实例——usb设备驱动设计（上）--山野村夫.htm

USB驱动设计的步骤和主要程序框架

                              lang=EN-US>3</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">．</SPAN><SPAN 
                              lang=EN-US>3V</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的调整器用于模拟收发器的供电。该电压还作</SPAN><SPAN 
                              lang=EN-US><SPAN style="mso-spacerun: yes">&nbsp; 
                              </SPAN></SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">为输出连接到外部</SPAN><SPAN 
                              lang=EN-US>1</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">．</SPAN><SPAN 
                              lang=EN-US>5k</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">Ω的上拉电阻。</SPAN><SPAN 
                              lang=EN-US>PDIUSBD 12</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">提供集成</SPAN><SPAN 
                              lang=EN-US>1</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">．</SPAN><SPAN 
                              lang=EN-US>5k</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">Ω上拉电阻的</SPAN><SPAN 
                              lang=EN-US><SPAN style="mso-spacerun: yes">&nbsp; 
                              </SPAN>SoftConnect</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">技术。</SPAN></P>
                              <P class=MsoNormal 
                              style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0"><SPAN 
                              lang=EN-US><o:p>&nbsp;</o:p></SPAN></P>
                              <P class=MsoNormal 
                              style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0"><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">·</SPAN><SPAN 
                              lang=EN-US>PLL</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">：片上集成了</SPAN><SPAN 
                              lang=EN-US>6MHz</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">到</SPAN><SPAN 
                              lang=EN-US>48MHz</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">时钟乘法，允许使用低成本的</SPAN><SPAN 
                              lang=EN-US>6MHz</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">晶振，</SPAN><SPAN 
                              lang=EN-US>EMI<SPAN 
                              style="mso-spacerun: yes">&nbsp; 
                              </SPAN></SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">也由于使用低频晶振而降低。</SPAN><SPAN 
                              lang=EN-US>PLL</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的使用不需要外部元件。</SPAN></P>
                              <P class=MsoNormal 
                              style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 15.75pt; mso-char-indent-count: 1.5"><SPAN 
                              lang=EN-US><o:p>&nbsp;</o:p></SPAN></P>
                              <P class=MsoNormal 
                              style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0"><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">·位时钟恢复：位时钟恢复电路采用</SPAN><SPAN 
                              lang=EN-US>4</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">倍过采样原理，从输入的</SPAN><SPAN 
                              lang=EN-US>USB</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">数据流中恢复</SPAN><SPAN 
                              lang=EN-US><SPAN style="mso-spacerun: yes">&nbsp; 
                              </SPAN></SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">时钟。它能跟踪。</SPAN><SPAN 
                              lang=EN-US>USB</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">规定范围内的抖动和频漂。</SPAN></P>
                              <P class=MsoNormal 
                              style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0"><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">·</SPAN><SPAN 
                              lang=EN-US>PHILIPS</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">串行接口引擎</SPAN><SPAN 
                              lang=EN-US>(PSIE)</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">：</SPAN><SPAN 
                              lang=EN-US>PHILIPS SIE</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">实现了全部的</SPAN><SPAN 
                              lang=EN-US>USB</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">协议层。完全由</SPAN><SPAN 
                              lang=EN-US><SPAN style="mso-spacerun: yes">&nbsp; 
                              </SPAN></SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">硬件实现而不需要固件的参与。该模块的功能包括：同步模式的识别、并行／串行</SPAN><SPAN 
                              lang=EN-US><SPAN style="mso-spacerun: yes">&nbsp; 
                              </SPAN></SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">转换、位填充／解除填充、</SPAN><SPAN 
                              lang=EN-US>CRC</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">校验／产生、</SPAN><SPAN 
                              lang=EN-US>PID</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">校验／产生、地址识别和握手评估／产生。</SPAN></P>
                              <P class=MsoNormal 
                              style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0"><SPAN 
                              lang=EN-US><o:p>&nbsp;</o:p></SPAN></P>
                              <P class=MsoNormal 
                              style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0"><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">·</SPAN><SPAN 
                              lang=EN-US>SoftConnect</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">：高速设备与</SPAN><SPAN 
                              lang=EN-US>USB</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的连接是通过</SPAN><SPAN 
                              lang=EN-US>1</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">．</SPAN><SPAN 
                              lang=EN-US>5k</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">Ω上拉电阻将</SPAN><SPAN 
                              lang=EN-US>D+</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">职位高实现的。</SPAN><SPAN 
                              lang=EN-US><SPAN style="mso-spacerun: yes">&nbsp; 
                              </SPAN>1</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">．</SPAN><SPAN 
                              lang=EN-US>5k</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">Ω上拉电阻集成在</SPAN><SPAN 
                              lang=EN-US>PDIUSBDl2</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">片内，默认状态下不与</SPAN><SPAN 
                              lang=EN-US>VCC</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">相连。连接的建立</SPAN><SPAN 
                              lang=EN-US><SPAN style="mso-spacerun: yes">&nbsp; 
                              </SPAN></SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">通过外部系统微处理器发送命令来实现的。这就允许</SPAN><SPAN 
                              lang=EN-US>CPU</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在决定与’</SPAN><SPAN 
                              lang=EN-US>USB</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">建立连接之前完成初始化时序。</SPAN><SPAN 
                              lang=EN-US>USB</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">总线连接可以重新初始化而不需要拔出电缆。</SPAN></P>
                              <P class=MsoNormal 
                              style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0"><SPAN 
                              lang=EN-US><o:p>&nbsp;</o:p></SPAN></P>
                              <P class=MsoNormal 
                              style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0"><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">·</SPAN><SPAN 
                              lang=EN-US>GoodLink</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">：</SPAN><SPAN 
                              lang=EN-US>GoodLink</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">技术可提供良好的</SPAN><SPAN 
                              lang=EN-US>USB</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">连接指示。在枚举中，</SPAN><SPAN 
                              lang=EN-US>LED</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">指示灯根据通信的状况间歇闪烁。当</SPAN><SPAN 
                              lang=EN-US>PDIUSBDl2</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">成功的枚举和配置后，</SPAN><SPAN 
                              lang=EN-US>LED</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">指示灯将一直</SPAN><SPAN 
                              lang=EN-US><SPAN style="mso-spacerun: yes">&nbsp; 
                              </SPAN></SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">点亮。在</SPAN><SPAN 
                              lang=EN-US>PDIUSBD 12</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的数据传输过程中，</SPAN><SPAN 
                              lang=EN-US>LED</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">将闪烁；在挂起期间，</SPAN><SPAN 
                              lang=EN-US>LED</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">熄灭。</SPAN><SPAN 
                              lang=EN-US><SPAN style="mso-spacerun: yes">&nbsp; 
                              </SPAN></SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">这种特性为</SPAN><SPAN 
                              lang=EN-US>USB</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">器件、集线器和</SPAN><SPAN 
                              lang=EN-US>USB</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">通信状态提供了用户友好的指示。作为一个诊断工具，它对隔离故障的设备是很有用的。该特性降低了现场支持和热线的成本。</SPAN></P>
                              <P class=MsoNormal 
                              style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0"><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">·并行和</SPAN><SPAN 
                              lang=EN-US>DMA</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">接口：对一个微控制器而言，</SPAN><SPAN 
                              lang=EN-US>PDIUSBDl2</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">看起来就像一个带</SPAN><SPAN 
                              lang=EN-US>8</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">位数据总线和一个地址位</SPAN><SPAN 
                              lang=EN-US>(</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">占用</SPAN><SPAN 
                              lang=EN-US>2</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">个位置</SPAN><SPAN 
                              lang=EN-US>)</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的存储器件。</SPAN><SPAN 
                              lang=EN-US>PDIUSBDl2</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">支持独立的和分时复用的地址和数据总线。还支持主端点与本地共享</SPAN><SPAN 
                              lang=EN-US>RAM</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">之间直接读取的</SPAN><SPAN 
                              lang=EN-US>DMA</SPAN><SPAN 
                              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">传输，支持单周期和突发模式的</SPAN><SPAN