USB is not recognized occasionally

usb 1-2:new high-speed USB device number 12 using tegra-xusb
usb 1-2:device descriptor read/64,error -71
usb 1-2:device descriptor read/64,error -71
usb 1-2:new high-speed USB device number 13 using tegra-xusb
usb 1-2:device descriptor read/64,error -71
usb 1-2:device descriptor read/64,error -71
usb usb1-port2:unable to enumerate USB device

Honestly, you should tell more about your board design, software release. But not just posted a log without saying any other detail.

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At present, the DC Power Cycle test is carried out, and the setting is 500 times, and the USB is not recognized occasionally for 11 times.

Sorry, I didn’t describe the problem clearly. We currently use the NANO core board and self-developed carrier board. The NANO design refers to Jetson_Nano_Product_Design_Guide_DG-09502-001_v2.2. USB HUB chip selects VL817-Q7, and there is a problem that USB does not recognize occasionally. We use mirroring as the TUWEI for mirroring.

Hi, what the timing between 5V stable and POWER_EN on your board? Did you add the backup battery or super capacitor to BBAT?

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hi 5V stable RiseTime 1.36ms Power_EN Rise Time 1.32ms。Power_EN Pin is timed by a 10k resistor and 10nF capacitor. One end of the 10k resistor is connected to 5V, the other end is connected to the 10nF capacitor to the Power_EN pin, and the other end of the 10nF capacitor is grounded. BBAT pin is connected to 3V3.

Hi, I mean the delay time between 5V and POWER_EN not the rising time. Can you try more delay with like 100k resistor?

Can you add a super cap or backup battery to BBAT as the 3V3 is ON after power on?

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Glad to receive your reply。5V and POWER_EN delay time is 100us。After adjusting the delay time to 1ms, the system cannot be entered。Adjust the delay time to 1us, and the system is normal。 We can provide our design drawings, and you need to review them to find out the cause of the problem。I can send you an email, I need to know your email address。What we are not sure about is whether the selection of our HUB controller is appropriate, or what problem caused the occasional failure of USB recognition。At present, occasional failure of USB recognition is random。USB2.0 will also be unrecognized and the HUB will be unavailable。

Please check your power rails on carrier board. The key point is to let all rails on carrier are stable and then assert POWER_EN. We don’t support schematic review for JEP customer in general as we have provided the OEM design guide and devkit schematic for reference. Customer is expected to follow that well and check custom design based on that.

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Hi I am sorry to reply you so late,We are currently adding super capacitors to BBAT. We test DC Power Cycel 100 times, and the USB does not recognize occasionally . We will adjust the test cycle to 300 times. We will continue to follow up on this test. We will confirm whether this phenomenon has been resolved tomorrow. After adding the super capacitor, there is a drawback. The startup interval will be extended from the original 10 seconds to 90 seconds. After 90 seconds, the system can be re-entered, otherwise the system will not start. The development board reference design I I didn’t find it. I only have a Product Design Guide . Can you provide me with a link? thanks.

After we added 80mF of super capacitor to the BBAT pin, DC Power Cycle 300 times, the USB does not exist occasionally . This problem is solved, but two new problems are introduced. Problem 1: The USB2.0 keyboard cannot be used, but it can be recognized. Question 2: The network port occasionally fails to ping the core board IP 192.168.3.112.DC Power cycle 300 times,The network port fails is 21 times。

Please try more delay between 5V and POWER_EN, it can be 200+ ms if necessary. You can compare to devkit for the delay.