SPI协议简介

井木轩

SPI，是英语Serial Peripheral interface的缩写，顾名思义就是串行外围设备接口。SPI，是一种高速的，全双工，同步的通信总线，并且在芯片的管脚上只占用四根线，节约了芯片的管脚，同时为PCB的布局上节省空间，提供方便，正是出于这种简单易用的特性，现在越来越多的芯片集成了这种通信协议，比如P89LPC900. 

SPI，是一种高速的，全双工，同步的通信总线，其工作模式有两种：主模式和从模式，无论那种模式，都支持3Mbit/s的速率，并且还具有传输完成标志和写冲突保护标志。到目前为止，我使用过的具有SPI总线的器件，就是存储芯片Eprom：at25128，在使用过程中，发现的确是有这种总线的优点。下面以P89LPC900单片机的SPI总线来解释SPI总线的通用使用规则。

LPC900单片机的SPI接口主要由4个引脚构成：SPICLK、MOSI、MISO及/SS，其中SPICLK是整个SPI总线的公用时钟，MOSI、MISO作为主机，从机的输入输出的标志，MOSI是主机的输出，从机的输入，MISO是主机的输入，从机的输出。/SS是从机的标志管脚，在互相通信的两个SPI总线的器件，/SS管脚的电平低的是从机，相反/SS管脚的电平高的是主机。在一个SPI通信系统中，必须有主机。

SPI总线可以配置成单主单从，单主多从，互为主从。今以互为主从模式作为讲解：

要进行SPI互为主从操作，必须遵照以下步骤： 

1 对A、B进行初始化，均设为主机（需要进行以下操作）。 

a) SPI端口初始化为准双向。 

b) SPCTL配置为0x50，SSIG=0，SPEN=1，MSTR=1。 

c) 清除SPSTAT中的SPIF及WCOL标志位为0。 

d) 如果需要使用SPI中断，可使能相应中断位。 

井木轩

<font size="4">&nbsp;&nbsp; 2 <span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">将</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">A</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">上一个引脚连接到</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">B</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">的</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">/SS</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">引脚上，然后拉低</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">/SS</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">，可将</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">B</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">强行置为从机模式，同时</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">B</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">机会发生以下变化：</span></font><font size="4"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">&nbsp;<br/><br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; a) B</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">机的</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">MSTR</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">位自动清</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">0</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">。</span></font><font size="4"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">&nbsp;<br/><br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; b) B</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">机的</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">MOSI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">及</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">SPICLK</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">强行变为输入模式，</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">MISO</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">则变为输出模式。</span></font><font size="4"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">&nbsp;<br/><br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; c) B</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">机</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">SPIF</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">位置位。</span></font><font size="4"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">&nbsp;<br/><br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; d) </span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">如果</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">SPI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">中断使能，</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">B</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">机将执行</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">SPI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">中断服务程序。</span></font><font size="4"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">&nbsp;<br/><br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 3 B</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">机可设置为查询接收或中断接收方式，以时刻准备接收由</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">A</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">机发送过来的数据，要使</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">B</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">机恢复为主机，必须完整执行步骤</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">1</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">。</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma"> </span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">本示例中，通过两块</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">DP932 </span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">实验板构成了</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma">SPI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma">互为主从测试系统。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma"> <?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o:p></o:p></span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">程序中应注意的问题：</span></font><font size="4"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">&nbsp;<br/><br/>&nbsp;&nbsp;&nbsp;&nbsp;</span></font>

井木轩

&nbsp;&nbsp; 1 <span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">程序中应注意对首次拉低</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SS</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">引脚进行处理：当</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">A</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">机首次通过</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">B_SS</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">将</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">B</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">机设置为从机后，从机的</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SBIF</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">位会置位（会被认为完成一次传输），如果这之前，使能了</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SPI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">中断，则从机则会执行相应的中断服务程序（本示例程序中，当</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">B</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">机的</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SS</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">引脚被拉为低电平，</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">B</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">机的</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SBIF</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">首次置位进行处理）。</span><font size="4"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">&nbsp;<br/><br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 2 </span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">关于从机恢复为主机的问题：互为主从模式中，当</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">B</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">机被</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">A</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">机设置为从机后，</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">CPCTL</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">寄存器中</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">MSTR</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">位被清除为</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">0</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">，且</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SPIF</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">被置</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">1</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">，</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">MOSI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">和</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SPICLK</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">强制变为输入模式，</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">MISO</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">强制变为输出模式。要想恢复为主机，必须执行以下操作：</span></font><font size="4"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">&nbsp;<br/><br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; a) </span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">将</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">MSTR</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">位置</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">1</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">，</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SPIF</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">位清</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">0</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">。</span></font><font size="4"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">&nbsp;<br/><br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; b) </span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">将</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">MOSI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">，</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SPICLK</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">，</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">MISO</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">及</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SS</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">重新恢复为准双向口。</span></font><font size="4"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">&nbsp;<br/><br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; c) </span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">在</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">a)</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">、</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">b)</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">之前，需要注意将</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">B_SS</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">拉高，如果其一直为低电平，即使完成</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">a)</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">、</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">b)</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">操作，也会将</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">B</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">机重新设置为从机。</span></font><font size="4"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">&nbsp;<br/><br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 3 </span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">在</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SPI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">总线的使用过程中，可以通过</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">DORD</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">（</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SPI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">数据顺序选择位），</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">CPOL</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">（</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SPI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">时钟极性选择位），</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">CPHA</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">（</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA"> SPI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">时钟相位选择位）控制主</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">/</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">从机传输格式。对于本实验，可以忽略这些位的影响，但是在使用一些其他</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SPI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">器件时，必须根据从器件数据手册的要求，对</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SPI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">数据的传输顺序，</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SPI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">的时钟极性，及</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SPI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">的时钟相位进行正确的设置。</span></font><font size="4"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">&nbsp;<br/><br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 4 </span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">一些</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SPI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">的应用系统，由于硬件的设计并不是很合理，所以有时</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SPI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">通信不正常（传输数据出错，或其他情况），你可以试着降低</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SPI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">总线的传输速率，或者调节一些</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: Tahoma; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">SPI</span><span style="FONT-SIZE: 10.5pt; COLOR: #333333; FONT-FAMILY: 宋体; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: Tahoma; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">时钟极性及相位，以使传输稳定。</span></font>