https://community.nxp.com/t5/i-MX-Processors/i-MX8QM-USB-boot-Fail/m-p/1880077#M224497 <P>Hello,</P> <P>Could you please share the power, boot mode switches and USB sections? To discard any issue on hardware side.</P> <P>Best regards.</P> Mon, 03 Jun 2024 21:21:27 GMT JorgeCas 2024-06-03T21:21:27Z https://community.nxp.com/t5/i-MX-Processors/i-MX8QM-USB-boot-Fail/m-p/1878525#M224390 <P>你好，</P><P>&nbsp;</P><P>我用i.MX8QM制作了一个板子，默认boot模式为eMMC0 boot，可手动切换为USB Serial Download模式。</P><P>我出现的问题是：</P><P>在默认boot模式下，板子上电正常。外部稳压源给板子的供电电压为5V，实际输出电流为0.65A。在手动切换到USB Serial Download模式后，稳压源电压输出保持不变，但输出电流降低到0.44A。经测PMIC1和PMIC2的SW regulator输出电压，发现异常。比如：SW7应该输出3.3V，实测为3.0V。SW6应该输出1.1V，实测为0.8V。将boot模式切换为默认模式后，稳压源输出电流又恢复至0.65A，PMIC的输出电压又恢复正常。</P><P>因为切换到USB Serial Download模式后，PMIC输出电压异常，导致上位机无法识别i.MX8这个USB设备。</P><P>感谢你的关注，期待你的解答与帮助，谢谢！</P> Fri, 31 May 2024 02:23:54 GMT https://community.nxp.com/t5/i-MX-Processors/i-MX8QM-USB-boot-Fail/m-p/1878525#M224390 st_hw 2024-05-31T02:23:54Z https://community.nxp.com/t5/i-MX-Processors/i-MX8QM-USB-boot-Fail/m-p/1880077#M224497 <P>Hello,</P> <P>Could you please share the power, boot mode switches and USB sections? To discard any issue on hardware side.</P> <P>Best regards.</P> Mon, 03 Jun 2024 21:21:27 GMT https://community.nxp.com/t5/i-MX-Processors/i-MX8QM-USB-boot-Fail/m-p/1880077#M224497 JorgeCas 2024-06-03T21:21:27Z