USB leds not illuminating
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Hi,
I have setup the V2 LTE module with a rpi4. I connected the module to the pi through the upstream usb port on the module. I am powering the entire module with 5v DC power through the back connector, but i'm only seeing the three LEDs by the upstrem usb illuminate. The other LEDs (by the downstream ports illuminate occasionally). I'm guessing the module is not getting enough power? Are the usb ports powered separately from the rest of the board? -
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I am assuming you have a standalone board, and when you say the "back connector" you are referring to the 2-pin Red JST connector J3, and you might be using our MCBL-00017 to provide 5V, correct?
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Yes, The three LEDs together near the 4-pin J4 indicate 5V is present, a local 3.8V is good, and the Modem is powered up.
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You are using the J4 4-pin JST to connect to the RPI4 host, correct?
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The other two LEDs near J6/J5 downstream ports will only illuminate when the USB hub is enumerated with a host. The source of the USB VBUS on the two downstream ports J5 and J6 come from the J3 red power connector, not the J4 Host VBUS power. However, the host VBUS is used as a "detect" for enumeration. So, it must still be present and valid on J4 from the Rpi4 for the USB hub to enumerate.
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If you suspect your 5V DC supply through J3 is not sufficient, start by removing the Modem and see if you can maintain USB functionality that way. Then, once you plug back in the Modem to the socket, if you start having issues again, it could be a sign your source 5V is not sufficient to power the module. We have a few data points of power consumption on our website to help you gauge how much power you might need:
https://docs.modalai.com/lte-modem-and-usb-add-on-v2-datasheet/#power-consumption -
Another thing is to try for intermittent cables. If the host connection is loose, you will loose enumeration with the host and see those 2 downstream LEDs go out.
Let us know if you can get this working.
BTW, I am not in SW, but whatever you can do on the Rpi4 module to check if the USB hub is alive through the Rpi4 terminal/console (the equivalent of LS-USB or something like that on our Voxl platforms) during this would be useful as well. That way you can know if you maintain host connection or not during these events, helping to further troubleshoot your root cause.
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@Henry-Cappel have you used the enable script here?
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Thanks @Vinny and @Chad-Sweet for responding! I'll try to give you guys some more information so hopefully this makes more sense.
I used the enable script and ran all the commands on ubuntu 20.04 on the pi. I was able to establish a connection momentarily by seeing the device come up with lsusb. I had connection to the internet for a little while, but then the connection became very spotty (the two downstream LEDs would go on and off) and eventually to the point where the device would not even show up at all with lsusb.
I'm realizing now from your reply @Vinny that this issue is much more likely to be with the enumeration of the pi with the module as I didn't realize that the LEDs were indicators of connection as opposed to power supply.
To answer your questions in order @Vinny :
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Yes, I am using the standalone board and I am referring to the 2-pin J3 connector on the back currently powered by the Rpi 5v pinout (I have also tried using a different 5V power source outside of the Pi)
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Yes, I am using the J4 4-pin to connect to the Rpi
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It very well could be a bad USB cable, so I will try to create a new one and see if that helps, but I have already tried with two different cables and had the same problem, so I'm not sure
Let me know if this brings up anything yall can think of. But thanks a ton for the help!
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One more thing came to mind. I realize that I can only get any sort of connection between the pi and module if I power the module via the 5V pin on the pi. The only thing I can think of is that the usb connector and the 5V DCin share a common ground which may create a better connection?
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@Henry-Cappel said in USB leds not illuminating:
The only thing I can think of is that the usb connector and the 5V DCin share a common ground which may create a better connection?
Yes, our GNDs are all common between VBUS and the 5V_DCIN.
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@Henry-Cappel said in [ @Vinny that this issue is much more likely to be with the enumeration of the pi with the module as I didn't realize that the LEDs were indicators of connection as opposed to power supply ]
To clarify, it's a representation of enumeration... Once enumerated with a host, the hub enables the downstream ports, and hence the LEDs illuminate. So one can imply enumeration and VBUS port power are both OK when those LEDs are on.
Hope that clarifies things. -
@Vinny Thanks that does! So I made a new wire and it worked! It turns out my issue was that because I created a custom USB 2.0 to 4 pin JST connector I had too much exposed wiring. USB apparently requires a ton of shielding around all the wires to work which I did not know until now. Thanks for all the help with clarification
