https://community.nxp.com/t5/i-MX-Processors/IMX8MP%E7%9A%84USBn-VBUS%E5%AE%9E%E9%99%85%E5%8A%9F%E8%83%BD%E5%92%8C%E5%A6%82%E4%BD%95%E4%BD%BF%E7%94%A8%E9%97%AE%E9%A2%98/m-p/2329514#M244412 <P>如题，我现在接手的设计是USB1_VBUS通过5V分压3.3使能，USB1引出3.0的Type-c接口使用；<BR />USB2_VBUS直接悬空，USB2连接3.0HUB使用；<BR />我发现USB2_VBUS悬空也可以正常通过HUB连接U盘使用，此信号貌似不是必须上拉的；<BR />我的疑问：1.此信号的实际作用是什么？与HOST/DEVICE有关么？<BR />&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 2.如果我将USB1改为直连HUB不使用其OTG功能是否也可以将USB1_VBUS悬空？</P> Tue, 10 Mar 2026 08:45:40 GMT 昙天 2026-03-10T08:45:40Z https://community.nxp.com/t5/i-MX-Processors/IMX8MP%E7%9A%84USBn-VBUS%E5%AE%9E%E9%99%85%E5%8A%9F%E8%83%BD%E5%92%8C%E5%A6%82%E4%BD%95%E4%BD%BF%E7%94%A8%E9%97%AE%E9%A2%98/m-p/2329514#M244412 <P>如题，我现在接手的设计是USB1_VBUS通过5V分压3.3使能，USB1引出3.0的Type-c接口使用；<BR />USB2_VBUS直接悬空，USB2连接3.0HUB使用；<BR />我发现USB2_VBUS悬空也可以正常通过HUB连接U盘使用，此信号貌似不是必须上拉的；<BR />我的疑问：1.此信号的实际作用是什么？与HOST/DEVICE有关么？<BR />&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 2.如果我将USB1改为直连HUB不使用其OTG功能是否也可以将USB1_VBUS悬空？</P> Tue, 10 Mar 2026 08:45:40 GMT https://community.nxp.com/t5/i-MX-Processors/IMX8MP%E7%9A%84USBn-VBUS%E5%AE%9E%E9%99%85%E5%8A%9F%E8%83%BD%E5%92%8C%E5%A6%82%E4%BD%95%E4%BD%BF%E7%94%A8%E9%97%AE%E9%A2%98/m-p/2329514#M244412 昙天 2026-03-10T08:45:40Z https://community.nxp.com/t5/i-MX-Processors/IMX8MP%E7%9A%84USBn-VBUS%E5%AE%9E%E9%99%85%E5%8A%9F%E8%83%BD%E5%92%8C%E5%A6%82%E4%BD%95%E4%BD%BF%E7%94%A8%E9%97%AE%E9%A2%98/m-p/2331280#M244454 <DIV id="tinyMceEditor_10e072dbbd0a72Rita_Wang_0" class="mceNonEditable lia-copypaste-placeholder">&nbsp;</DIV> <P>1）这个pin是<SPAN data-slate-fragment="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">就是3.3V的电源轨的检测PIN。USBx_VBUS 是 USB 的输入信号，用于检测外部 5V VBUS 是否存在，控制 USB PHY 的启动与 Host/Device 选择。</SPAN></P> <P><SPAN data-slate-fragment="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">Device/otg模式下必须接，经过30K接到5V，或者是经过1k接到3.3V上。若没有 VBUS 输入，控制器无法进入 Device 模式。</SPAN></P> <P><SPAN data-slate-fragment="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">Host下可以不接，你可以看到我们的参考设计中</SPAN></P> <P>&nbsp;</P> <DIV id="tinyMceEditorRita_Wang_0" class="mceNonEditable lia-copypaste-placeholder">&nbsp;</DIV> <DIV id="tinyMceEditorRita_Wang_1" class="mceNonEditable lia-copypaste-placeholder">&nbsp;</DIV> <P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="image - 2026-03-12T172729.422.png" style="width: 568px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/379066i5115B3088C1322FE/image-size/large?v=v2&amp;px=999" role="button" title="image - 2026-03-12T172729.422.png" alt="image - 2026-03-12T172729.422.png" /></span></P> <P>2）可以的，但是不建议USB1做HUB, usb1要用来做下载，设计时候保持功能，debug板子的时候比较方便，参考我们的参考设计哈</P> Thu, 12 Mar 2026 09:38:05 GMT https://community.nxp.com/t5/i-MX-Processors/IMX8MP%E7%9A%84USBn-VBUS%E5%AE%9E%E9%99%85%E5%8A%9F%E8%83%BD%E5%92%8C%E5%A6%82%E4%BD%95%E4%BD%BF%E7%94%A8%E9%97%AE%E9%A2%98/m-p/2331280#M244454 Rita_Wang 2026-03-12T09:38:05Z https://community.nxp.com/t5/i-MX-Processors/IMX8MP%E7%9A%84USBn-VBUS%E5%AE%9E%E9%99%85%E5%8A%9F%E8%83%BD%E5%92%8C%E5%A6%82%E4%BD%95%E4%BD%BF%E7%94%A8%E9%97%AE%E9%A2%98/m-p/2333825#M244521 好的，非常感谢 Tue, 17 Mar 2026 06:11:32 GMT https://community.nxp.com/t5/i-MX-Processors/IMX8MP%E7%9A%84USBn-VBUS%E5%AE%9E%E9%99%85%E5%8A%9F%E8%83%BD%E5%92%8C%E5%A6%82%E4%BD%95%E4%BD%BF%E7%94%A8%E9%97%AE%E9%A2%98/m-p/2333825#M244521 昙天 2026-03-17T06:11:32Z