Discovery 3 with Raspberry Pi Zero 2W over current error

[rjratnip]

I have a Discovery 3 connected to a Raspberry Pi Zero 2W with a USB-C to micro USB adapter. The Discovery is recognized, but when I open an instrument I get a "The device has stopped working due to overcurrent" error. Checking the "Disable current limit" box has no effect. I have connected an external 5V supply to the discovery and still get the same error. Other things of note:

1. Connecting the Discovery to a computer with a USB-C to type A adapter causes it not to work at all. I did not see anything about that as being a problem. 

2. If I connect the Discovery to external 5V while it is connected to the Pi via USB, it draws no current through the 5V supply. Disconnecting the USB and reconnecting it causes the Discovery to draw about 600 mA through the 5V supply. Is this intentional?

Any help on the overcurrent error and how to fix it is appreciated.

Thanks.

[attila]

Hi @rjratnip

1. It could be an adapter/cable contact problem.
2. The AUX supply can only be blocked by the the under/overvoltage 4.11V/5.76V protection circuit.
You could have a grounding issue. Are the RPi and 5V supplies floating or grounded ? If both are grounded make sure to use nearby sockets, same splitter.
With the default 'USB Power' 'Stop with AUX' the USB supply line is turned off if the AUX voltage is ok, 4.5V...5.5V
If this option is 'Always ON' the USB and AUX currents will balance according the voltage/cabling resistance. If the USB voltage is higher than AUX, the AUX current will be lower. 

Verify the voltage of your supply or use powered HUB.

[rjratnip]

Thanks. I've tried multiple USB-C to type A cables and none work. I'm assuming it just doesn't work with a Type A, on a Windows PC or the Pi Zero 2W, even though some on this forum seem to have success with it. I also tried a powered USB-C hub and get the same problems. However, I'm also getting new errors after it kind of starts working, such as:

1. The device has turned off

2. Over temperature, >85C (this just after a couple of seconds of running)

3. Lost connection to the device.

4. And also still get the over-current error. And again, the check box to ignore the over-current appears to do nothing. The error keeps happening and pops up with that box unchecked even though I continue to check it and click 'OK'.

Since the Discovery seems to work fine on my Windows laptop, I'm assuming there are fundamental problems with it working on the Pi Zero 2W. Do I need a different Pi model? Unless there is some breakthrough info, I don't see it working on the Pi Zero. We kind of need the Pi Zero for form factor reasons, but if the Discovery 3 does not work on it then that's a mute point.

I'd appreciate hearing any other suggestions. The Pi Zero is running the recommended OS from the Raspberry Pi people, it has 512 MB of RAM, and I'm just trying to use the Digilent Waveforms App to see if things work before I delve into try to use the SDK in Python.

One last thing, the menu you show above with the "Stop with AUX" selection, that menu is all greyed out and, thus, i can't select anything. What does that mean?

Thanks.

Edited April 7 by rjratnip

[attila]

Hi @rjratnip

It could be a similar hub or driver problem as it is with RPi1,2,3 where FTDI USB packets are randomly lost or corrupt.

 

 

[rjratnip]

Thanks for your help so far. We upgraded to a Pi 4 and it works now.

I downloaded the Waveforms SDK and tried some of the test python scripts. Some work, others result in a segmentation fault. One that works is the test_temperature.py, which appears to measure the board temperature of the the Discovery. For some of the others, I stepped through the python code and when the device is opened, the device name is blank. I also see an enumeration in device.py that does not include the "Analog Discovery 3", which is what I have. What is the device name that is supposed to be reported with this device? Have the test scripts been updated for the 3 model or do I need another version of the SDK? 

From device.py:

device_names = [("Analog Discovery", constants.devidDiscovery), ("Analog Discovery 2", constants.devidDiscovery2), ("Analog Discovery Studio", constants.devidDiscovery2), ("Digital Discovery", constants.devidDDiscovery), ("Analog Discovery Pro 3X50", constants.devidADP3X50), ("Analog Discovery Pro 5250", constants.devidADP5250)]

Thanks for any help.

[attila]

Hi @rjratnip

See the following post: