【LSM6DSOX有限状态机例程学习 三】--垂直翻转（Flip Down）
<p><span style="font-size:14.0pt"><span lang="zh-CN" style="font-family:"Microsoft YaHei"">上周末，</span><a href="https://bbs.eeworld.com.cn/thread-1137203-1-1.html"><span lang="zh-CN" style="font-family:"Microsoft YaHei"">有限状态机及例程简介</span></a><span lang="zh-CN" style="font-family:"Microsoft YaHei"">和</span><a href="https://bbs.eeworld.com.cn/thread-1137248-1-1.html"><span lang="zh-CN" style="font-family:"Microsoft YaHei"">有限状态机编程使用方法</span></a><span lang="zh-CN" style="font-family:"Microsoft YaHei"">这两篇帖子已经较为详细的介绍了</span><span lang="en-US" style="font-family:"Times New Roman"">L</span><span lang="zh-CN" style="font-family:"Times New Roman"">SM6DSOX</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">的有限状态机的特点和基本的使用方法。本周开始，我将对</span><span lang="en-US" style="font-family:"Microsoft YaHei"">ST</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">官方所提供的</span><span lang="en-US" style="font-family:"Microsoft YaHei"">FSM</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">例程进行讲解分享，从例程理解到复现，进一步掌握</span><span lang="en-US" style="font-family:"Times New Roman"">L</span><span lang="zh-CN" style="font-family:"Times New Roman"">SM6DSOX</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">有限状态机的使用方法。</span></span></p><p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""> </span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">小伙伴们可以先去github上下载下ST的<a href="https://github.com/STMicroelectronics/STMems_Finite_State_Machine">MEMS有限状态机的例程仓库</a>，为方便起见，我已经将LSM6DSOX的例程打包上传到百度云了，链接和提取码如下：</span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""><a href="https://pan.baidu.com/s/1PAexCkAoEr5qmKMo5xYMOg">https://pan.baidu.com/s/1PAexCkAoEr5qmKMo5xYMOg</a></span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">提取码：ufln</span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""> </span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">下载并解压后，可以得到如下七个文件夹：</span></span></p>
<p></p>
<p><span style="font-size:14.0pt"><span lang="zh-CN" style="font-family:"Microsoft YaHei"">每个文件中包含了</span><span lang="en-US" style="font-family:"Times New Roman"">README.</span><span lang="en-US" style="font-family:"Microsoft YaHei"">md</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">、后缀</span><span lang="en-US" style="font-family:"Microsoft YaHei"">.h</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">、后缀</span><span lang="en-US" style="font-family:"Microsoft YaHei"">.ucf</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">文件，其中：</span></span></p>
<p><span style="font-size:14.0pt"><span lang="en-US" style="font-family:"Times New Roman"">README.</span><span lang="en-US" style="font-family:"Microsoft YaHei"">md </span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">简单的介绍了示例的基本信息</span></span></p>
<p><span style="font-size:14.0pt"><span lang="zh-CN" style="font-family:"Microsoft YaHei"">后缀</span><span lang="en-US" style="font-family:"Times New Roman"">.</span><span lang="en-US" style="font-family:"Microsoft YaHei"">h</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">文件是根据</span><span lang="en-US" style="font-family:"Microsoft YaHei"">FSM</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">的具体配置参数，通过</span><span lang="en-US" style="font-family:"Microsoft YaHei"">Unico GUI</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">生成的</span><span lang="en-US" style="font-family:"Microsoft YaHei"">C</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">代码头文件，可以很方便的将其独立的运行在自己的工程程序中。</span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">后缀.ucf文件是Unico GUI的标准配置文件，Unico GUI可以直接将配置信息保存为ucf文件，也可以将其加载并导入到传感器中。</span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""> </span></span></p>
<p><span style="font-size:14.0pt"><span lang="zh-CN" style="font-family:"Microsoft YaHei"">本帖主要来讲解下</span> <span lang="zh-CN" style="font-family:"Microsoft YaHei"">翻转识别</span><span lang="en-US" style="font-family:"Times New Roman"">F</span><span lang="zh-CN" style="font-family:"Times New Roman"">lip-Down detection</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">示例的实现过程。</span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""> </span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">LSM6DSOX这款传感器定位在物联网、低功耗角度，那么一定是考虑各种物联网设备的应用角度来设计的。 </span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""> </span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">例程中的翻转识别，顾名思义就是识别设备是否被翻转到一定的角度，这个应用在智能手表、手机上可以经常简单到，比如有的手机可以设置翻扣手机设置静音、智能手表抬腕显示时间等等。</span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""> </span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">那么翻转识别是怎么是实现的呢？</span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""> </span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">在地球上任意地方，都会存在一个指向地心的重力加速度，而传感器中的加速度计就可以感应到这个加速度存在，加速度计有三个方向的感知能力，分别是X\Y\Z，重力加速度在这三个轴方向上的矢量和便指向了地心，那么通过重力加速度就可以判断出传感器的方向。</span></span></p>
<p></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Times New Roman""> </span></span></p>
<p><span style="font-size:14.0pt"><span lang="zh-CN" style="font-family:"Microsoft YaHei"">明白了该如何实现此功能之后，我们来看下官方给的</span><span lang="en-US" style="font-family:"Times New Roman"">F</span><span lang="zh-CN" style="font-family:"Times New Roman"">lip-Down detection</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">例程，通过</span><span lang="en-US" style="font-family:"Microsoft YaHei"">Unico GUI</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">的</span><span lang="en-US" style="font-family:"Microsoft YaHei"">load</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">功能，将</span><span lang="en-US" style="font-family:"Microsoft YaHei"">ucf</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">文件配置到传感器上</span></span></p>
<p></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Times New Roman""> </span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">当load按钮左边显示Loaded的时候，参数就加载好了。</span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">此时，打开左边的FSM控件，我们就可以看到<span lang="zh-CN" style="font-weight:bold">翻转识别</span>的状态机代码了。</span></span></p>
<p></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Times New Roman""> </span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">关于这个编程界面的讲解，可以参考上一篇文章：<a href="https://bbs.eeworld.com.cn/thread-1137248-1-1.html">有限状态机编程使用方法</a></span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""> </span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">我们来看下这个这段例程，一共7条语句，结合上篇文章中的末尾的指令集说明文档，</span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">逐句的分析下每句的意义：</span></span></p>
<p lang="en-US"><span style="font-size:14.0pt"><span style="font-weight:bold"><span style="font-family:"Times New Roman"">S0: </span></span><span style="font-weight:bold"><span style="font-family:"Microsoft YaHei"">RNC NOP GNTH2</span></span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">一条判断语句，GNTH2：当某轴数据大于Thresh2则成立，NOP：否则就重置。</span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">可以看到左边变量区中Thresh2 = 0，Mask A = 08 ，那么根据掩码的设置规则：</span></span></p>
<p></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">这里选择的就是Z轴正方向，那么这条语句的意义就是 当Z轴正向加速度数值大于0的时候就成立，可以跳转到S1条，否则则返回S0.</span></span></p>
<p lang="en-US"><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""><span style="font-weight:bold">S1: RNC LNTH2 TI4</span></span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">又是一条判断语句，这里的前进条件是TI4：当定时计数大于Timer4设置的阈值则成立，重置条件是LNTH2：当某轴的数据小于Thresh2。这里的定时计数器时间基准是根据FSM OCR设置的频率来计数的,Timer = 0x0D,则总时长为1/26*13 = 0.5s。那么这条语句的意思就是如果Z轴正方向加速度值大于0g超过0.5s则跳转到S2,否则跳转到S0.</span></span></p>
<p lang="en-US"><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""><span style="font-weight:bold">S2: SRP</span></span></span></p>
<p><span style="font-size:14.0pt"><span lang="zh-CN" style="font-family:"Microsoft YaHei"">这是一条命令指令，意义是将复位重置指针设置为下一个地址，也就是之后再遇到判断语句的重置状态则跳转到</span><span lang="en-US" style="font-family:"Times New Roman"">S3,</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">而不跳转到</span><span lang="en-US" style="font-family:"Microsoft YaHei"">S0.</span></span></p>
<p lang="en-US"><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""><span style="font-weight:bold">S3: GNTH1 TI3</span></span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">这条判断语句的前进条件为TI3:也就是当定时计数大于Timer3设置的阈值则成立，重置条件是GNTH1:当某轴的数据大于Thresh1，则重置。Thresh1 = -0.85，Z轴正方向加速度值大于-0.85，那也就是Z轴正向加速度小于-0.85g超过1/26*10=0.38s以上，则跳转到S4,否则跳转S3。</span></span></p>
<p lang="en-US"><span style="font-size:14.0pt"><span style="font-family:"Times New Roman""><span style="font-weight:bold">S4:CRP</span></span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">这条命令指令重置SRP的作用，将复位重置指针设置回S0,</span></span></p>
<p lang="en-US"><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""><span style="font-weight:bold">S5:CONTREL</span></span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">这条指令执行循环到重置点S0，并且将掩码输出到OUTSx寄存器中，同时，由于SM1 Status中设置了INT1，也就是将中断路由到了外部输出中断引脚上，那么在执行S5指令时，则可以看到外部中断输出INT1产生脉冲。</span></span></p>
<p lang="en-US"><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""><span style="font-weight:bold">S6:STOP</span></span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">这条指令时停止执行指令，从上数代码来看一般不会跳转到这个位置。</span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""> </span></span></p>
<p><span style="font-size:14.0pt"><span lang="en-US" style="font-family:"Times New Roman"">ST</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">官方为了方便编程，还做了状态机图显示界面，打开</span><span lang="en-US" style="font-family:"Microsoft YaHei"">Debug</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">标题栏，就可以看到如下：</span></span></p>
<p></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""> </span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">那么结合上述指令简介和状态机图，我们不难分析出他的具体工作流程是：</span></span></p>
<p><span style="font-size:14.0pt"><span lang="en-US" style="font-family:"Times New Roman"">1</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">、首先，传感器正向为</span><span lang="en-US" style="font-family:"Microsoft YaHei"">Z</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">轴正向方向，那么在一般的时候，他应该是朝着向上的方向，</span><span lang="en-US" style="font-family:"Microsoft YaHei"">S0</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">和</span><span lang="en-US" style="font-family:"Microsoft YaHei"">S1 </span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">才回成立，也就避免了设备处于面板朝下的状态，再变到反向正朝下的时候产生中断的问题。</span></span></p>
<p><span style="font-size:14.0pt"><span lang="en-US" style="font-family:"Times New Roman"">2</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">、当排除了</span><span lang="en-US" style="font-family:"Microsoft YaHei"">1</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">的问题后，只要判断设备是否正向超下了一定时间，就可以得到翻转识别的效果了。</span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei""> </span></span></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">下面是测试效果的视频：</span></span></p>
<p><iframe allowfullscreen="true" frameborder="0" height="510" src="https://training.eeworld.com.cn/shareOpenCourseAPI?isauto=true&lessonid=27141" style="background:#eee;margin-bottom:10px;" width="750"></iframe></p>
<p><span style="font-size:14.0pt"><span style="font-family:"Microsoft YaHei"">思考题：</span></span></p>
<p><span style="font-size:14.0pt"><span lang="en-US" style="font-family:"Times New Roman"">1</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">、假如设备安装传感器的方向不是</span><span lang="en-US" style="font-family:"Microsoft YaHei"">Z</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">轴正向朝向面板方向，而是</span><span lang="en-US" style="font-family:"Microsoft YaHei"">X</span><span lang="zh-CN" style="font-family:"Microsoft YaHei"">轴正向的话，那么我们想要实现识别翻扣设备的动作该怎么修改配置呢？</span></span></p>
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