常见泽1 发表于 2020-10-9 16:56

【AT-START-F403A测评】第2篇 F403波形输出测试及最大频率测试

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">时钟波形输出测试</span></span></span></p>

<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">和</span>STM32<span style="font-family:宋体">一样，具有</span>MCO<span style="font-family:宋体">功能</span>STM32<span style="font-family:宋体">的</span>PA.8<span style="font-family:宋体">引脚具有复用功能&mdash;&mdash;时钟输出</span>(MCO)<span style="font-family:宋体">，</span> <span style="font-family:宋体">该功能能将</span>STM32<span style="font-family:宋体">内部的时钟通过</span>PA.8<span style="font-family:宋体">输出</span>.</span></span></p>

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">AT<span style="font-family:宋体">可供</span>MCO<span style="font-family:宋体">输出的波形如下：</span></span></span></p>

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">执行代码：</span></span></span></p>

<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">void MCO_config(void)</span></span></p>

<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">{</span></span></p>

<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">&nbsp; GPIO_InitType GPIO_InitStructure;</span></span></p>

<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">&nbsp; </span></span></p>

<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">&nbsp; RCC_APB2PeriphClockCmd(RCC_APB2PERIPH_GPIOA,ENABLE); </span></span></p>

<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">&nbsp; GPIO_StructInit(&amp;GPIO_InitStructure);</span></span></p>

<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">&nbsp; GPIO_InitStructure.GPIO_Pins = GPIO_Pins_8; </span></span></p>

<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">&nbsp; GPIO_InitStructure.GPIO_MaxSpeed = GPIO_MaxSpeed_50MHz;</span></span></p>

<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">&nbsp; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></p>

<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">&nbsp; GPIO_Init(GPIOA, &amp;GPIO_InitStructure);</span></span></p>

<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">&nbsp;</span></span></p>

<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">&nbsp; RCC_CLKOUTConfig(RCC_CLKOUT_SYSCLK, RCC_MCOPRE_1);</span></span></p>

<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">}</span></span></p>

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">通过更改参数来更改输出波形</span></span></span></p>

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">1.<span style="font-family:宋体">系统时钟输出</span></span></span></p>

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">配置系统时钟</span>30<span style="font-family:宋体">倍频，输出位</span>30*8=240MHz</span></span></p>

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">手册里标注最大</span>240MHZ<span style="font-family:宋体">，我们来测试下最大能跑多少</span>MHZ</span></span></p>

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">改成</span>34<span style="font-family:宋体">倍频</span> =34*8=272MHZ</span></span></p>

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">改成</span>35<span style="font-family:宋体">倍频</span> 35*8=280MHZ</span></span></p>

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">改成</span>36<span style="font-family:宋体">倍频</span> =288MHZ</span></span></p>

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">改成</span>37<span style="font-family:宋体">倍频</span> = 296MHZ <span style="font-family:宋体">发现波形频率不对了</span></span></span></p>

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">2.HIS<span style="font-family:宋体">时钟输出</span></span></span></p>

<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">内部时钟</span>8MHZ<span style="font-family:宋体">波形输出</span></span></span></p>

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">其实</span>AT<span style="font-family:宋体">内部是</span>48M HIS RC</span></span></p>

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">3.LSI<span style="font-family:宋体">时钟输出</span></span></span></p>

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">看手册里</span></span></span></p>

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">典型值是</span>40KHZ<span style="font-family:宋体">，</span>ST<span style="font-family:宋体">的类似的我测试过，大概都是</span>40KHZ<span style="font-family:宋体">左右，偏差不是很大，</span>AT<span style="font-family:宋体">的</span>LSI<span style="font-family:宋体">偏差还是有点大的，采用内部时钟</span>RTC<span style="font-family:宋体">应该不会很准</span></span></span></p>

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<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif">4.PLL<span style="font-family:宋体">时钟输出</span>&nbsp; PLL/4<span style="font-family:宋体">分频</span></span></span></p>

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freebsder 发表于 2020-10-11 21:35

<p>内部晶振一般也不用,本来就不太准,个体差异也有点大</p>

RCSN 发表于 2020-10-12 22:00

<p>泽哥牛逼</p>

okhxyyo 发表于 2020-10-19 10:08

<p><a href="https://bbs.eeworld.com.cn/thread-1143018-1-1.html" target="_blank">雅特力AT-START-F403A测评汇总</a></p>

<p>汇总贴：<a href="https://bbs.eeworld.com.cn/thread-1143018-1-1.html" target="_blank">https://bbs.eeworld.com.cn/thread-1143018-1-1.html</a></p>
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