Custom carrier board can not boot when HDMI connectted to monitor


I am designing a custom carrier board for Jetson Nano Module.

When the HDMI port is not connected to the device, it can boot normally.

However, after the HDMI interface is connected to the monitor, it cannot be turned on normally. Oscilloscope shows that when power on SHUTDOWN_ REQ*(FORCE_ Off *) pin will have low pulse, resulting in Power_EN pin becomes low after a high pulse.

What conditions will enable SHUTDOWN_ REQ* when power on。


Please share the boot up log from uart.

You may need to read this post before dumping the log. Or you’ll have to do it several times before dumping the correct log.

Hi WayneWWW,

Thanks for your reply!

When power on, Power_EN pin becomes low after a high pulse. So cpu can not run and no boot up log from uart.

It might be caused by bad VDD_IN, please probe VDD_IN. Also compare your HDMI design to reference to find out root cause.

Hi Trumany,
Thanks for your reply!
The waveform of VDD_IN shows:

And also the reset function can not work. When pull down the RESET pin, the board can be turned off, but can not be turn on, although the POWER_EN pin remains high.

Is there a reset sequence?

VDD_IN looks fine. What’s the difference on HDMI design between yours and reference? Since it is cause by your HDMI design, you should check and compare that to dev kit.

The real reason is the UART port voltage error. Now whether HDMI is connected or not, the startup and reset functions can be used normally.