[Solved / Archived] Zero4U

Posted by: @factoid9311

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Self-powered mode provides up to 2A to all USB ports, but does this include the host port?

With default configuration, the host port serves as a source of power, instead of a load.

There is a zero-ohm resistor (R8) between host port and the XH2.54 power connector. There is a 2A polyfuse between the XH2.54 connector and the Vusb of 4 downstream ports.

Posted by: @factoid9311

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PP22/PP23 are directly connected to the "Alt USB In"/USB-mini connector

That is correct.

Posted by: @factoid9311

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If the host is providing power in bus-powered mode and then 5V externally is plugged in

This is not recommended, because it may also back-feed your Raspberry Pi, unless you remove R8.

It is recommended to do some testings under real enviroment, to figure out if it fits your needs.

I'm using an Android tablet as the host, so my application is a bit different but I think it will work. Thanks for input @admin.

I'm having issues connecting the Zero4U hat to my v1.1 Pi Zero W's. The pins are aligned to the test pads and visually they appear to make good contact.

What I am seeing: the kernel seems to intermittently reset the connection to the device and increment the device ID for the hub as well as any device connected to the hub. It also appears that communications with the Zero4U hat are, at times, lost completely.

Here are the steps I have taken to troubleshoot, which have all resulted in the same undesired results:

1) Tested with and without the ferrite.

2) Test on different boards of the same version v1.1.

3) Tested with a fresh RPi OS image.

I think that my Zero4U board is possibly defective or maybe these Pi Zero W boards don't like the Zero4u.

Here is what I'm seeing, as the device ID continues to be incremented by the kernel over time:

root@rpizw-test:/root# lsusb
Bus 001 Device 002: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@rpizw-test:/root# lsusb
Bus 001 Device 008: ID 051d:0002 American Power Conversion Uninterruptible Power Supply
Bus 001 Device 007: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@rpizw-test:/root# lsusb
Bus 001 Device 010: ID 051d:0002 American Power Conversion Uninterruptible Power Supply
Bus 001 Device 009: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@rpizw-test:/root# lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@rpizw-test:/root# lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@rpizw-test:/root# lsusb
Bus 001 Device 016: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@rpizw-test:/root# lsusb
Bus 001 Device 019: ID 051d:0002 American Power Conversion Uninterruptible Power Supply
Bus 001 Device 018: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@rpizw-test:/root# lsusb
Bus 001 Device 019: ID 051d:0002 American Power Conversion Uninterruptible Power Supply
Bus 001 Device 018: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@rpizw-test:/root# lsusb
Bus 001 Device 021: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@rpizw-test:/root# lsusb
Bus 001 Device 021: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@rpizw-test:/root# lsusb
Bus 001 Device 022: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@rpizw-test:/root# lsusb
Bus 001 Device 023: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@rpizw-test:/root#

@marc usually the kernel might reset a USB device due to instability of power supply (voltage drops too much at a moment). You may want to try a different (better) power supply. Also try not to put too heavy load on Zero4U's downstream ports.

Thanks for your kind and thoughtful response. You are absolutely correct about the voltage or current sagging. I do not think power is my issue. To test that theory, I've moved the RPi image to a Pi 3b+ with the same powersupply and same USB device. It's rock solid for over 16 hours. (see attached screenshot showing that the UPS USB device ID has not incremented in that 16 hours).

This leaves me scratching my head as to why I can't get the Zero4u board to be stable when attached to my Pi Z W's... Given that the 3B+ draws much more current than the Pi Z W, can we eliminate the power supply as a factor?

Could this be related to the Wifi radio? Perhaps I should try to disable the radio and see what happens? Just guessing at this point LOL