hours a day, 365 days per year. With typical applications, the endurance limit is not of any practical concern to the vast majority of users.1.5.5. Wear LevelingWear-leveling is an intrinsic part of the Erase Pooling functionality of SD using NAND memory. The SD CardsWear Level command is supported as a NOP operation to maintain backward compatibility with existing softwareutilities.1.5.6. Using the Erase CommandThe Erase (sector or group) command provides the capability to substantially increase the write performance of the SD Card. Once a sector has been erased using the Erase command, a write to that sector will be much faster. This is because a normal write operation includes a separate sector erase prior to write.1.5.7. Automatic Sleep ModeA unique feature of the SanDisk SD Card (and other SanDisk products) is automatic entrance and exit from sleepmode. Upon completion of an operation, the SD Card will enter the sleep mode to conserve power if no further commands are received within 5msec. The host does not have to take any action for this to occur. In most systems, the SD Card is in sleep mode except when the host is accessing it, thus conserving power.When the host is ready to access the SD Card and it is in sleep mode, any command issued to the SD Card willcause it to exit sleep and respond.1.5.8. Hot InsertionSupport for hot insertion will be required on the host but will be supported through the connector. Connectormanufacturers will provide connectors that have power pins long enough to be powered before contact is made with the other pins. Please see connector data sheets for more details. This approach is similar to that used in PCMCIA and MMCA devices to allow for hot insertion.1.5.9. SD CardSD Bus ModeThe following sections provide valuable information on the SC Card in SD Bus mode.1.5.9.1. SD Card Standard ComplianceThe SD Card is fully compliant with SD Card Physical Layer Standard Specification V1.01. The structure of the Card Specific Data (CSD) register is compliant with CSD Structure 1.0.1.5.9.2. Negotiating Operation ConditionsThe SD Card supports the operation condition verification sequence defined in the SD Card standard specifications.Should the SD Card host define an operating voltage range, which is not supported by the SD Card it will put itself in an inactive state and ignore any bus communication. The only way to get the card out of the inactive state is by powering it down and up again.In Addition the host can explicitly send the card to the inactive state by using the GO_INACTIVE_STATEcommand.1.5.9.3. Card Acquisition and IdentificationThe SD Card bus is a single master (SD Card host application) and multi-slaves (cards) bus. The Clock and Power lines are common to all cards on the bus. During the identification process, the host accesses each card separately through its own command lines. The SD Cards CID register is pre-programmed with a unique card identification number, which is used during the identification procedure.In addition, the SD Card host can read the cards CID register using the READ_CID SD Card command. The CID register is programmed during the SD Card testing and formatting procedure, on the manufacturing floor. The SD Card host can only read this register and not write to it.An internal pull-up resistor on the DAT3 line may be used for card detection (insertion/removal). The resistor canbe disconnected during data transfer (using ACMD42). Additional practical card detection methods can be found in SD Physical Specifications Application Notes given by the SDA.1.5.9.4. Card StatusThe card status is separated into