https://zeseanblog.top/tags/spi/Recent content in SPI on Zesean 的博客Hugo -- gohugo.iozh-CNTue, 01 Sep 2026 22:58:08 +0800https://zeseanblog.top/p/spi/Sat, 12 Apr 2025 09:30:00 +0800https://zeseanblog.top/p/spi/<h1 id="spi通信"><a href="#spi%e9%80%9a%e4%bf%a1" class="header-anchor"></a>SPI通信 </h1><ul> <li> <p>SPI：通用数据总线</p> </li> <li> <p>四根通信线：轻松Mhz</p> <ul> <li> <p>SCK(Serial Clock)</p> </li> <li> <p>MOSI(Master Output Slave Input)</p> </li> <li> <p>MISO(Master Input Slave Output)</p> </li> <li> <p>SS(Slave Select)</p> </li> </ul> </li> <li> <p>同步，全双工</p> </li> <li> <p>支持总线挂载多设备（一主多从）</p> </li> </ul> <p>常用模块：W25Q64 FLASH存储器、SPI OLED屏、NRF24L01 2.4G无线通讯模块、SD卡 支持SPI</p> <h2 id="硬件电路"><a href="#%e7%a1%ac%e4%bb%b6%e7%94%b5%e8%b7%af" class="header-anchor"></a>硬件电路 </h2><ul> <li>所有SPI设备SCK、MOSI、MISO分别连接在一起</li> <li>主机引出多条SS控制线，分别连接各从机SS引脚</li> <li>输出引脚配置推挽输出（驱动能力强，驱动上下降沿强），输入引脚配置浮空或上拉</li> </ul> <img src="images/image-20250925170440759.png" alt="image-20250925170440759" style="zoom:67%;" /> <p>主机指定从机：将对应SS线输出低电平，其余高电平</p> <h2 id="移位示意图"><a href="#%e7%a7%bb%e4%bd%8d%e7%a4%ba%e6%84%8f%e5%9b%be" class="header-anchor"></a>移位示意图 </h2><img src="images/image-20250925171058081.png" alt="image-20250925171058081" style="zoom:80%;" /> <p>波特率发生器作为时钟，每一个上升沿，移位寄存器移出一位，进行数据发送；每一个下降沿，最低位采样</p> <img src="images/image-20250925171304695.png" alt="image-20250925171304695" style="zoom:80%;" /> <p>一般主机发0x00或0xff跟从机交换数据</p> <h2 id="spi时序基本单元"><a href="#spi%e6%97%b6%e5%ba%8f%e5%9f%ba%e6%9c%ac%e5%8d%95%e5%85%83" class="header-anchor"></a>SPI时序基本单元 </h2><ul> <li>起始条件：SS高电平到低电平</li> <li>终止条件：SS低电平切换高电平</li> </ul> <p><img alt="image-20250925171622639" class="gallery-image" data-flex-basis="1494px" data-flex-grow="622" height="137" loading="lazy" sizes="(max-width: 767px) calc(100vw - 30px), (max-width: 1023px) 700px, (max-width: 1279px) 950px, 1232px" src="https://zeseanblog.top/p/spi/images/image-20250925171622639.png" srcset="https://zeseanblog.top/p/spi/images/image-20250925171622639_hu_bf9253fce5076353.png 800w, https://zeseanblog.top/p/spi/images/image-20250925171622639.png 853w" width="853"></p> <p>SPI由不同的移位模型，能根据SCK的不同边沿变化进行移位。</p> <h3 id="模式1"><a href="#%e6%a8%a1%e5%bc%8f1" class="header-anchor"></a>模式1 </h3><p>CPOL=0：空闲状态时，SCK低电平</p> <p>CPHA=1：SCK第一个边沿移出数据，第二个边沿移入数据（数据采样）</p> <p><img alt="image-20250925171826936" class="gallery-image" data-flex-basis="732px" data-flex-grow="305" height="326" loading="lazy" sizes="(max-width: 767px) calc(100vw - 30px), (max-width: 1023px) 700px, (max-width: 1279px) 950px, 1232px" src="https://zeseanblog.top/p/spi/images/image-20250925171826936.png" srcset="https://zeseanblog.top/p/spi/images/image-20250925171826936_hu_911829cf886d67fc.png 800w, https://zeseanblog.top/p/spi/images/image-20250925171826936.png 995w" width="995"></p> <h3 id="模式0"><a href="#%e6%a8%a1%e5%bc%8f0" class="header-anchor"></a>模式0 </h3><p>CPOL=0:空闲状态时，SCK为低电平 CPHA=0: SCK第一个边沿移入数据,第二个边沿移出数据</p> <p>将第一个数据变化的时机提前</p> <p><img alt="image-20250925172507991" class="gallery-image" data-flex-basis="720px" data-flex-grow="300" height="335" loading="lazy" sizes="(max-width: 767px) calc(100vw - 30px), (max-width: 1023px) 700px, (max-width: 1279px) 950px, 1232px" src="https://zeseanblog.top/p/spi/images/image-20250925172507991.png" srcset="https://zeseanblog.top/p/spi/images/image-20250925172507991_hu_3ab423fd4e852e0f.png 800w, https://zeseanblog.top/p/spi/images/image-20250925172507991.png 1006w" width="1006"></p> <h2 id="spi时序"><a href="#spi%e6%97%b6%e5%ba%8f" class="header-anchor"></a>SPI时序 </h2><p>W25Q64为例，芯片厂商规定</p> <ul> <li>发送指令</li> <li>向SS指定设备，发送指令（0x06），00000110</li> </ul> <img src="images/image-20250925173135029.png" alt="image-20250925173135029" style="zoom:67%;" />